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OF CONTROLLING 2elaleuca IN SOUTH
A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE
UNIVERSITY OF FLORIDA
I would like to start off by thanking my husband Jeffrey Finn who has traveled this
journey with me and been the best partner I could have ever hoped for. I especially thank
him for the encouragement and perspective that he has offered me along the way.
I wish to express eternal thanks to my Mom, Gena Carte, for her never ending
support and for always telling me that I can do whatever I set my mind to, even when it
feels like it is impossible.
I wish to express my deepest gratitude to my Dad, Jerry Carter, for showing me the
value of hard work, fostering my appreciation for nature, and for teaching me to hunt and
fish better than most men.
My deepest gratitude goes out to my committee members Dr. Alan Hodges, Dr.
Donna Lee, and Dr. Mike Olexa for their guidance along the way. I am especially
grateful to Dr. Hodges who worked with me on a day to day basis and taught me so
much. His patience and dedication are appreciated more than he will ever know.
I wish to offer special thanks to the USDA-ARS for funding this research. I would
like to express my gratitude to Francois Laroche of the South Florida Water Management
District and the members of the TAME Melaleuca team, especially Cressida Silvers, Paul
Pratt, and Amy Ferriter for always being willing to answer "just one more question."
Many thanks go to Sharon Wallace of the South Florida Water Management District,
Debbie Gillet of the Southwest Florida Water Management District, Chris Wassil and
Gary Lewis with the Florida Division of Forestry, and Gail Baxley with the Florida
Department of Environmental Protection' s Office of Park Planning for sharing their data,
insight, and experiences with me. Thanks go to Carol Fountain for all of her formatting
I would like to express my thanks to all of the friends I have made in graduate
school. They are the reason I will look back on this whole experience and have pleasant
memories filled with smiles and laughter. Thanks go to the best study group around,
Erika Knight, Jamille Palacios, Anne Jones, and Jennie Varela; the first year core would
have been impossible without them. I am especially grateful for the fact that at the first
day of orientation I sat next to Erika Knight and struck up a conversation; her friendship
has been priceless. Special thanks go to Damian Adams for being a great colleague and
wonderful friend. Thanks go to comedians Justin Taylor (GO RACERS!i) and Athur
Mabiso for always offering an easy laugh and "Respect." Thanks go to Annie
Hildebrand for offering me big beautiful smiles when I needed them the most.
Special thanks go to my friend Beth-Anne Blue for all of her wisdom, guidance,
and s port and es ecially for reminding me that I could do this.
I would like to acknowledge the close family members who are no longer here with
me to share in the j oy of this accomplishment: my Grandparents Pepa and Grammie
(Red and Mary) Carter, Gov (Gran-Daddy Victor B. Carte, Jr.), and step-father Scott
Whidden. I wish to thank them for all of the love and support they offered during their
Last, but certainly not least, I offer my thanks to God, for with Him everything is
TABLE OF CONTENTS
ACKNOWLEDGMENT S .............. .................... iv
LI ST OF T ABLE S ................. ................. ix......... ...
LI ST OF FIGURE S .............. .................... xi
AB STRAC T ................ .............. xii
1 INTRODUCTION ................. ...............1.......... ......
Origins, Introduction, and Invasion ................. ...............2................
The War Against M~elaleuca ............ ..... ._ ...............3...
Problem Statement ............_....... .__ ...............5....
Public Lands vs. Private Lands................ ...............6.
Hypotheses & Parameters Estimated ................. ...............7................
Research Objectives............... ...............
2 LITERATURE REVIEW .............. ...............9.....
Introduction to Benefit-Cost Analysis ................. ...............9................
Formal Theoretical Framework Behind BCA ................. ............... ......... ...11
Benefit Cost Analysis and Social Welfare Theory .......... ................ ...............13
Individual Welfare Changes ................ ...............13........... ....
Social Welfare Changes .............. ...............16....
Benefit-Cost Analysis in Practice............... ...............17
Use of Mail Surveys ..................... ........... ...........1
The Contingent Valuation Method (CVM) .................. ...............21..
Previous Research on the Economic Impacts of Melaleuca .............. ...............25
3 SURVEY DESIGN, CONTENT, AND ADMINISTRATION .............. ...............27
Survey M ethod s .................. .... .......... .. .. ........ ............ 2
Survey Study Area, Target Populations, and Sampling .............. ....................2
Survey Content .............. ...............28....
Residential Survey ................... ...............29.......... ......
Professional Land Manager Survey ................. ...............31................
Survey Administration............... .............3
4 SURVEY RESULT S .............. ...............34....
Results for Professional Managers .............. ...............34....
Land Ownership Status............... ...............34.
Land U se................ .. ... .. ............3
Factors Affecting Land Management ................. ............. ............... 36. ....
Area Occupied By Invasive Plants and Area Treated .............. ....................3
Methods Used for Treating M~elaleuca .............__..... ........._........41
Barriers to Controlling M~elaleuca ......................... .............__ ............4
Sources and Usefulness of Information for M~elaleuca Control.............._.._.......47
Costs for M~elaleuca Control .......__ ......... __ .........___.....__......50
Impacts of2 ~elaleuca ................. ...... .... .... ... ..... .........5
Annual Income or Budget and Comparison of Reported Melaleuca Control
Expenses .............. ...............54....
Results for Residents .............. ...............56....
Invasive Plant Awareness............... ...............5
Amount of Melaleuca on Property ............_......__ ....__ ...........5
Use of Control Methods for M~elaleuca ......____ ........ .........._.......5
Barriers to Controlling M~elaleuca .....__.....___ ..........._ ............5
Information Sources for M~elaleuca Control ......____ ...... .. ...............59
Expenses for M~elaleuca Control ........._..._......__ ....__ ............6
Impacts on Property Values............... ......... .... ..........6
Willingness to Pay for M~elaleuca Removal/Eradication .............. ........._.....61
Impacts of Melaleuca on Outdoor Enj oyment ........._._..... .... ....___ ..............62
Willingness to Pay to Reduce M~elaleuca in Outdoor Activity Areas ........._......63
Respondent Demographics ................. ....___ ....___ .............6
5 BENEFIT COST ANALYSIS ........._... .....___ ...............67...
Calculation of Benefits .............. ...............68....
Ecosystem Benefits ................. .... ..... .............7
Agricultural Land Productivity Benefits .............. ...............73....
Agricultural Land Market Value Benefits .....__.___ ..... ... ._ ........._.... ..74
Recreation Benefits .............. ...............74....
Additional Benefits ................. ...............76........... ....
Calculation of Costs .................. ............. ...............77......
Calculation of the Benefit-Cost Ratio ................. ...............80........... ...
6 SUMMARY AND CONCLUSIONS ................ ...............83................
Sum m ary ................. .. ... .. ....... ... ........ ...... .........83
Conclusions, Implications, and Policy Recommendations ................. ................ ...85
Recommendations for Future Work .............. ...............88....
A MELALEUCA MANAGEMENT SURVEY OF PROFESSIONAL LAND
M ANAGERS ................. ...............90.......... ......
B MELALEUCA MANAGEMENT SURVEY OF RESIDENTIAL PROPERTIES ...99
LIST OF REFERENCE S ................. ...............113................
BIOGRAPHICAL SKETCH ................. ...............117......... ......
LIST OF TABLES
4-1 Land area managed by surveyed professional land managers in Florida. ................35
4-2 Land use types and areas managed by professional land managers in Florida. .......36
4-3 Factors influencing management decisions by professional land managers in
Florida. ............. ...............38.....
4-4 Land area infested with and treated for invasive species by professional
managers in Florida ................. ...............41........... ....
4-5 Methods used for treatment of2~elaleuca by professional land managers in
Florida. ............. ...............43.....
4-6 Number of professional managers using various control methods and area of
M~elaleuca treated in Florida, 2003 and 1990-2003 .......____ ...... ..__ ............44
4-7 Intentions for future use of various M~elaleuca control methods by professional
managers in Florida. .............. ...............45....
4-8 Requests for more information on M~elaleuca control methods by professional
managers in Florida. .............. ...............45....
4-9 Barriers to controlling Melaleuca by professional managers. .............. ..............47
4-10 Information sources and types of media used by professional land managers in
Florida. ............. ...............48.....
4-11 Usefulness of information received by professional land managers in South
Florida. ............. ...............50.....
4-12 Costs for M~elaleuca control reported by professional land managers in Florida,
2003 ....._..__ ........__ ....__ ....__ ....__ ....__ ..............51
4-13 Expenses for special equipment for M~elaleuca control by professional managers
in Florida. ............. ...............5 1....
4-14 M~elaleuca treatment cost trends reported by professional land managers in
Florida. ............. ...............52.....
4-15 Negative impacts of2~elaleuca reported by professional land managers in
Florida. ............. ...............53.....
4-16 Reduction in utility due to M~elaleuca infestation reported by professional land
managers. ........... ..... ._ ...............54...
4-17 Annual income or budget for land management by south Florida professional
managers, 2003 ........... .......__ ...............55...
4-18 Awareness of 2elaleuca and invasive plants by Florida residents. .......................56
4-19 Amount of Melaleuca on property of Florida residents .................... ...............5
4-20 Methods used for M~elaleuca control by Florida residents, and interest in more
information about control methods. ............. ...............57.....
4-21 Barriers to controlling Melaleuca by Florida residents............_.._ ..........___.....58
4-22 Sources of information on M~elaleuca received by Florida residents. ....................59
4-23 Expenses for Melaleuca control by Florida residents, 2003. ............. ...............60
4-24 Negative effect of M~elaleuca on property value of Florida residents.....................6 1
4-25 Willingness to pay for removal of2~elaleuca from property by Florida residents..62
4-26 Days of annual outdoor recreation activity reported by south Florida residents,
2003 ........._.._. ....._... ........_. ....._. ...._... ....._. .........._.63
4-27 Effect of2~elaleuca on outdoor enj oyment by Florida residents. ........._................63
4-28 Willingness to pay per visit to reduce M~elaleuca in recreational areas by Florida
re sidents ........... ....... __ ...............64..
4-29 Demographics characteristics of surveyed south Florida residents, 2003. ...............66
5-1 Ecosystem Values for Surveyed Land Use Classifications............... .............7
5-2 Average Negative Impact Values for Surveyed Land Use Classifications. .............73
5-3 Total Benefits of2~elaleuca Control in 2003 ........._._ ....... ................77
LIST OF FIGURES
4-1 Average weighting of factors influencing management by professional land
managers ................. ...............39......_ ._ .....
4-2 Usefulness rating of information sources and media by professional land
managers in Florida ........._ ............ ...............49....
Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science
SOCIO-ECONOMIC IMPACTS OF CONTROLLING2~elaleuca INT SOUTH
Chair: Donna Lee
Major Department: Food and Resource Economics
M~elaleuca quinquenervia, commonly referred to as M~elaleuca, was introduced to
Florida in the late 1800s and has flourished in the state since its introduction. In the late
1980s and early 1990s efforts to eradicate/control M~elaleuca began in earnest. The
Areawide Management Evaluation of2~elaleuca (TAME) program was created
specifically to research and address the problems and unique situations associated with
M~elaleuca control. Public agencies in Florida spent an estimated $25 million on control
efforts from 1989 to 1999 and have succeeded in reducing the area it covers; however,
private landholders have been less aggressive in its removal. Despite the control efforts
on public lands, the lack of treatment on private lands has allowed M~elaleuca to spread in
many areas and resulted in no net loss of the acreage covered.
M~elaleuca causes a reduction in ecological function, agricultural productivity, and
recreational use value of lands occupied. In order to document the current management
and socio-economic impacts of this species, surveys were mailed to 2,000 agricultural
landowners, 285 park/preserve managers, and 5,000 randomly selected residents in the
ten southernmost counties of Florida in 2004.
Survey results revealed that M~elaleuca covered more than 620,000 acres of land
and that professional managers (both park/preserve and agricultural) had treated
approximately 86,731 acres during 2003. A benefit-cost analysis was conducted for the
areas controlled in 2003. The benefits were estimated based on the values for restored
ecological function of agricultural and park/preserve land, agricultural productivity and
market value of agricultural land, the recreational use of park/preserve lands where
M~elaleuca controls had been implemented, and avoidance of costs connected with
M~elaleuca fueled fire control. Total benefits amounted to $23.3 million. The costs were
derived from the residential and professional survey data along with TAME M~elaleuca
program costs which include the costs associated with this research. Total costs
amounted to $13.2 million
The resulting benefit-cost ratio (1.76) indicates that the benefits of2~elaleuca
removal were significantly greater than the costs, and that control efforts provided a net
social benefit to society in the year 2003. Therefore, it is recommended that the policy
stay in effect until the benefits no longer outweigh the costs.
An invasive species as defined by the 1999 Executive Order 13112 is "an alien
species whose introduction does or is likely to cause economic or environmental harm or
harm to human health." Invasive species have affected many, if not most, countries
around the world in some way. In some cases, alien species are purposefully introduced
for bona fide reasons; case in point, the now infamous Kudzu used for ornamental
purposes, erosion control, and livestock forage. In other situations a species is
inadvertently introduced through increased global travel, such as the Brown Tree Snake's
introduction to Guam. Some alien species are introduced and remain rather innocuous
throughout their lifespan. However, often times they can cause devastating and
irreversible consequences, such as the almost total annihilation of Guam' s songbird
population and Kudzu's prolific spread throughout the Southeast and Hawai'i to now
cover several million acres of land.
Every year, a growing number of individuals make Florida their new home.
However, this phenomenon is not limited to humans. Plants, animals, and pathogens also
find ways to make this accommodating sub-tropical land their home as well. Florida' s
mild winters and warm wet summers are quite hospitable to many different species and
allow non-native residents to become resident aliens. One especially destructive alien
invader that has now become an invasive species is the highly problematic tree
commonly known as M~elaleuca (M~elaleuca quinquenervia).
Origins, Introduction, and Invasion
M~elaleuca also had a rather innocent beginning in Florida. It is thought to have
been introduced in Florida by Royal Palm Nurseries in Manatee County around 1887.
The tree was popularized by nurseries and gained greater recognition due to its ability to
thrive in many environments and rapidly provide shade and windbreaks for home owners
(Serbesoff-King 2003). It was subsequently planted in swampy areas to help dry up the
standing water so developers could build to meet the demand of the booming South
Florida population (Laroche and McKim 2004). This notion has now become the subject
of much debate amongst scholars. While some scientists adhere to the belief that
M~elaleuca consumes more water than native vegetation, others argue that their research
indicates that it does not use any more water than the average plant.
In 1941, Florida populations of2~elaleuca from Lake Okeechobee southward
began to increase as the US Army Corps of Engineers (USACE) planted the trees along
levees and spoil islands for erosion control (Stocker and Sanders 1981). This fast
growing species has now become established, and has spread much more quickly in
Florida than in Australia, and competes with many native plant species (Rayamajhi et al.
2002). Due to its rapid growth and reproduction rates, Melaleuca may completely
dominate landscapes that it invades, thus decreasing biodiversity and precluding the
growth of native vegetation (Schmitz and Hofstetter 1999). Studies show that patches of
M~elaleuca can spread to dominate one square mile of land in only 25 years (Laroche and
Ferriter 1992). M~elaleuca may also increase wildfire danger, because the dense stands
burn with greater intensity making fire control more difficult (Diamond et al. 1991).
The War Against Melaleuca
While this tree has been on Florida soil for more than 100 years, its control was not
seriously pursued in the state until the latel980's. This is due, in part, to the movement
to restore the Everglades. During the 1990's, the framework leading up to the
Comprehensive Everglades Restoration Plan (CERP) began to be developed. After the
foundation was laid by the previous Water Resources Development Acts of 1992 and
1996, President Clinton signed the Water Resources Development Act of 2000, Section
601 which authorized the CERP. When it became clear that invasive species would only
serve to thwart the goals of CERP which are restoring, preserving, and protecting South
Florida's ecosystem, measures were taken to address the growing problem. Specifically,
the M~elaleuca Eradication and Other Exotic Plants proj ect, within the CERP, was
designed to address exotic and invasive species management and control in Southern
Florida (CERP 2004). Recognizing the need to take aggressive action against invasive
species, in 1993 the Florida legislature enacted statutes that require agencies such as the
Florida Department of Environmental Protection Bureau of Invasive Plant Management
(FDEP-BIPM) to investigate methods of control for M~elaleuca and to implement those
control methods within their jurisdiction (FS 369.252). Under current state law it is
illegal to sell, transport, collect, cultivate or possess any plant, including any part or seed
of the species M~elaleuca quinquenervia without a permit from the FDEP or the Florida
Department of Agriculture and Consumer Services (FDACS) (FS 369.251).
In 1997 the legislature directed the Bureau of Invasive Plant Management (BIPM)
to build a program to bring exotic upland species under maintenance control, by enacting
Florida statute 369.22. The statute details that a maintenance control program is "a
method for the control of non-indigenous aquatic plants in which control techniques are
utilized in a coordinated manner on a continuous basis in order to maintain the plant
population at the lowest feasible level as determined by the department" (FS 369.22 p.1).
The 1993 Florida legislature also set aside an annual budget of $1 million to the FDEP
specifically for Melaleuca control. The FDEP took the award from the legislature and
then entered into a cost-sharing program (called the M~elaleuca Program) with the South
Florida Water Management District (SFWMD) in which they match that award dollar for
dollar (BIPM 2003.) The goal of the M~elaleuca program is to control M~elaeluca on all
SFWMD land and to maintain the lowest possible infestation rates while minimizing
impacts to non-target plant species. In order to prevent the wider spread of the plant,
outlying lesser infested areas are treated first according to a quarantine strategy (BIPM
2003). The goal of the FDEP is to reduce infestations of upland invasive exotic plants on
public lands by 25 percent by the year 2010 based on the estimated 1995 level of
infestation of 1.5 million acres (BIPM 2003). It should be noted that this estimated area
is for all upland invasive species and not just M~elaleuca.
Additionally, The Areawide Management Evaluation of Melaleuca (TAME
M~elaleuca or TAME) has been established under the auspices of the USDA Agricultural
Research Service (ARS) Areawide Pest Management initiative to demonstrate the
efficacy of an integrated approach that can be applied to invaded areas for control of
M~elaleuca. This group has proceeded to implement the control recommendations of the
M~elaleuca Task Force as enumerated in the Florida Exotic Pest Plant Council's
(FLEPPC's) M~elaleuca Management Plan (Pratt and Ferriter 2001). TAME has
subsequently teamed up with the Food and Resource Economics Department (FRED) at
the University of Florida' s Institute of Food and Agricultural Sciences (UF-IFAS) to
conduct this research into the socio-economic impacts of2~elaleuca in South Florida.
Estimates place the coverage of~elaleuca at anywhere from 200,000 to 500,000 acres of
land in South Florida. From 1989-1999 Florida agencies have spent about $25 million on
its control and have succeeded in reducing the area it covers on public land by about
100,000 acres (Pratt and Ferriter 2001).
A maj or problem with the spread of2~elaleuca is that it causes a reduction of
economically viable uplands and ecologically sensitive wetland areas. A general estimate
of the value of environmental and economic services provided by wetlands is $14,785 per
hectare per year (Costanza et al. 1997). Assuming minimal losses of one percent, and a
current infestation of 200,000 hectares, the diminished value would be almost $30 million
per year. Farmers and ranchers are losing valuable grazing and crop land while natural
areas such as parks/preserves are losing natural habitats, which in turn affect plant and
animal diversity. M~elaleuca invades utility easements such as power lines, canals, and
other waterways, thus impairing their use, and often makes costly tree removal necessary
to maintain the use of these service areas. It has been proj ected that the unfettered spread
of this plant would severely limit the use of parks and recreational areas by tourists and
residents causing a negative impact to the Florida economy at $160 million annually
(Diamond et al. 1991). Additional reports show that by the year 2010 an estimated $1.76
billion in damages would be caused due to the various negative impacts it has on
recreation, ecotourism, fires, and loss of endangered species (Balciunas and Center
The maj ority of the information gathered through mail surveys focus on elements
traditionally used in determining the extent to which M~elaleuca covered land, how much
was being treated, what methods were being used to treat it, and the costs incurred for
those treatments. However, at the time this research was being carried out it was not
readily apparent that much was known about the negative effects caused by M~elaleuca
infestation. To help bridge the apparent information gap, additional data need to be
collected to determine how individuals perceived the effects that M~elaleuca infestations
have on ecological function, agricultural productivity, land market values, the use of land
for recreation and enj oyment of the outdoors.
Public Lands vs. Private Lands
For many years, the slogan of "Florida State Parks: The Real Florida" was used to
help promote tourism within the State' s park system. The general goal of having these
parks is to allow visitors to see Florida's natural state where it has been left relatively
untouched by human hands. However, invasive species, which often completely
dominate native flora and fauna, thwart the goal of preserving the "real Florida." In order
to meet this goal, non-native species must be removed. This need has been realized by
managers of the public lands and therefore control has been concentrated on these lands.
However, while its removal is a mandate for public agencies, one of the maj or
obstacles facing the success of2~elaleuca control is the fact that private individuals often
implement few or no controls. While it is technically illegal for private individuals to
possess M~elaleuca, very little is actually being done to force them to remove it from their
private property (with the exception of a few pro-active municipalities). This presents the
conundrum of falling infestation rates on public lands, while infestations flourish on
private lands and often cause cross-contamination in areas that have been treated (such as
public lands) or areas that have not yet been infested. The efficiency of treatment is
greatly reduced if public land managers continue to treat and kill M~elaleuca, while
private individuals allow for outlying infestations to spread. A comprehensive strategy
for inducing private citizens to control M~elaleuca is necessary if there is to be any chance
of gaining the upper hand in the war against its spread.
Hypotheses & Parameters Estimated
The issues surrounding the impacts that invasive species have on society are very
broad and far reaching. Previous research on invasive species has mainly focused on the
biological characteristics of the plants. Current research has started to focus on what
kinds of monetary and non-monetary impacts these invaders are having on the economy
and society as a whole. This research seeks to focus more on the socio-economic impact
that M~elaleuca has had on Florida in the region south of Lake Okeechobee. The
hypothesis that will be tested is that this analysis will yield a Benefit Cost Ratio (BCR)
for treating M~elaleuca that is greater than unity (1).
Parameters that will be estimated by this research are:
* What are the impacts/costs of reducing Melaleuca infestations in South Florida?
* What factors influence the choice of control method (or lack thereof)?
* How much money is currently spent on M~elaleuca controls?
* How much money would homeowners be willing to spend to remove Melaleuca
from their property?
* How much money would residents be willing to spend to reduce M~elaleuca in the
places where they engage in outdoor recreational activities?
* What is the BCR for controlling M~elaleuca?
The general obj ective of this research is to determine the economic impact that
M~elaleuca has had on professional land managers and residents in South Florida, along
with evaluating the socio-economic impact of its control. This will require gathering
information including (but not limited to) which control strategies are currently being
used, how much they cost, and what area is currently being treated. It is hoped that this
research will shed some new light on why individuals are more or less likely to
implement control measures. Then policy makers and implementers can custom tailor
outreach and education programs to increase the area of Melaleuca being treated.
A specific obj ective of this research is to measure the benefits and costs associated
with the treatment of2~elaleuca infestations for the year 2003. Trying to eradicate a
species that has such a stronghold on a large area of ecologically sensitive and
economically valuable land is not cheap. A large amount of money has been and will
continue to be spent if this program is to be considered successful. It is imperative to
determine whether the benefits of controlling this invasive species outweigh the costs.
As a matter of public policy, the resources being allocated to this program should provide
a net benefit to society. A benefit-cost analysis will provide information to determine if
the resources being allocated to this fight are economically justified.
The legislative aim of controlling M~elaleuca has many far reaching implications for
society. Current research is beginning to focus more on the socio-economic impact of
invasive plants. A combination of tools is necessary to fully evaluate the socio-economic
affects of controlling M~elaleuca. Among the tools available, this study employs the use
ofBenefit-Cost Analysis (BCA) and Contingent Valuation (CV) through mail survey
admini strati on.
Introduction to Benefit-Cost Analysis
Every day new proj ects and policies are proposed in both the public and private
sectors. Decision makers are then faced with the daunting task of deciding which of the
myriad proj ects or policies will help to achieve their desired goal or end result. Over
time, BCA has been used extensively to help determine the economic viability of
legislation and investment projects. Since the 1930s BCA has been used by many U.S.
agencies to determine if the benefits of their policies outweigh the costs to society (Prest
and Turvey 1965). Many past U.S. Presidential administrations have recognized the
value that this type of analysis can provide by attempting to clearly delineate the costs
and benefits of a proposed policy/course of action (Whittington and Grubb 1984).
Through Executive Order 12291 signed on February 17, 1981, President Ronald Reagan
sought to standardize and make permanent the requirement for federal agencies to
conduct BCA on all "major" regulations.
Due to the fact that some policies and regulations can result in "win-lose"
situations, analysis needs to identify the winners and the losers and exactly how those
groups will be affected. Sassone and Schaffer (1978) point out that the need for careful
analysis is especially important in large scale public proj ects with irreversible
consequences. A thorough analysis can help to identify normally "unforeseen" costs that
tend to creep up during the life of a proj ect. Policy makers or proj ect managers can then
develop strategies and contingency plans that will help to mitigate these circumstances.
There are many definitions on what constitutes a BCA. However, there are
generally some key similarities between the definitions of the process. One description
suggests that BCA is a "generic term embracing a wide range of evaluative procedures
which lead to a statement assessing costs and benefits relative to proj ect alternatives"
(Sassone and Schaffer 1978, p.3). Another more specific definition states that it is "a
process of identifying, measuring, and comparing the social benefits and costs of an
investment project or program" (Campbell and Brown 2003, p. 1). BCA has been
described as a procedure for "measuring the gains and losses to individuals, using money
as the measuring rod of those gains and losses and aggregating the money valuations of
the gains and losses of the individuals and expressing them as net social gains or losses"
(Pearce 1983, p. 3).
An integral part of a BCA is the identification of all relevant costs and benefits.
Another important step is the quantification of those costs and benefits (Sassone and
Schaffer 1978). It is important to note that these costs and benefits are analyzed by a
"with" and "without" comparison. Specifically, the analysis of the project seeks to assign
a value to the costs and benefits that occur "with" the proj ect and compare them to the
state of the world as it would exist "without" the project (Gittinger 1982). This is
different from considering the state of the world "before" the proj ect and "after" its
implementation. If a "before/after" comparison is used it neglects the change that would
take place without the proj ect and allows for an erred account of the benefits that can be
ascribed to the proj ect/policy. Campbell and Brown (2003) also point out that the
important concept of opportunity cost becomes a factor in the "with and without"
comparison. Without the project, scarce resources such as land, labor, and capital could
be designated to other uses. With the project, the opportunities. to use those same scarce
resources for some other beneficial purpose are foregone. Each possible outcome offers a
particular value to society. After completing a thorough analysis of the two possible
outcomes (with or without the proj ect) and determining the costs and benefits of the
proj ects the analyst can determine if the benefits exceed the costs. If this is the case, then
the proj ect would be recommended to the policy maker.
Formal Theoretical Framework Behind BCA
Using BCA to assign a monetary value to the effects a proj ect will have relies upon
two key assumptions. The first is that the social value of a proj ect is a summation of the
values of the proj ect to individual members of society. The second is that the value of a
proj ect to an individual is equal to their (fully informed) willingness-to-pay (WTP) for
the project (Sassone and Schaffer 1978). Willingness-to-pay is the specific expression of
the value an individual assigns to a commodity or service. This leads to an essential
conclusion in microeconomics that for any given price of a good, rational individuals
aiming to increase their state of well-being as much as possible, will purchase a number
of units of that good so that at the margin, their willingness to pay for that good just
equals its price. Therefore, if an effect of a proj ect were a small increase or decrease in
the number of units of a good accessible to an individual for consumption, that increase
or decrease has a social value equal to the number of units concerned multiplied by the
market price (Sassone and Schaffer 1978).
The formal BCA theoretical framework, reliant upon welfare economics, set forth
by Sassone and Schaffer (1978) indicates that a state (of the world) S is a particular
distribution of utility among the individual members of society; specifically demonstrated
(2-1) S =(U U2, ..., Uj,..., UN),
for a society made up of N members.
A well defined project, through intentional actions, will advance society from the current
state of status quo, So to an alternative state of S'. Vj is the value of a proj ect to an
individual j, and is their maximum WTP amount to have the proj ect implemented (when
they are in favor of the proj ect), and when they do not favor the proj ect, it is the negative
of the minimum amount of their willingness-to-accept as payment in order to remain just
as well off in S' as in So. If the proj ect does not alter individual j's utility then their
compensating variation, Vj = 0. Therefore, the social value of a project is the summation
of the individuals' willingness to pay, identified by C Vj.
Actually acquiring each individual's willingness to pay can be problematic in two
ways (Sassone and Schaffer 1978). First, each individual would have to have perfect
knowledge of every aspect of the project. The impracticality of this is readily apparent
due to the fact that many of the people actually involved with the proj ect are often not
fully aware of every detail. The second difficulty lies within the fact that individuals are
often unable or have difficulty in defining their own compensating variation by stating an
arbitrary number. The aforementioned reasons lead to the suggestion that some other
form of acquiring the individuals compensating variations is necessary. Sassone and
Schaffer (1978) suggest that this information is best gleaned by using interviews or
Benefit Cost Analysis and Social Welfare Theory
As suggested in the previous section, welfare economics provides a theoretical
basis for BCA. Although BCA did not originally evolve from welfare economics it has
come to rely upon the foundation that welfare economics creates (Cohn 2003). It has
been suggested that BCA is an application of welfare economics (Sassone and Schaffer
1978). While Sassone and Schaffer (1978) provide a very general introductory
framework for BCA (as shown in the previous section), Cohn (2003) provides a more in-
depth analysis into its theoretical basis.
Individual Welfare Changes
Following the assumption that each individual xl, x2, ..., Xn has n goods and
services (including savings) available to him or her, a utility function of Ui for the ith
individual is expressed as:
(2-2) Ui = U(xil, xi2, ..., Xin).
If a new government policy is introduced that has an impact on some of the quantities of
goods and services that individual i consumes, the change in utility ensuing from a
change in the quantity of the jh gOOd or service is defined as:
(2-3) AUi = E(MUij)Axij.
M~Uij describes individual i's marginal utility for an added unit of j, and Axig is the change
in the quantity of good or service j that the individual receives. From the microeconomic
principle stated earlier, it is known that an individual will select goods and services so
that the marginal utility for any good, j, would be equal to the price of the good, pj,
multiplied by the individual's marginal utility of income (M~UYi), given as the following:
(2-4) M~Uij = (M~UYi)pj.
By substituting equation (2-4) into equation (2-3), the following results:
(2-5) AUi = C(M~UYi)pj~xij.
The change in the income of individual i due to the change in the quantities of goods and
services brought about by the new government policy is found in the term pjxij. Finally,
the change in individual i's utility is equal to the change in income weighted by the value
of the individual's marginal utility of income.
Due to the fact that a new government policy will affect many people it is
important to know what change in social welfare is due to the new policy. This can be
found by determining the changes in the individual utilities of m persons affected by the
policy using the social welfare function:
(2-6) W= W(U1, U2, U3, ..., Um),
where Wrepresents social welfare. Taking equation (2-6) into consideration, a change in
social welfare is noted as:
(2-7) AW= M'= (AU1, AU2, AU3, ..., AUm),
where AW represents the change in social welfare.
Keeping in mind that Arrow's Theorem questions the possibility of deriving a
social welfare function at all, Cohn (2003) suggests that the real issue is whether an
"acceptable" function can be developed. One maj or stumbling block for this is the
interpersonal comparison of utility, which some economists argue condemn BCA. While
there are cases when various forms of social welfare functions do not provide an
acceptable social choice, the argument can be made that a flawed social welfare function
is better than none at all. Therefore, equation (2-7) can be differentiated to the form of:
(2-8) dW= C(8W/8Ui)dUi,
(2-9) W = C(M~S~i) Ui,
where M~SUi demonstrates the change in social welfare arising out of the change in the
utility of the ith individual. M~SUi is also known as the distributionall weight" given to
individual i' s utility. In other words, it reflects the societal value of the changes in the
individual' s level of utility.
Substituting equation (2-3) into equation (2-9), the following is obtained:
(2-10) A W= CE(M~UYi,) (M~SUi)pyAxij.
This equation illustrates the changes that occur in social welfare due to a new public
policy that influences the quantities of goods and services available to individuals in
society. It is the sum of the fluctuations in effective income for every individual
weighted by the product of the marginal utility of income of the individual i, (M~UYi,), and
the changes in the quantities of goods and services as a result of the new policy, pj~xij.
Assuming that all individuals have identical marginal utilities of income and changes in
utility associated with the new policy, then the marginal utility of income (M~UYi) and
marginal social utility (M~SUi) will each equal one and the change in social welfare (due
to the new policy) is equivalent to the change in national income due to the policy.
According to Cohn (2003) and Zerbe and Dively (1994), the marginal social
utility and marginal utility of income are difficult to estimate which causes many analysts
to restrict their analyses to the efficiency aspect of the equation. This causes the equation
that reflects the change in welfare to be reduced to:
(2-11) AW= CE pjAxij.
However, it must be kept in mind that if the marginal utilities of income and marginal
social utilities vary significantly among those influenced by the policy, and the end goal
is to maximize social welfare; the BCA could result in erred decisions. If the analyst
feels that ignoring the marginal utilities of income and marginal social utilities is
detrimental then he/she should avoid BCA that does so.
Social Welfare Changes
It should be noted that Arrow' s Impossibility Theorem (originally developed from
research on election procedures) casts some doubt as to whether a social welfare (choice)
function can be derived from an aggregation of individual preferences to allow for the
optimal allocation of resources (Arrow 1963). This is due to the fact that the following
conditions must be met before a "fair" social welfare function can be derived:
* Unrestricted domain or universality. The social welfare function must include each
* Non-imposition or citizen sovereignty. All societal preferences should be
achievable through some set of individual preferences.
* There must be at least as many individuals as there are options being debated.
* Non-dictatorship. The social welfare function should not be sensitive to only one
individual. The function is responsive to more than one individual's requirements.
* Monotonicity or positive association of social and individual values. The social
welfare function should promote the change or not change at all if an individual
modifies their preference order. An individual should never be penalized for
modifying their preference.
* Independence of irrelevant alternatives. If the social choice function focuses on a
specific subset of alternatives, then the resulting outcome will be compatible with
those specific alternatives. If individuals change their ranking of "irrelevant"
alternatives it will have no impact on the social ranking of the "relevant"
alternatives. This implies a limitation on the sensitivity of the social function.
Benefit-Cost Analysis in Practice
Benefit Cost Analysis has been used for analyzing a broad spectrum of proj ects.
Stober and Falk (1967) offer a discussion on using BCA for proposed local water
allocation programs to help determine how a community should allot water among the
various needs within a community. Faced with two alternative scenarios, the authors
offer analysis on a reimbursable community proj ect that can supply water at a lower cost
than that at which industrial and municipal users can meet their own needs. By
formulating a benefit-cost ratio (BCR), they can determine if the community project is
justified. They finally determine that the structure of corporate income taxes and the
community's lower costs of capital provide a large bias in favor of the community
supplied water proj ect.
Benefit Cost Analysis has been used to evaluate the economic feasibility of
treatment/eradication programs for other invasive species in Florida. In 2004, Zansler
conducted a BCA of the Citrus Canker Eradication Program (CCEP). This study
investigated the effects that citrus canker would have on the citrus industry if it were
allowed to become endemic, to demonstrate the benefits of the CCEP. Estimates of the
costs were determined by the change in the cost of production and government
expenditures on eradication of citrus groves in Florida.
This form of analysis has been used to estimate the gains and losses from policies
aimed at providing increased product safety for consumers. Dardis, Aaronson, and Lin
(1978) used BCA to evaluate flammability standards of children' s sleepwear as well as
investigating the role BCA plays in determining whether product safety regulations are in
the public interest. The research first delineated the general costs and benefits associated
with implementing this safety regulation. Then, actual monetary values were assigned to
the related benefits and costs of the safety regulation. Upon completing their BCA, the
researchers determined that the new safety standard was cost effective in spite of a
decrease in consumer choice.
Haveman (1976) provides a summary of two cases using benefit cost analysis on
human resource programs. The first case looked at the benefits and costs associated with
the Upward Bound program. This government program was designed to recognize "high
potential, disadvantaged youths" at the high school level, who would probably not be
attending college, and provide them with specialized college preparatory education to
help lessen the education gap for less privileged students. The research evaluated the
benefits and costs of the program from the perspective of the pupils enrolled in it, as well
as the benefits and costs of the program as viewed from the rest of society. The study
determined that the students viewed this program as a worthwhile activity; therefore, they
believed the benefits outweighed the costs (using five and 10 percent discount rates).
The additional analysis indicated that the program's benefits outweighed its costs for the
society at large, as long as the discount rate used is below seven percent.
The second case study addresses the benefits and costs associated with a federal
government program "designed to provide institutional training in occupational skills to
adult workers." The cost-benefit analysis sought to determine if the program was a
valuable social investment. The study showed that increases in the participant' s income
could be attributed to the program. Additionally, social benefits and costs of the
programs were compared to reveal that the length of the program affected the ratio of
benefits to costs. The shorter courses had higher benefit-cost ratios than the longer
courses, where the present value of the costs exceeded the present value of the benefits.
Gittinger (1982) offered analysis on various agricultural proj ects, and specifically
carried out a BCA on the Philippine Ilocos Irrigation Systems Improvement Project by
formulating a BCR for the proj ect.
Blum, Damsgaard, and Sullivan (1980) provided a general discussion of the use of
BCA in health care as it relates to three following areas:
* The use of BCA for analysis of disease-specific programs of intervention from a
prospective point of view (for illnesses such as polio, syphilis, and renal disease).
This has historically concentrated on the economic impact of such diseases
measured by the untimely loss of life or capacity to function due to the illnesses.
* BCA has been used as a technique for the evaluation of alternative means of
delivering medical services. Hospitals have used BCA to assist in determining if it
would be cost effective to construct new ambulatory care centers or if the funds
should be used for improving existing emergent care facilities.
* BCA has been implemented to estimate the return on public investments in areas
such as medical research and health manpower development.
Use of Mail Surveys
Surveys have proven to be a useful tool in many areas of study for gaining insight
into people's opinions and beliefs, or obtaining general quantitative information. More
surveys are conducted by mail than through any other means (Dillman 1991). The U.S.
Office of Management and Budget' s 1984 research reported that 90 percent of the
government' s surveys categorized as "self-administered"' were conducted through mail
procedures. The use of mail administered surveys has distinct advantages and
disadvantages (Dillman 1991, Benson 1946, and Kramer and Schaffer 1954).
One of the greatest advantages that has helped mail surveys gain popularity is the
relatively low cost of implementing mail surveys when compared with interviews
conducted in person or by telephone. The relative simplicity of administering mail
surveys allows organizations and individuals to conduct the surveys themselves as
opposed to hiring outside agencies. Mail surveys also make it possible to contact
individuals when they are scattered across a broad geographic region. Additionally, by
accessing the necessary lists of potential respondents, mail surveys can be efficient at
reaching specific subsets of the population such as college graduates, homeowners, or
agricultural land owners. When mail surveys are used, the interviewer bias observed in
phone surveys or personal interviews is eliminated. When anonymity is assured by the
entity conducting the survey, the respondent is likely to be more forthcoming in mail
questionnaires as opposed to personal interviews. Finally, when the necessity arises to
gather responses from all household members, mail surveys allow those members to be
reached relatively easily as opposed to scheduling additional interviews if all the
necessary members are not available at one particular time.
One of the disadvantages of using mail surveys is that it is impossible to tell
whether the respondent answered on their own or solicited answers from outside sources.
If it is imperative that the respondent give only their personal opinion or answer questions
based on their current level of knowledge, then mail surveys cannot assure this. The goal
of gaining a representative sample of the population can be problematic, because those of
higher education and/or income levels may be more likely to reply than those of a lower
socio-economic class. Another difficulty is that the responses gathered by mail surveys
can be biased towards those who are inclined to one or extreme or the other. In other
words those with more polarized biases are more likely to respond than those who are
uninformed or have more moderate positions on the subj ect.
Due to the threat of respondent fatigue, mail surveys must be kept relatively brief
to avoid non-responses attributed to a lengthy questionnaire document. Furthermore, the
importance of question sequence is lost on mail surveys due to the fact that nothing really
prevents the respondent from perusing the whole questionnaire before actually answering
the questions. Finally, only a limited amount of demographic information can be gleaned
from mail surveys. Respondents often feel that this line of questioning is too invasive,
especially when copious amounts of personal information are requested.
It is imperative for a researcher to consider the pros and cons of the various
methods used to gather survey information. No one survey method can be endorsed as
better than another; the decision must be made on a case by case basis. According to
Kramer and Schaffer (1954) when considering the disadvantages of a technique the
researcher must ask if:
* They are factors that would significantly influence the results of the survey?
* Does the disadvantage limit the scope of the technique or does it eliminate the
technique for their particular area of inquiry?
* Does the disadvantage apply to all survey techniques or just the particular one
* Are there any techniques to mitigate the disadvantageous effects?
The Contingent Valuation Method (CVM)
It is especially difficult to measure or put a monetary value on irreplaceable goods
like health or the environment. Often the market fails to establish prices for public goods
because they are nonexclusive. This is why there is the need to find out what values
people place on these public goods. Hanemann (1994) points out that a survey or
questionnaire offers a way to demonstrate public demand for a good, especially when
indirect methods fail to offer a complete measure of a person's value for a particular
good. While price systems are one way to determine how people establish what
something is worth; another way is to simply ask them through surveys or votes
Mitchell and Carson (1989) submit that in general, the Contingent Valuation
Method (CVM) appears as accurate as other methods, and is capable of measuring types
of benefits that other methods can measure only with difficulty, if at all. The fact that
economists now have a tool to value goods, previously thought almost impossible to
value, has helped this valuation method gain worldwide popularity (Navrud 1992). The
CVM uses survey questions to determine an individual's preferences for public goods by
establishing what they would be willing to pay for specific improvements in them; thus
eliciting their willingness-to-pay (WTP) or willingness-to-accept (WTA) some loss in
dollar amounts (Mitchell and Carson 1989). If the study has been carefully designed and
pre-tested, the responses gathered should symbolize valid WTP responses (Mitchell and
Carson 1989). If the random sample gathered has a sufficiently high response rate and
appropriate measures are taken to adjust for non-respondents and poor quality responses,
the results can be generalized (with a known margin of error) to represent the population
from which the sample was taken (Mitchell and Carson 1989). The Carson et al. (1994)
bibliography lists more than 1600 studies and papers from more than 40 countries that
used CV on varied topics such as transportation, sanitation, health, the arts and education,
and the environment.
While there is no one standard for the design of contingent valuation surveys, it is
important for them to include several key elements, because the quality of responses is
directly related to the quality of the design of the survey. To begin, the survey must
contain a clear description of the policy/program that the respondent is valuing (Portney
1994). If a clear description is lacking, the respondent will likely be less able to
accurately value the situation in question. The survey must include a means for eliciting
a value or a choice from the respondent, through the use of tools such as referendum
formats, open-ended questions, or bidding games (Portney 1994). Finally, CV surveys
usually seek to gather the demographic information of the respondents along with their
attitudes toward the environment or a description of their recreational behavior for
environmental and/or natural resource studies (Portney 1994).
While the CVM is widely used around the world, the subj ect is not without debate
or its detractors. In 1992 a panel of experts, including Nobel laureates, was convened to
advise the National Oceanic and Atmospheric Agency (NOAA) if the "CVM was capable
of providing estimates of lost nonuse or existence values that were reliable enough to be
used in natural resource damage assessment" (Portney 1994, p.8). While the "bottom
line" of the panel report found that "CV studies can produce estimates reliable enough to
be the starting point of a judicial process of damage assessment, including lost existence
values," they also developed a strict and lengthy framework under which CV studies
should be conducted if they were to produce reliable estimates (Portney 1994, p. 8).
Among those guidelines, the panel stated that face-to-face interviews are preferred to
telephone surveys and telephone surveys are preferred to mail questionnaires, and that
studies should gather information on willingness to pay to prevent future incidents
instead of determining minimum compensation required for an event that has already
occurred. Additionally, studies using CV should implement the referendum format,
where respondents are asked how they would vote for a particular program that would
achieve some level of environmental benefit in exchange for higher taxes or commodity
prices. The panel offered that the reasoning behind this guideline is that these types of
decisions more accurately reflect the reality of real world decisions and would provide a
more accurate valuation than the typical open-ended question that seeks a maximum
willingness-to-pay value. The panel also stated that analyses using the CVM should open
with a scenario to accurately illustrate the anticipated effect of the program being
considered as well as a reminder that a willingness-to-pay amount for the proposed
policy/program would reduce their disposable income. Finally, follow-up questions
should be provided to ensure that the individual could comprehend the choice they were
being asked to make and to discover the reasoning behind their response.
Some economists critical of the CVM have charged that it is not useful because, in
their view, the resulting information is contrary to economic theory (Hanemann 1994).
To that end, critics have suggested that the CVM is insensitive to scope, thereby making
it an unreliable method for obtaining useful information regarding natural resource
damage estimates. Kahneman and Knetsch (1992) put forth that their study of WTP for
the clean-up of lakes in Ontario, Canada shows that respondents' WTP to clean up all of
the lakes in Ontario is less than the WTP for the clean up of lakes in a specific region.
Logic would suggest that an individual's WTP for cleaning up a larger number of lakes
would be higher than their WTP for cleaning up a smaller area of lakes. It has been
argued that this insensitivity to scope is unavoidable because "respondents are expressing
ideological values, receiving a warm glow, or purchasing moral satisfaction"
(Kahnemann and Knetsch 1992, p. 64). The NOAA panel also included a requirement
that studies using the CVM should test for the sensitivity of responses to the scope of the
damage described in the scenario. To address this issue the panel suggested that the
questionnaires should seek to determine whether or not the respondents were willing to
pay more to prevent more serious ecological accidents.
Previous Research on the Economic Impacts of Melaleuca
While the biological research on M~elaleuca is now quite extensive, there is a
noticeable paucity in the amount of economic research that has been conducted on this
invasive species. However, there are a few researchers who sought to analyze the
economic impacts that M~elaleuca has had in Florida relatively early in the eradication
program's life. Balciunas and Center (1991) discussed the prospects and dilemmas that
could arise if biological control is used in the fight against Melaleuca. Additionally, they
conducted a Benefit Cost Analysis under the assumption that M~elaleuca is allowed to
spread unchecked. Their research helped to provide a good starting point for the benefits
and costs to be enumerated. For the purpose of this research, however, the Balciunas and
Center research is used as a guide to show the worst case scenario for the negative
Diamond, Davis, and Schmitz (1991) also provided additional research on the
economics of the M~elaleuca invasion. They specifically considered the economic impact
associated with the addition of2~elaleuca to the Florida Prohibited Aquatic Plant List and
provided a more extensive Benefit Cost Analysis of the spread of2~elaleuca. The
authors went into great detail considering possible effects of~elaleuca on Florida' s eco-
tourism, sport fishing and game hunting, as well as its effects on Florida agriculture and
the ecosystem in general. They also specifically provided useful cost figures for the
economic damages caused by wildfires fueled with M~elaleuca. Their research helps to
provide a checklist of sorts to ensure a thorough analysis. However, due to the fact that
both of the previously mentioned articles were written during the early stages of the
M~elaleuca eradication/treatment initiative, and the changes that have taken place since
then, they will have a rather limited application in this research.
SURVEY DESIGN, CONTENT, AND ADMINISTRATION
As discussed in the previous chapter, this research used mail surveys to gather part
of the information necessary to this proj ect. The quality of a survey's design is arguably
the deciding factor as to whether it will yield useful and reliable data. Over time,
research has been undertaken to try to devise a recipe, of sorts, that survey designers can
follow to help increase the likelihood that their surveys will yield their greatest potential.
This research uses Dillman's (1978) Total Design Method (TDM) as a guide for survey
Survey Study Area, Target Populations, and Sampling
The study area for these surveys included the 10 southernmost counties in Florida:
Broward, Charlotte, Collier, Glades, Hendry, Lee, Martin, Miami-Dade, Monroe, and
Palm Beach. Just over 2.5 million households are located in these counties (BEBR,
For the residential survey, a randomly selected sample of 5,001 households, which
represented 0.2 percent of the population, was purchased from a market research firm
(MSG, Inc.). Due to the fact that many Hispanic non-English speaking individuals reside
in South Florida, a Spanish language version of the survey mirrored each page of the
Both agricultural owners/operators and managers of public parks/preserves were
targeted for the survey of professional land managers. Agricultural land owners were
selected from a list compiled from county property appraisers by the Florida Department
of Revenue in Tallahassee. A random sample of 2,000 landowners with property
classified for agricultural use was selected for the survey. This sample represented 17
percent of the population of about 1 1,500 landowners.
For public lands, a list of 285 names was obtained from the United States
Department of Agriculture-Agricultural Research Service (USDA-ARS) representing
managers of parks and preserves for local, state, and federal government agencies, and
managers of rights-of-ways for public utilities. Surveys were mailed to all managers on
Beginning in fall 2003, two separate questionnaires were developed for the
respective survey groups of residents and professional land managers. The content of
these questionnaires was developed in consultation with The Areawide Management
Evaluation of Melaleuca (TAME M~elaleuca) proj ect collaborators at the University of
Florida Institute of Food and Agricultural Sciences (UF-IFAS), USDA-ARS, and the
South Florida Water Management District (SFWMD). The questionnaires and informed
consent protocol for the survey were reviewed and approved by the University of Florida
Institutional Review Board (UF-IRB) for compliance with ethical standards for human
subject research. Following the suggestions in Dillman's (1978) TDM, each survey had
an arrangement of various colored photographs on the front cover. Inside the front cover
included an introductory statement explaining who was conducting the study, the purpose
of the questionnaire, the importance of providing a response, general instructions for
completing and returning the questionnaire, the anticipated length of time for completion
of the survey, a guarantee of confidentiality, contact information should the participant
have any questions, and a statement of gratitude for participating in the study. The
residential survey was seven pages in length for each language, yielding 14 total pages,
inclusive of the opening instructions and areas provided for comments. The professional
land manager survey was a total of nine pages. Each survey concluded by thanking the
respondents for their participation and asking that they return the questionnaire in the
postage-paid envelope provided. Copies of the survey materials are provided in the
The residential survey was designed to help provide some insight into attitudes,
opinions, and experiences with M~elaleuca by the general public. The survey
questionnaire focused on determining the extent of residents' knowledge and experience
with both invasive plants and M~elaleuca specifically. The content of the survey can be
broken down into three categories: (1) an introductory assessment of experience with
and knowledge of2~elaleuca, (2) an assessment of opinions and willingness-to-pay
information, and (3) demographic information. An introductory line of questions were
posed to determine the respondent' s level of awareness of invasive plants in the state.
Residents were asked to indicate if they could recognize M~elaleuca and if they were
aware of its non-native status. Then, respondents were asked to indicate how much, if
any, M~elaleuca was located on their property. The next questions in the survey sought to
determine what control methods residents were currently using or interested in learning
more about, along with any factors that limited their ability to control the plant.
Residents were also asked to indicate from which sources they received information
about Melaleuca. The first section ends by asking the respondent to estimate what range
of money they had spent (since 1990 or owning their property) specifically for the control
of Melaleuca on their property. If the amount was over $500 the respondents were asked
to write in the estimate.
The second section began by asking respondents to indicate whether they felt that
M~elaleuca had negatively affected their property value. If the respondent answered
"yes", they were asked to then indicate by what percentage it had negatively affected the
value. Residents were also asked to indicate how much they would be willing to pay to
remove/eradicate M~elaleuca on their property. If they were willing to pay more than
$500 they were asked to write in a specific amount. Respondents were then given a list
of outdoor activities and asked to indicate how many days they engage in those activities
on an annual basis. The respondent was provided with space to write-in an activity that
was not listed. Residents were asked if Melaleuca had in any way affected their
enj oyment of the outdoors. If the respondent answered yes, they were then asked to
specify if they had been negatively or positively affected. The second section concluded
by asking respondents to indicate how much they would be willing to pay, per visit, to
reduce M~elaleuca in the areas where they engage in outdoor recreational activities. If the
amount was more than $25 per visit, they were asked to write-in a specific amount.
The third and final section of the residential survey sought to gather demographic
information about the respondent. Information was gathered on the zip code in which
they resided, the duration of residence at their current location, and the ownership status
of their residence. Questions such as gender, year of birth, educational achievement,
ownership of 25 or more acres of land in Florida, participation in state/local elections,
household size, and pre-tax income (for 2003) were also asked. Space was also provided
for the respondents to add any comments they had as well as to indicate their name and
address if they wished to receive a summary of the survey results.
Professional Land Manager Survey
While there are some similar questions in the two surveys, the survey administered
to the professional land managers was intended to gather more technical information on
the level of infestation and practices used for the control of~elaleuca. Both professional
agricultural land managers and park/preserve managers received the same survey
questionnaire. The content of the manager' s surveys can be broken down into two
categories: (1) general descriptive information reflecting the management unit, and (2)
specific information on M~elaleuca control. In the first segment, managers were asked to
indicate their name followed by their organization's name, address, and telephone
number. They were then asked to specify in which counties their land holdings or
management units were located. In order to determine the ownership classification of
their land, managers were asked to indicate how much of their land was privately owned,
publicly owned, or privately leased. To gather more specific information on the land's
use, managers were asked to indicate how many acres of their land fell within certain
categories, such as cropland, commercial timberland, park/preserve, etc. In the hopes of
gaining some insight into the factors affecting land management decisions, respondents
were asked to indicate whether various factors exerted significant, moderate, or no
influence over their management choices. The managers were then asked to report how
many acres of exotic plants currently occupied their management area as well as indicate
how many acres of each plant had been treated from 1990-2003.
The section of the survey specifically designated to acquire information on
M~elaleuca began by asking managers to indicate what control methods they had used on
M~elaleuca. They were then asked to specify the area treated for each control used during
2003 and from 1990-2003. Managers were also asked to indicate if they had not used
any control measures for Melaleuca. Respondents were asked to indicate whether they
planned to continue using or to adopt specific control measures for M~elaleuca, and
indicate if they would like to receive more information on any of the control types listed,
as well as indicate the types of sources that provided M~elaleuca control information to
them. Managers were asked to indicate any reasons that limited their ability to control
M~elaleuca on their property. Additionally, the managers were asked to rate the
usefulness of the information in terms of "useful", "somewhat useful", or "not useful".
Respondents were asked to indicate the costs for control of2~elaleuca on their
management unit during 2003 as well as indicate the total expenses for any special
equipment or heavy machinery purchased specifically for the control of~elaleuca since
1990. The survey went on to ask respondents to indicate if the total costs of Melaleuca
control on their land had increased, decreased, or stayed about the same over the past five
years. Managers were also allowed to indicate that they "didn't know" the trend. If the
respondent indicated that the costs had increased or decreased they were asked to indicate
by what percentage. Respondents were also asked to indicate if they felt that M~elaleuca
had reduced their land's agricultural productivity, lowered its market value, impaired its
ecological function, or diminished its recreational use. If the respondent indicated that it
had negatively affected one of these aspects they were asked to provide the percentage
loss that Melaleuca had caused. Professional managers were also asked to indicate their
organization' s gross income or annual budget for land management from 2003.
Participants were given the option of writing in a specific amount, indicating a range, or
indicating that they did not know the amount. Finally, managers were given the option of
adding additional comments as well as indicating whether they would like a copy of the
results through the mail or e-mail.
Survey administration was begun in June 2004 following the protocol of the TDM
(Dillman). An introductory letter was first mailed to all targeted respondents to notify
them that they had been selected for the survey, explaining the purpose of the survey, and
requesting their cooperation. Approximately one week later, questionnaires were mailed
along with a postage-paid return envelope and a cover letter restating the purpose of the
study. Reminder postcards were mailed one week later. A second complete mailing of
the survey and reminder postcard was repeated six weeks later.
After the completed surveys were received from respondents and categorized into
the appropriate group (i.e.-park/preserve managers, agricultural managers, and
homeowners) a code number was assigned to each completed questionnaire. The survey
responses were entered into an Excel worksheet and then verified for accuracy. If contact
information was provided in the response, follow up phone calls or emails were used for
verification or clarification as necessary.
Results for Professional Managers
Land Ownership Status
Land area owned and leased by professional managers responding to the survey is
summarized in Table 4-1. A total of 5.4 million acres were reported, which consisted of
about 5.1 million acres controlled by park managers and 317,000 acres controlled by
agricultural mangers. The vast maj ority of land managed by park/preserve managers was
publicly owned, although 86,372 acres were privately owned.
In contrast, most of the land managed by agricultural managers was privately
owned. Publicly owned landholdings managed as parks/preserves averaged 74,488 acres
per manager, and ranged in size from four acres to 1,400,000 acres. Privately owned
agricultural landholding averaged 775 acres per manager and ranged from less than 1
acre to 140,000 acres. A relatively small amount of land was being privately leased by
both park and agricultural managers. When these numbers are expanded to represent the
full population of agricultural managers in the 10 county study area of South Florida, an
estimated 1.74 million acres would fall under private ownership, 73,893 acres would be
privately leased, and 8,884 acres would be classified publicly owned.
In terms of land use, some 6.94 million acres were reported managed by
park/preserve managers, and 319,771 acres were reported managed by agricultural
managers, giving a total of 7.26 million acres (Table 4-2).
Table 4-1. Land area managed by surveyed professional land managers in
Sum Mean Minimum Maximum
(Acres) (Acres) (Acres) (Acres)
Privately Owned 10 86,372 8,637 7 70,000
Publicly Owned 67 4,990,670 74,488 4 1,400,000
Privately Leased 3 7,925 2642 105 7,500
Managers 431 316,528
Privately Owned 390 302, 132 775 0.3 140,000
Publicly Owned 3 1,545 515 5 1,380
Privately Leased 38 12,851 338 1 2,700
Overall Total 511 5,401,495 10,570 1 1,400,000
The largest type of land-use by area as reported by survey respondents was for
parks/preserves, comprising a total of 4.80 million acres, or 73,883 acres per manager.
The next largest land uses reported by park managers were right-of-ways totaling
871,483 acres, followed by lakeshore (508,272 acres), mitigation areas or constructed
wetlands (373,017 acres). Miscellaneous other uses totaling 356,262 acres included target
ranges, recreational areas, and office buildings. Some park/preserve managers indicated
that some of their land was used for pasture/range land, crop production, fruit/citrus
groves, and nurseries, but none indicated that their land was being used as forest for
commercial timber production.
The most commonly reported land use by agricultural land managers was
pasture/rangeland, with 38 percent of respondents reporting a total of 143,243 acres,
averaging 853 acres per respondent. Crop land was the next largest land use reported
totaling 116,388 acres, followed by fruit/citrus groves (34,275 acres), and right-of-ways
(4,547 acres). Miscellaneous other uses totaling 18,272 acres reported by agricultural
managers included residences, ponds, horse farms, and barns. When these numbers are
expanded to represent the population of agricultural managers in South Florida, it is
estimated that a total of 1.83 million acres were being managed, including 823,647 acres
for pasture/rangeland, 669,231 acres for crop land, 197,081 acres for fruit/citrus groves,
and 26,145 acres for right-of-ways, and 105,064 acres for miscellaneous other uses.
Table 4-2. Land use types and areas managed by p -ofessional land managers ir Florida.
Park Managers Agricultural Managers Managers
Land Use Type
Mean Sum Mean
# Sum (Ac) # Sum (Ac)
(Ac) (Ac) (Ac)
Park/Preserve 65 4,802,389 73,883 8 30 4 4,802,419
Right of Way 16 871,483 54,468 36 4,547 126 876,030
Lakeshore 6 508,272 84,712 7 19 3 508,291
Miti gati on/W etl and 14 373,017 26,644 9 25 1 28 373,268
Pasture/Range 4 25,210 6,303 168 143,243 853 168,453
Crop 2 900 450 50 116,388 2,328 117,288
Fruit/Citrus 3 1,908 636 98 34,275 350 36,183
Nursery 5 19 4 103 1,395 14 1,414
Forest 0 10 1,351 135 1,351
Other Use(s) 16 356,262 22,266 83 18,272 220 374,534
Total of all uses 6,939,460 319,771 7,259,231
Factors Affecting Land Management
Survey respondents were asked to rate various factors that influenced their land
management decisions as either "significant", "moderate", or "none" (Table 4-3). These
factors included agency funding, adverse weather conditions, availability of agricultural
land, encroachment of urban land uses, foreign or other state competition, cost of inputs
or supplies, prices for crops, fruit, or livestock, invasive plants, predators, insect pests,
and the ability to conduct prescribed burns. The average ratings for each of these factors
are summarized in Figure 4-1, where each respondent's rating was assigned a number
value: 0 for "none", 1 for "moderate", and 2 for "significant".
For park/preserve managers, agency funding was the most influential factor in land
management decisions; being rated as significant by 77% and moderate by 19%. Perhaps
this is not surprising since many of these respondents work for local, state, or federal
agencies. Invasive plants were rated as a significant factor by 73% of park managers,
while 25% rated them as a moderate influence. The ability to conduct prescribed burns
was rated as significant by 39% of park/preserve managers, and as moderate by 23%.
Input costs were considered significant by 36% and moderate by 53% of park/preserve
mangers. Urban encroachment was rated as a significant or moderate influence by 28%
and 40% of these respondents, respectively. Adverse weather was viewed as a moderate
influence (71%), although this may be considered more important after the 2004
hurricane season. Only 8% indicated that predators or insect pests were a significant
factor in their management, while 42% rated these pests as moderate, and 50% gave
considered it of no significance. Factors other than those listed in the survey (such as the
general public, staffing, and wildfires) were rated as significant by 38% of park/preserve
managers. Factors that were considered to have little or no affect on the park/preserve
management decisions were prices (99%), availability of agricultural land (93%), and
For agricultural managers, factors influencing land management were rated lower
overall. Prices for crops, fruit and livestock was the most important factor, with 29%
indicating it was significant and 33% as moderate. The costs for inputs or supplies were
rated as a significant factor by 24% of agricultural managers and as moderate by 41%.
Adverse weather conditions were a significant factor for 23%, urban encroachment was
rated as significant by 23%, and availability of agricultural land was significant for 20%.
The latter finding may be due to the fact that most agricultural managers already
own/lease their land, so they aren't worried about acquiring any additional land, or it may
indicate that agricultural managers generally do not intend to expand their operations.
Some 19% of agricultural managers rated predators and insect pests as a significant
factor, with 46% rating them as moderate. Invasive plants were rated as significant by
16% and as a moderate influence by 43%. Foreign or other state competition was
generally not viewed as important, which is somewhat surprising given the significance
of commodity prices.
Table 4-3. Factors influencing management decisions by professional land managers in
Park Managers Agricultural Managers
Factor None Moderate Significant None Moderate Significant
% % % % % %
Agency funding 4 19 77 91 7 2
Adverse weather 15 71 15 40 37 23
Availability of ag. land 93 7 0 51 30 20
Urban encroachment 33 40 27 50 27 23
Competition 86 13 1 73 15 12
Costs 12 53 36 35 41 24
Prices 99 1 0 39 33 29
Invasive plants 3 25 73 41 43 16
Predators/ Pests 50 42 8 36 46 19
Prescribed burns 38 23 39 66 26 8
Other factors 44 19 38 89 3 8
0.7 1 7
Other Factors affecting mgmt.
Ability to conduct prescribed burns
Availability of Ag. Land
0.9 H Park Managers
Agency Funding .
0 0.5 1 1.5 2
Figure 4-1. Average weighting of factors influencing management by professional land
Area Occupied By Invasive Plants and Area Treated
The importance of2~elaleuca as an invasive plant was assessed in relation to other
invasive plants, based on the area currently occupied in 2003, and the area treated during
the period 1990 to 2003. The area occupied was intended to represent the areas of
contiguous stands, not very small isolated patches and individual outlying trees. The ratio
of area treated since 1990 to the area occupied currently was also taken as a gauge of the
intensity of treatment by land managers.
For park/preserve managers, M~elaleuca was the invasive plant reported to occupy
the largest area (619,317 acres) in 2003. M~elaleuca also had the largest area treated
during 1990-2003 (402,088 acres), which represents 65% of the area currently occupied.
Brazilian Pepper was the second most common invasive plant, occupying 425,805 acres
in 2003, with 75,215 acres treated between 1990 and 2003. This represented 18% of the
area occupied in 2003. Among other species, Old World Climbing fern (Lygodium)
occupied 1 13,884 acres, and 49,213 acres were treated (43% of area occupied).
Australian Pine (Casuarina) occupied 111,782 acres, with 16,598 acres treated (15%),
Cogon grass (Imperata) occupied 20, 147 acres, with 6,527 acres treated (32%), Tropical
Soda Apple (Solan2um) occupied 15,418 acres, with 3,475 acres treated (23%), and
miscellaneous other plants occupied 11,433 acres, with 7,094 acres treated (62%). Some
of the other plants frequently listed were air potato (Dioscorea bulbifera), downy rose
myrtle (Rhodomytrus tomentosa), latherleaf (Colubrina a~siatica), carrot wood
(Cupaniopsis anacardioicles), and cattail (Typha).
For agricultural managers, 94 managers reported a total area of 2,134 acres
occupied by Melaleuca in 2003, and 57 managers reported treating a total of 1,460 acres
during 1990-2003. This represented 68 percent of area occupied. This suggests that
agricultural managers have treated M~elaleuca at similar rates as park managers have,
however other indicators in this survey and other research imply that park managers have
acted much more aggressively. Tropical Soda Apple (Solan2um) was reported by
agricultural managers to occur on 10,393 acres in 2003, and 7,855 acres (or 76% of this
area) were treated. Brazilian Pepper (Schinus) occupied 7,096 acres and 2,768 acres
(39%) were treated. Miscellaneous other invasive plants, including air potato, dog fennel,
and smut grass, occupied 2,561 acres, and 2,094 acres (82%) of those plants were treated.
When these numbers are expanded to represent the total population of agricultural
managers, Melaleuca is estimated to cover 12,271 acres in South Florida during 2003,
and 8,395 acres were treated between 1990 and 2003. The area infested by other invasive
plants on agricultural lands is estimated at 139,058 acres, including 59,760 acres for
Tropical Soda Apple, and 40,802 acres for Brazilian Pepper (Schinus).
Table 4-4. Land area infested with and treated for invasive species by professional managers
Park/Preserve Managers Agricultural Managers
Area Currently Area Treated Area Treated
SpeiesOccupied Since 1990 Crety Since 1990
# Acres # Acres # Acres # Acres
Paper bark or Punk
tree (M~elaleuca) 59 619,317 54 402,088 94 2,134 57 1,460
(Ca~suarina) 55 111,782 50 16,598 29 34 15 5
(Schinus) 68 425,805 65 75,215 146 7,096 104 2,768
(Insperata) 33 20, 147 31 6,527 14 320 9 73
Old World Climbing
fern (Lygodium) 45 113,884 40 49,213 23 178 16 24
(Panicunt) 33 25,060 31 11,008 40 1,468 31 888
Tropical Soda Apple
(Solanunt) 32 15,418 25 3,475 37 10,393 32 7,855
Other plants 37 11,433 36 7,094 33 2,561 18 2,094
Total 362 1,342,846 332 571,218 416 24,184 282 15,167
Methods Used for Treating Melaleuca
Managers were asked indicate if they had used a specific method for controlling
M~elaleuca and then to indicate the area they treated with that method in 2003 and also
cumulatively from 1990 to 2003. Respondents were given a choice of several options:
Mechanical removal (felling, mowing, tilling, grubbing, disking, etc.)
Foliar or soil applied herbicides
Basal frill followed by herbicide treatment (also known as "hack and squirt")
Girdling followed by herbicide treatment (a ring of bark is removed from the base
of the tree and then treated with an herbicide)
* Felling followed by herbicide treatment on the cut stump ("stump treatment")
* Biological control with beneficial insects (natural enemies of the tree are released
which may cause stress in established trees and death of younger saplings)
* Biological controls combined with one or more other methods.
Since respondents were given the opportunity of indicating more than one control
method, a count was taken to see how many managers chose at least one control choice,
and this number was used to compute the percentage of managers responding in the
affirmative for using a particular control method.
Among park/preserve managers, 82% indicated they had employed the stump
treatment, 59% used hack and squirt, 51% used mechanical control methods, 28%
employed biological control, 21% used biological control combined with one or more
other form(s) of control, and 7% reported using some other method of control such as
Many agricultural managers did not have M~elaleuca on their property, and if they
did, many chose not treat it. So, it was not surprising that 71% of agricultural managers
had not used any particular control measures for Melaleuca. Among agricultural
managers who did use controls, 33% indicated they had employed mechanical methods
for control, 10% used foliar or soil applied herbicides, 8% reported using stump
treatment, and 4% used hack and squirt (Table 4-5).
Table 4-5. Methods used for treatment of2~elaleuca by professional land managers in
Metho UsedPark Managers Agricultural Managers
Number Percent Number Percent
Mechanical 31 51 70 33
Foliar/Soil herbicides 22 36 20 10
Hack and Squirt 36 59 8 4
Felling and herbicide (stump treatment) 50 82 16 8
Biological Control 17 28 3 1
Biological control + other method 13 21 0 0
Other methods 3 74 2
No Controls 13 21 149 71
The area of2~elaleuca treated using various control methods in 2003 and
cumulatively during the period 1990-2003 is summarized in Table 4-6. The total area
treated in 2003 was 86,731 acres, and the total area treated since 1990 was 422,449 acres.
For park/preserve managers, the total area treated in 2003 was 84,740 acres, and the area
treated since 1990 was 419,741 acres. The stump treatment (felling + herbicide) was used
over the largest area (303,933 acres) since 1990, followed by hack and squirt (52,476
acres), foliar or soil applied herbicides (36,622 acres), mechanical methods (16,625
acres), and biological control (12,642 acres). Biological controls combined with one or
more other methods) were used on 80,575 acres, and together with the area treated
strictly by biological control represented 93,217 acres. For area treated in 2003, the most
important method used was stump treatment (46,958 acres), followed by foliar/soil
herbicides (15,987 acres), and hack and squirt (11,494 acres). In comparing the area
treated in 2003 with the average annual rates since 1990, it is apparent that the use of all
treatment methods has accelerated in 2003 for parks/preserves.
For agricultural managers, overall area of2~elaleuca treated by any particular
method since 1990 was significantly less than the park/preserve managers, at about 2,707
acres, including mechanical methods (1,957 acres), stump treatment (274 acres), and
foliar/soil-applied herbicides (3 55 acres). The smaller area treated for 1990-2003 than for
2003 in some cases was apparently due to reporting errors.
Table 4-6. Number of professional managers using various control methods and area of
M~elaleuca treated in Florida, 2003 and 1990-2003.
Park Managers Agricultural Managers Total Area
Area Treated Area Treated Area Treated Area Treated Treated
2003 1990-2003 2003 1990-2003 1990-2003
# Acres # Acres # Acres # Acres (Acres)
Mechanical 20 4,592 22 14,669 43 1,367 37 1,957 16,625
Herbicides 15 15,802 15 36,267 15 185 8 355 36,622
Hack and Squirt 23 11,454 28 52,437 7 40 5 39 52,476
Felling + Herbicide
(stump) 37 46,562 37 303,659 14 396 10 274 303,933
Biological Control 7 6,310 10 12,600 2 3 2 42 12,642
Biological + Other 4 4,242 6 80,575 0 0 0 0 80,575
Other Control 3 20 3 110 0 0 1 40 150
Total* 109 84,740 121 419,742 81 1,991 63 2,707 422,449
* Total area excludes biological plus other control methods, to avoid double counting.
Managers were also asked to indicate whether they planned to use or continue
using various control methods (Table 4-7). Among park/preserve managers who
answered this question, the largest share intended to use stump treatment (85%), followed
by hack and squirt (72%), mechanical control (50%), and biological control (45%), or
biological control combined with other methods (40%). For agricultural land managers,
the maj ority intended to use mechanical methods (79%), with much fewer intending to
use foliar/soil applied herbicides (29%), stump treatment (27%) or "hack and squirt"
(16%). Very few agricultural managers expressed interest in biological control.
Table 4-7. Intentions for future use of various M~elaleuca control
methods by professional managers in Florida.
MethodPark< Managers Agricultural Managers
Number Percent Number Percent
Mechanical 30 50 58 70
Foliar/Soil herbicides 23 38 24 29
Hack and Squirt 43 72 13 16
Felling + Herbicide 51 85 22 27
Biological Control 27 45 4 5
Biological + Other 24 40 3 4
Other Methods 3 5 6 7
Managers were also asked whether they were interested in receiving additional
information about any of the specific Melaleuca control methods (Table 4-8). Most
park/preserve managers were interested in learning more about biological control (74%),
but a maj ority was also interested in foliar/soil applied herbicides and stump treatment
(65%), hack and squirt (58%), and mechanical methods (52%). Among agricultural
managers who responded to this question, 40% to 50% wished to learn more about
biological control, stump treatment, soil/foliar herbicides and hack and squirt. The low
interest in learning more about mechanical control, at the same time this group expects to
continue using this method extensively, suggests that this method is well understood.
Table 4-8. Requests for more information on Melaleuca control methods by
professional managers in Florida.
Method Park Managers Agricultural Managers
Number Percent Number Percent
Mechanical 16 52 12 25
Foliar/Soil herbicides 20 65 22 45
Hack and Squirt 18 58 22 45
Felling + Herbicide 20 65 24 49
Biological Control 23 74 24 49
Biological + Other 16 52 17 35
Other Methods 5 16 3 6
Barriers to Controlling Melaleuca
Land managers were asked to choose from a list of factors that may have limited
their ability to control M~elaleuca (Table 4-9). Among park/preserve managers, the
biggest barriers identified were inaccessibility to infestations (22%), expense (18%),
excessive size of infestations (15%), lack of cost sharing programs (13%), and lack of
time (12%). However, a significant proportion of these respondents (32%) indicated they
encountered other types of barriers not specifically identified in the question. Some of
these other barriers included: infestations are too small, lack of needed equipment or
knowledge to use controls, fear of harming other beneficial plants, fear of or dislike for
using chemicals, and environmental regulations. Although they were listed in the
question, some respondents wrote-in that lack of money and lack of time were barriers to
implementing controls. Only 13% of park/preserve managers said that M~elaleuca was not
a problem for them.
Agricultural land mangers responded quite differently to the barriers to control
question. Seventy-four percent indicated that they did not have M~elaleuca on their
property and 3 1% reported that M~elaleuca was not a problem for them even it they did
have it. Some 9% of agricultural managers reported that their infestations were too small,
6% indicated that controls were too expensive, 5% indicated they lacked the necessary
equipment to carry out control measures, and 5% indicated a barrier other than those
listed in the survey. No particular barrier was mentioned more than any other; however,
some respondents stated that there were no economic incentives for removing M~elaleuca,
that licenses were needed for purchasing the necessary herbicides, and that some areas
required permits for removing the trees. It is interesting to note that one respondent
stated that Melaleuca trees provide shade in pastures, which suggests that there may be
some benefits of2~elaleuca for agricultural use.
Table 4-9. Barriers to controlling M~elaleuca by professional managers.
BaniersPark Managers Agricultural Managers
Number Percent* Number Percent*
No M~elaleuca on property 17 281 227 74
Not a problem 8 13 96 31
Don't care 0 01 13 4
Infestations too small 5 81 28 9
Infestations too large 9 15 8 3
Controls won't work 0 01 3 1
Don't know how to use controls 3 51 8 3
No time to use controls 7 121 3 1
Afraid of harm 3 51 5 2
Afraid oflDislike 3 5 13 4
Infestation inaccessible 13 221 6 2
Lack equipment 5 81 16 5
Environmental regulations 2 3 4 1
No cost sharing 8 13 12 4
Controls too expensive 11 181 19 6
Other reason 19 321 14 5
* Percent of respondents answering this question.
Sources and Usefulness of Information for Melaleuca Control
Professional land managers were asked if they had received information about
M~elaleuca from one or more of 13 possible sources (Table 4-10). These respondents
were also asked to classify the usefulness of these sources as either "useful", "somewhat
useful", or "not useful" (Table 4-11). These classifications were scored on a scale of 2, 1
or 0 respectively in order to compute a weighted average rating (Figure 4-2).
Park/preserve managers who responded to this question indicated that state and
federal agencies were their main source of information, with 83% indicating that they had
received information from these sources, followed by UF/IFAS extension (72%), land
managers' advice (67%), pamphlets or bulletins (60%), land managers' observations
(58%), and professional organizations (52%). Other information sources or media that
were received by less than 50 percent of respondents were weed professionals, area
demonstration plots, TAME M~elaleuca, video cassettes or CDs, internet websites,
computer software, and email. In terms of the usefulness of information from state and
federal agencies, 88% of park/preserve managers rated it as a useful source, 10% rated it
as somewhat useful, and 2% indicated it was not useful (Table 4-11), representing an
overall average score of 1.9 (Figure 4-2). Other information sources with high usefulness
ratings were UF/IFAS extension (1.9), manager observations (1.8), land manager advice
(1.8), weed professionals (1.8), professional organizations (1.7), internet websites (1.7),
pamphlets/bulletins (1.6), and the TAME proj ect (1.6).
Table 4-10. Information sources and types of media used by professional land
managers in Florida.
Sources Park Managers Agricultural Managers
Number Percent Number Percent
State and federal agencies 50 83 31 44
Professional organizations 31 52 16 23
Land manager observations 35 58 12 17
UJF/IFAS extension 43 72 33 47
Weed professionals 25 42 10 14
TAME M~elaleuca 22 37 5 7
Land manager advice 40 67 13 19
Pamphlets or bulletins 36 60 17 24
Video cassettes or CDs 9 15 4 6
Area demonstration plots 12 20 4 6
Computer software 3 5 4 6
Web site/Internet 21 35 14 20
E-mail/direct notification 15 25 4 6
Other information source 5 8 9 13
Among agricultural managers who responded to this question, 47% indicated they
had received information from UF/IFAS extension, followed by state and federal
agencies (44%), pamphlets/bulletins (24%) and professional organizations (23%) (Table
manager observations (1.1), state/federal agencies (1.1), weed professionals (1.1), land
manager advice (1.1), and internet websites (1.1) (Figure 4-2). None of the agricultural
managers indicated they considered area demonstration plots, computer software/decision
aids, or email/direct notifications as being useful sources.
Other media Specified
Software Decision aids
Land Manager's Advice
State & Federal Agencies
0 0.5 1 1 .5 2 2.5
Figure 4-2. Usefulness rating of information sources and media by professional land
managers in Florida
Table 4-11. Usefulness of information received by professional land managers in South
Park Managers Agricultural Managers
Source Somewhat Not Somewhat Not
Useful Useful Useful Useful
Percent of Respondents
State/federal agencies 88 10 241 26 33
Professional organizations 77 19 5 37 20 43
Land mgr. observations 79 19 247 19 34
UF/IFAS extension 88 10 261 16 23
Weed professionals 79 18 3 52 4 44
TAME Melaleuca 63 30 713 7 80
Land mgr. advice 81 15 447 20 33
Pamphlets or bulletins 62 33 426 41 33
Video cassettes or CDs 43 36 21 14 7 79
Area demonstration plots 53 29 18 0 21 79
Computer software 14 43 43 0 14 86
Web site/Internet 79 15 640 16 44
E-mail/direct notification 47 37 15 0 14 86
Other information source 75 25 021 21 57
Costs for Melaleuca Control
Managers were asked to indicate the costs incurred during 2003 for the control of
M~elaleuca within the categories of contract services, labor (including wages and
benefits), equipment (fuel, maintenance, and rental), herbicides, and indirect costs (such
as administration and overhead). The total annual cost for controlling M~elaleuca for
surveyed park/preserve managers was $10.87 (Mn.). This included $8.07 Mn. for
contract services, $837,000 for labor costs, $796,000 for herbicides, $308,000 for
equipment, $330,000 for indirect costs, and $528,000 for costs miscellaneous other costs
(Table 4-12). Surveyed agricultural managers reported spending $205,000 in 2003 to
control M~elaleuca, with $130,000 for contract services, $29,000 for labor, $22,000 for
herbicides, $18,000 on equipment, and $5950 on indirect costs. If these numbers are
expanded to represent all agricultural managers in South Florida, a total of $1.18 Mn is
estimated to have been spent by these managers on controlling M~elaleuca in 2003.
Table 4-12. Costs for M~elaleuca control reported by professional land managers in
Park Managers Agricultural Managers
# Sum ($) Mean ($) Max ($) # Sum ($) Mean ($) Max ($)
Contract services 34 8,066,544 237,251 4,060,00 8 129,900 16,238 100,000
Labor 29 837,470 28,878 400,00 17 28,975 1,704 20,000
Equipment 26 308,428 11,863 225,00 18 17,855 992 5,000
Herbicides 33 796,401 24,133 425,00 19 21,610 1,137 15,000
Indirect 19 329,770 17,356 110,00 5 5,950 1,190 5,000
Other 7 527,500 75,357 500,00 1 500 500 500
Total 10,8 66, 113 204,790
Managers were also asked to indicate expenses for any special equipment or heavy
machinery purchased since 1990 specifically to control M~elaleuca. It is important to note
that these expenses may be partly captured in the previous section under annual costs for
equipment expenditures. Among park/preserve managers surveyed, 28% reported
spending a total of $1.44 Mn for special equipment, with a maximum expenditure of
$1.20 Mn, as shown in Table 4-13. Some 7% of agricultural managers reported spending
$244,000 on special equipment, which would represent a total of $1.40 Mn when
expanded to represent the population in the region.
Table 4-13. Expenses for special equipment for Melaleuca control by
professional managers in Florida.
Category Number Mean ($) Sum ($) Maximum ($)
Park Managers 25 57,556 1,438,900 1,200,000
Agricultural Managers 33 7,390 243,879 130,000
Managers were asked about how costs for controlling M~elaleuca on their land had
changed over the past five years; whether they had increased, decreased or remained the
same. If there had been a change, they were asked to indicate the percentage change
(Table 4-14). Among park/preserve managers, 21% indicated that costs had increased,
26% indicated that costs decreased, and 32% indicated no change. Of those who
indicated that costs had increased, the average estimated change was 253 percent, while
for those who said costs had decreased, the estimated average decline was 117 percent.
For agricultural managers, 11% indicated the costs had increased, 9% indicated a
decrease and 41% indicated that costs had stayed about the same. For those indicating a
change in costs, the average increase was 81% and the average decrease was 87%.
These results suggest that costs for M~elaleuca control may be increasing more for
park/preserve managers than for agricultural land managers. A plausible explanation
could be the fact that most park/preserve managers are managing sensitive ecosystems
and are mandated to control invasive plants such as M~elaleuca in order to keep their
management area in a more naturally pristine state. Many agricultural managers do not
seem to think that M~elaleuca is much of a problem so they are probably less interested in
removing it, along with the fact that some mangers find that it sometimes provides
benefits for their operations.
Table 4-14. Melaleuca treatment cost trends reported by professional land
managers in Florida.
Park Managers Agricultural Managers
Number Percent Change Number Percent
Increased 13 21 2531 11 11 81
Decreased 16 26 1171 9 9 87
Unchanged 20 32 40 41
Don't know trend 13 21 37 38
Impacts of Melaleuca
Information was sought from managers regarding any negative impacts that
M~elaleuca had on their land and management over the past Hyve years. The first part of
the question provided the respondents with a list of options as well as giving them the
opportunity to specify any other adverse impacts. A second part of the question sought to
quantify the impact in terms of the percentage change in function. Among park/preserve
managers, 88 percent of those who indicated any impact reported that M~elaleuca had
impaired the ecological function of their management area, while 3 5 percent indicated a
reduction in the recreational use or value of their land (Table 4-15). A small number of
park/preserve managers reported other impacts such as increased fire danger, restriction
of necessary clearances, and smoke management issues with prescribed burns. Among
agricultural land managers who answered this question, 59% indicated that M~elaleuca
had reduced their land's agricultural productivity, while 39% said it impaired ecological
function of their land and diminished its recreational use, and 20% said that their land
market values were reduced (Table 4-15). Some of the other negative impacts listed
included allergies caused by pollen and various maintenance problems such as damage by
falling trees to fences.
Table 4-15. Negative impacts of2~elaleuca reported by professional
land managers in Florida.
Number Percent Number Percent
Productivity 0 024 59
Lowered Market Value 0 0 8 20
Impaired ecological function 35 88 16 39
Diminished recreational use 14 35 16 39
Other impacts 4 10 8 20
As a follow-up, managers were asked to estimate the percentage change in value
or utility due to M~elaleuca infestation. Park/preserve managers estimated that the loss of
ecological function and recreational use averaged 23 %, while agricultural managers
estimated that M~elaleuca had caused an average loss of 25 % in recreational use and 24%
in agricultural productivity (Table 4-16).
Table 4-16. Reduction in utility due to M~elaleuca infestation reported by professional
Park Managers Agricultural Managers
Impact Mean Min Max Mean Min Max
(%) (%) (%) (%) (%) (%)
Productivity 0 18 24 3 100
Lowered Market Value 0 6 11 5 20
Impaired Ecological Function 24 23 1 10 11 22 1 50
Diminished Recreational Use 8 23 1 10 12 25 5 100
Other Impact 1 30 30 30 3 43 5 100
Annual Income or Budget and Comparison of Reported Melaleuca Control
Professional managers were asked to indicate their gross income from agricultural
operations or their agency's budget for land management activities for the year 2003, or
to indicate the appropriate range of values (Table 4-17). A small percentage of
park/preserve managers (16%) reported their actual budgets, which totaled $9. 1 Mn, and
averaged $650,000. Among park preserve managers, 30% indicated their budget was less
than $50,000, 7% said it was within the range of $50,001-$99,999, 11% indicated it was
$100,000 to $249,999, 9% said it was $250,000 to $499,999 range, 5% said it was
$500,000 to $999,999, and 29% indicated their annual income/budget was $1,000,000 or
more. Among agricultural managers, 10% reported actual income totaling $7.83 Mn.
Some 55% indicated their budget was less than $50,000, 6% had $50,001 to $99,999,
12% had $100,000 to $249,999, 2% had $250,000 to $499,999, 3% had $500,000 to
$999,999, and 6% had $1,000,000 or more.
Reported expenses for the control of~elaleuca were compared to reported income
or budget in order to gauge the relative level of effort allocated to this effort. If managers
chose to write in their income, that exact figure was used in the comparison., however, if
their income/budget was reported for a range of values, then the midpoint for that range
was used, and for the highest and lowest ranges (less than $50,000, $1 million or more)
$25,000 and $1.5 million were used, respectively. Only managers who reported both
expenses and budget/income information could be used for this analysis. The analysis
revealed that on average 38 % of park managers' budget was expended on control
measures for Melaleuca, as a weighted average. For some managers, reported expenses
were as much as 3 to 8 times more than their budget. A few of the respondents indicated
that less than 1% of their income/budget was used on controlling M~elaleuca. These
outliers may be due to reporting errors or may simply be due to the fact that some
agencies/operations are involved in deficit spending, i.e. spending more than their budget
Table 4-17. Annual income or budget for land management by south
Florida professional managers, 2003.
Income/Budget Range Managers
Number Percent Number Percent
Less than $50,000 17 30 105 55
$50,001--$99,999 4 7 12 6
$100,000--$249,999 6 11 22 12
$250,000--$499,999 5 9 3 2
$500,000--$999,999 3 5 5 3
$1,000,000 or more 16 29 12 6
Don't know 5 9 32 17
Appoxmae mont Number Mean Sum Max
Park Managers 14 650,386 9, 105,400 4,385,000
Agricultural Managers 46 170,213 7,829,795 2,450,000
For agricultural managers, an average of 4% of their income was spent controlling
M~elaleuca. The majority of these managers fell into the 1 to 5% range, and some
reported their control expenses were less than one percent, however, some indicated that
60 to 100% of their income went to controlling M~elaleuca.
Results for Residents
Invasive Plant Awareness
Citizen awareness of non-native flora and in the state of Florida is an important
issue for the management of invasive plants. In the resident survey, a series of questions
were included to gauge the public's level of knowledge about invasive plants generally,
and M~elaleuca in particular. The vast maj ority of the respondents (91%) indicated they
were aware that some plants and trees are not native to the State. Nearly as many (89%)
indicated they were aware that non-native plants could harm local indigenous plants. A
strong maj ority (71%) responded that they could recognize M~elaleuca, and an equal
percentage indicated that they were aware it was not native to Florida (Table 4-18).
Table 4-18. Awareness of2~elaleuca and invasive plants by Florida residents.
No Yes No Yes
Aware some plants are not native to Florida 85 898 9 91
Aware non-natives can cause harm 109 875 11 89
Can recognize M~elaleuca 288 689 30 71
Aware M~elaleuca isn't native to Florida 280 700 29 72
Currently have M~elaleuca on property 921 37 96 4
Amount of Melaleuca on Property
When residents were asked if they had any M~elaleuca on their property, only 4%
indicated in the affirmative. Of those who had M~elaleuca, 3 1% indicated they had only
one tree, 16% had two to five trees, and 31% had six to 20 trees. Three percent of
residents with Melaleuca had one-quarter to one-half of an acre of land infested, 9% had
one to four acres, and 6% indicated they had five or more acres of2~elaleuca on their
property (Table 4-19).
Table 4-19. Amount of2~elaleuca on
property of Florida residents.
Trees or acres Number Percent
One tree 10 31
Two-five trees 5 16
Six-20 trees 10 31
0.25 acre 1 3
0.5 acre 1 3
1-4 acres 3 9
5 + acres 2 6
Use of Control Methods for Melaleuca
The respondents who stated that they had M~elaleuca on their property were asked
to indicate which, if any, of the listed control methods they were currently using. Some
84% of residents indicated they had not used any control measures (Table 4-20).
Mechanical controls were used by 12 percent, foliar/soil-applied herbicides or stump
treatment were used by 3% each, while 1% indicated they had used hack and squirt,
biological control, or biological combined with some other control.
Table 4-20. Methods used for Melaleuca control by Florida residents,
and interest in more information about control methods.
Interested in Learning
Number Percent Number Percent
Mechanical 23 12 13 50
Foliar/Soil herbicides 5 3 18 69
Hack and Squirt 1 1 16 62
Felling + Herbicide 5 3 18 69
Biological Control 2 1 21 81
Biological + Other 2 1 16 62
Other Methods 0 08 31
No controls used 157 8
The respondents who had M~elaleuca were also questioned regarding control
methods they would be interested to learn more about. There was a very high level of
interest in learning more about biological controls, with 81% of respondents expressing
such an interest (Table 4-20). A maj ority of respondents were also interested in learning
more about foliar/soil-applied herbicides (69%), stump treatment (69%), hack and squirt
(62%), and biological control combined with other methods (62%). Interest was lower for
mechanical controls (50%). Some 31% indicated they were interested in some other
method of control, however, none specified what the other methods might be.
Barriers to Controlling Melaleuca
Residents were given a list of factors that potentially limit their ability to control
M~elaleuca and asked to indicate which of those factors applied in their case. Of those
respondents who indicated any barrier, 56% said that M~elaleuca was not a problem, 20%
did not care, 19% were afraid of or disliked using chemicals, 15% did not know how to
use controls, 13% lacked the necessary equipment, and 10 percent gave other reasons
(Table 4-21, Figure 4-3).
Table 4-21. Barriers to controlling M~elaleuca by Florida residents.
Barrier Number Percent
Not a problem 80 56
Don't care 29 20
Infestations too small 9 6
Infestations too large 12 8
Controls won't work 5 3
Don't know how to use controls 21 15
No time to use controls 9 6
Afraid of harm to other plants 6 4
Afraid of or dislike using chemicals 28 19
Infestation inaccessible 9 6
Lack equipment 18 13
Environmental regulations 3 2
No cost sharing 3 2
Controls too expensive 5 3
Other reason 15 10
Information Sources for Melaleuca Control
Residents were given a list and asked to indicate which sources and types of media
they had received information from or on the control of2~elaleuca (Table 4-22). The
most common source of information was newspaper, reported by 59% of those
responding to this question, followed by local/national news (47%), and state and federal
agencies (42%). Other sources were public television (29%), pamphlets/bulletins (28%),
UJF/IFAS extension (27%), weed professionals (17%), and professional organizations
(12%). Some miscellaneous other sources mentioned by 17% of respondents included
word of mouth, park or garden club tours, public speakers, personal research, or
educational classes. Finally, only 1% of respondents indicated that they had received
information from the TA1VE 2elaleuca proj ect.
Table 4-22. Sources of information on M~elaleuca received by Florida
Source Number Percent
State and federal agencies 152 42
Professional organizations 44 12
Land manger observations 20 6
UF/IFAS extension 96 27
Weed professionals 61 17
T AVE M~elaleuca 4 1
Land manager advice 23 6
Pamphlets or bulletins 166 28
Video cassettes or CDs 0 0
Area demonstration plots 20 3
Computer software 1 0
Web site/Internet 27 5
E-mail/direct notification 20 3
Local/national news 283 47
Newspapers 353 59
Public television 176 29
Other sources) 103 17
Expenses for Melaleuca Control
Residents were asked to indicate how much they had spent on controlling
M~elaleuca since owning their present property, or during the period 1990-2003, by
choosing the appropriate range of values or by estimating the amount if their
expenditures exceeded $500. As shown in Table 4-23, 93% of residents indicated they
had spent $0-$49, and it is most likely, given previous data, that the maj ority of
respondents in this category probably paid zero. One percent of respondents indicated
that they had spent $50 to $99. Nearly 2% spent $100 to $249 and the same number
spent between $250 and $500. Slightly over 2% of respondents spent more than $500 on
Melaleuca control. For those reporting expenses over $500, the average amount was
$1,992, representing a total of $1 1,950. If these numbers are expanded to represent the
entire population of households in South Florida, an estimated $15.3 million was spent on
Table 4-23. Expenses for M~elaleuca control
by Florida residents, 2003.
Expense Range Number Percent
$0-$49 380 93
$50-$99 4 1
$100-$249 7 2
$250-$500 7 2
$500+ 9 2
Impacts on Property Values
Residents were asked to indicate whether and by how much M~elaleuca had
negatively affected their property value. As shown in Table 4-24, 5% reported that
M~elaleuca had negatively affected their property value, and that values were reduced by
an average of 18 percent. However, the maj ority (95%) said it had not affected their
Table 4-24. Negative effect of2~elaleuca on property
value of Florida residents.
Effect Number Percent
140 440 95
Yes 24 5
If Yes, amount
Mean (%) 18
Max (%) 50
Willingness to Pay for Melaleuca Removal/Eradication
Residents were also asked to indicate the dollar amount they would be willing to
pay to have M~elaleuca removed or eradicated from their property. If respondents
indicated they were willing to pay more than $500, then they were asked to estimate the
amount. As shown in Table 4-25, 74% of residents indicated they would be willing to
spend $0 to $49, however, since many residents previously indicated M~elaleuca was not
a problem for them, the maj ority of respondents for this category likely would choose $0.
Only 11% indicated they were willing to spend $50 to $99, 6% would pay $100 to $249,
7% would pay $250 to $500, and 2% would pay more than $500. Of those respondents in
the last category, the amount they would be willing to pay averaged $1,500. When these
numbers are expanded to represent the population of households in South Florida it is
estimated that residents would be willing to spend a total of $13.7 Mn to have M~elaleuca
removed from their property, which is similar to the estimated amount actually spent (see
Table 4-25. Willingness to pay for removal of2~elaleuca
from property by Florida residents.
Expense Range Number Percent
$0-$49 224 74
$50-$99 34 11
$100-$249 19 6
$250-$500 20 7
$500+ 5 2
If more than
Impacts of Melaleuca on Outdoor Enjoyment
Residents were asked about the number of days per year they spent in various
outdoor recreational activities, and how 2elaleuca has affected their enj oyment of the
outdoors. Residents reported a total of 8,790 days per year observing/photographing
wildlife, 8,132 days for boating or ATV activities, 6,263 days for freshwater fishing,
3,434 days for camping/hiking, 601 days for hunting, and 22,475 days for other activities
such as golf, jogging, cycling, walking, gardening, tennis, swimming, and saltwater
fishing (Table 4-26). When asked about how M~elaleuca had affected their enj oyment of
the outdoors, 77% indicated that it had not affected them and 23% said it had (Table 4-
27). Furthermore, 95% of those affected said it had negatively affected their enj oyment of
the outdoors, while only 5% indicated it had positively affected them.
Table 4-26. Days of annual outdoor recreation activity reported by
south Florida residents, 2003.
Activity Number Sum Mean Max
photography 261 8,790 34 365
Boating/ ATV 304 8,132 27 200
Camping/ Hiking 242 3,434 14 150
Freshwater fishing 6,263
Hunting 49 601 12 75
Other Activity 207 22,874 111 1,000
Table 4-27. Effect of2~elaleuca on outdoor
enj oyment by Florida residents.
Response Number Percent
No 598 77
Yes 179 23
If Yes--Negative Effect 179 95
If Yes--Positive Effect 9 5
Willingness to Pay to Reduce Melaleuca in Outdoor Activity Areas
Residents were asked how much they would be willing to pay (per visit) to reduce
M~elaleuca in areas where they engaged in outdoor activities. They were given several
ranges of amounts, and if they were willing to pay more than $25 per visit were asked to
estimate the amount. Some 44% of respondents indicated they were willing to pay
nothing, 8% would pay something less than $1 per visit, 27% would pay $1 to $4, 9%
would pay $5 to $9, 7% would pay $10 to $15, 4% would pay $16 to $25, and 1% would
be willing to pay more than $25 (Table 4-28). When these numbers are expanded to
represent the population of households in South Florida, these residents would be willing
to pay an estimated total of $1.35 million to reduce Melaleuca in the areas where they
engage in outdoor activities.
Table 4-28. Willingness to pay per visit to reduce M~elaleuca
in recreational areas by Florida residents.
Expense Range Number Percent
$0 275 44
$0-$1 48 8
$1-$4 171 27
$5-$9 58 9
$10-$15 42 7
$16-$25 23 4
$25 + 9 1
If more than $25 Sum $500
estimated amount Mean $100
Demographic information such as age, gender, property ownership, household size,
and income were collected as part of this survey, to help understand factors influencing
attitudes and behavior toward M~elaleuca and other invasive plants. This information is
summarized in Table 4-29. In regard to length of residency, 63% had lived in their
current location for more than five years, 33% had lived there for one to five years, and
4% had lived there less than one year. Regarding property ownership, 89% of
respondents indicated they owned their home, and 2% owned agricultural, forestry or
other natural land in Florida. Some 57% of residents were male and 43% were female.
The average year of birth was 1947, the oldest respondent' s year of birth was 1911 and
the youngest was 1985. Regarding education level, 14% had a high school diploma or its
equivalent, 11% had completed a technical/trade school, 26% had some college education
or an AA degree, 23% had a bachelor' s degree, and 23% had a graduate or professional
degree. Some 80% of respondents indicated they had voted in a state or local election in
the last three years. A household size of 2 people was reported by 91% of respondents.
Regarding household income before taxes, 5% made less than $10,000, 7% received
$10,000 to $19,999, 12% received $20,000 to $29,999, 8% received $30,000-$39,999,
16% received $40,000 to $49,999, 6% received $50,000 to $59,999, 15% received
$60,000 to $79,999, 12% received $80,000 to $99,999 range, and 20% indicated they
made $100,000 or more.
Table 4-29. Demographics characteristics of surveyed south Florida residents,
Year of birth
Ownership of 25 or
more acres in Florida
Voted in state or local
Election in Past 2
Number of people per
Less than 1 year
Less than high school diploma
High school diploma or
Some college or AA degree
Less than $10,000
BENEFIT COST ANALYSIS
The primary data used for this analysis were gathered by the previously discussed
mail questionnaires; however, some additional data were gathered from other sources.
After the survey data and the additional data gathered were verified, analysis was
conducted to ascertain the benefits and costs of treating M~elaleuca in South Florida
during the year 2003.
This task included delineating the monetary values associated with a loss in
ecological function due to M~elaleuca infestation. Due to time constraints, monetary
values specific to South Florida ecosystems could not be generated by this research.
However, Constanza et al. (1997) provides the average global values of ecosystem
services based upon a synthesis of previous work. The analysis provides estimated
annual values for ecosystem services per unit area by ecosystem type. This research will
utilize these values assess a monetary value to ecosystem function gains from the
treatment of Melaleuca.
Due to the fact that park/preserve managers indicated that M~elaleuca diminished
the recreational use of the land they managed, a monetary value was assessed to the
losses in recreational value that were avoided by the treatment of the infested areas. The
Florida Department of Environmental Protection (FDEP) Division of Recreation and
Parks provided an estimate of the direct economic impact of the state park system
(Baxley, pers. comm.). The National Park Service and Florida State park's economic
impact of visitor spending at parks are based on the Money Generation Model 2 (MGM2)
developed at Michigan State University (MGM2 2003). The analysis provides
information as to the number of days visited by both local and non-local visitors, the
amount of money spent per day, the j obs created, tax revenue generated, the output
(revenue) generated by the parks, and other economic impacts generated by visitor
Calculation of Benefits
This analysis focuses on valuing benefits to ecological function, agricultural
productivity, agricultural land market value, and recreational benefits from M~elaletca
treatments on public and privately held lands. It is assumed that benefits can only accrue
in areas where M~elaletica has actually been killed and accrue immediately after treatment
and that a year of benefits accrues regardless of what time of the timing of treatment. In
addition it is important to note that just because an infestation of 2elaletica is treated
once does not mean that the j ob is done. Due to the tenacity of the species, multiple
follow up treatments are usually necessary for permanent control to be achieved. Annual
benefits may be diminished if sufficient follow up treatments are not implemented. A
model was developed that relates the areas of2~elaletica treated on specific categories of
land to a specific ecosystem value to calculate the benefits accruing to that land. The
equations used to determine the benefits of2~elaletica control are as follows:
90 10 445 10
(5-1) EB = RI le ((Aj/Mj)E(CjDx)) + R ItF C((Ak Mk) (xkDx))
j= 1 x= 1 k= 1 x= 1
(5-2) APB = RP Ib F C((Ak/Mk) C(xk)),
k= 1 x= 3
(5-3) MVB = RV Im F C((Ak/Mk) C(xk)),
k= 1 x= 3
(5-4) RB = R Y Ir C((Aj/Mj) (Cxij))/L,
where the dependent variable EB represents the ecosystem benefits, the dependent
variable APB represents the agricultural productivity benefits, the dependent variable
MVB represents the agricultural land market value benefits, and RB represents the
recreational benefits. Cx is the acreage of land classified for a specific use (xl...xio), as
reported by each individual park/preserve manager (j) or agricultural manager (k). Each
x value corresponds directly to the land use classification listing from the survey, where
xl represents land used as park/preserve, x2 TepreSents right of way, x3 TepreSents
pasture/rangeland, x4 is crop land, x5 is fruit/citrus grove, x6 is nursery, x7 is forest, xs is
wetlands, x9 is lakeshore, and xlo is other uses. The variable M represents the total
management acreage reported by each park/preserve manager (j) or agricultural manager
(k), A is the acreage of Melaleuca treated as reported by each park manager (j) or
agricultural manager (k), and R is the effective rate of treatment. The variable I,
represents the percentage reduction in value reported averaged across responding park
and agricultural managers to ecosystem services, agricultural productivity, land market
value or recreational use of land reported by park managers (noted by the subscripts e and
r) and agricultural managers (noted by subscripts t, b, and m) as matched to the
corresponding equation. The variable F is the expansion factor used to expand the
sample results of agricultural managers to represent the entire population, Dx is the
ecosystem value adjusted for inflation from Costanza et al. (1997), P represents the
average market value (cash receipts per acre of land in agricultural production) of
agricultural products produced in the 10 county survey region, V represents the average
market value of land and buildings per acre in agricultural production in the 10 county
survey region, Y represents the total economic output of all of the state parks, and two of
the maj or national parks in the survey area, and L represents the total area of
park/conservation land in the 10 county survey region as reported by the Florida Natural
Areas Inventory (FNAI 2005).
In equation 5-1, the division of the Cx term by the M term yields the proportion
that indicates how much of the manager' s land area is devoted to particular uses. The
percentage this calculation yields is then multiplied by the acreage of2~elaletica treated,
represented by A, as reported by the park manager (j) and the agricultural manager (k).
This part of the equation is made necessary due to the fact that the professional managers
separately reported their land areas managed and the areas of2~elaletica that were
treated. That is to say, based upon the information gathered in the survey, there was no
delineation as to the land use classification of the infested area treated. Therefore, it
became necessary to make the assumption that the reported area of2~elaletica treated was
proportionally distributed among the nine possible land use designations reported by the
individual managers. For example, if a manager reported that they managed 120 acres of
pasture or rangeland and 30 acres of cropland, and that they treated 60 acres of2~elaletca
on their management site, then 48 acres of the M~elaletica was assumed to be treated on
rangeland while 12 acres was treated on cropland. This assumption allows for the areas
of~elaletica treated to be broken down by land use classification into the nine possible
classifications, which in turn, allows for an ecosystem function value to be properly
assigned to each land use classification. In equation 5-1 all land use classifications are
considered, due to the fact that most terrestrial areas provide some sort of ecological
function, even if it is somewhat diminished. The Costanza et al. value assigned to the
proper land use classification builds in an allowance for any diminished value in
ecological function. For example, the ecological function of cropland is only valued at
$108/hectare/year, while the function of wetlands is valued at $17,393/hectare/year.
As mentioned earlier, the tenacity of2~elaletica makes it difficult to kill. After
speaking with vegetation management experts from the South Florida Water
Management District and Everglades National Park, it was determined that the minimum
rate of kill to be reasonably expected after properly treating M~elaletica was
approximately 90 percent (Laroche and Taylor, pers. comm.). When contractors are
hired to go into an area and treat a Melaletica infestation, they are contractually obligated
to guarantee that the existing infestation will be reduced by at least 90 percent. Therefore
the R variable represents the effective rate of treatment and is a constant .90. This
adjustment is made to the area of2~elaletica treated, reported by managers, to allow for
the most realistic outcome of treatment to be represented within this benefit equation.
The variable Dx represents the ecosystem value described by Costanza et al.
(1997) that is assigned to the corresponding land use classification from the survey.
Costanza et al. report their values in 1994 U. S. dollars per hectare which were adjusted
for inflation to reflect current 2003 dollars using the GDP implicit price deflator 1.176 as
provided by the United State Department of Commerce (USDOC 2006). Additionally,
the treatment area figures reported by the managers in acres were converted to hectares.
Costanza et al. provides a value for land generally classified as terrestrial, but also
provides values for specific subcategories of land such as, forest, grass/rangelands,
wetlands, lakes/rivers, and cropland. The land use categories from the survey were
matched up with a terrestrial biome value so as to provide a dollar value per hectare for
the function of that ecosystem. Table 5-1 shows the Costanza et al. values adjusted for
inflation and assigns those values with the corresponding land use classifications from the
survey. As shown below, there are six possible amounts and they are applied to the 10
particular land use classifications reported by managers.
Table 5-1. Ecosystem Values for Surveyed Land Use Classifications.
Ecosystem Value adjusted Corresponding Land Use from
Classification for Inflation using Survey
Terrestrial 946 Right of way, Other
Forest 1,140 Park/preserve, Forest
Grass/rangelands 273 Pasture/rangeland
Wetlands 17,393 Mitigation area/constructed wetland
Lakes/rivers 9,997 Lakefront
Cropland 108 Crop, Fruit/citrus grove, Nursery
The next term, I (with the sub script e for park managers and t for agricultural
managers) represents the value for average negative impact to ecological function caused
by M~elaleuca as reported by professional land managers. In the surveys, managers were
asked to indicate how their operations had been negatively impacted in the areas of
agricultural productivity, land market value, ecological functions, and/or recreational use
as a result of~elaleuca infestations. None of the park/preserve respondents indicated
any negative impacts to the agricultural productivity or market value of their land.
Therefore, these negative impacts were not applied to any of the equations using their
information. The responses were then applied to the land use classifications and are
reflected in Table 5-2. Manager's perceptions are reflected by applying the average
negative impact percentage to the benefit gained by treatment of2~elaleuca on each land
use classification. This factor is an important addition because nobody knows the effect
M~elaleuca has on the land better than those who manage it and reflects the losses that can
be avoided by treating M~elaleuca.
Table 5-2. Average Negative Impact Values for Surveyed Land Use Classifieations.
Impact Average Average Reduction Corresponding
Reduction Park Agricultural Land Use
Managers (%) Managers (%) Classifieation
Reduced Agricultural N/A 24 Pasture, Crop,
Productivity Fruit, Nursery
Lowered Market N/A 11 Pasture, Crop,
Value Fruit, Nursery
Reduced Ecological 23 22 All Land
Diminished 23 25 Park/Preserve
Finally, the equation for agricultural managers also includes the term F which is an
expansion factor used only when applying the data collected for agricultural managers to
the equation. Since only a sample of agricultural managers were surveyed, it was
necessary to expand the sample results to represent the population of agricultural
managers in South Florida. Expansion factors can be devised based on either the land
areas surveyed or the number of people surveyed. In this case it was based on the
number of managers surveyed. The population was 1 1,500 and the sample size was
2,000. Dividing the population size by the sample size yields an expansion factor of
5.75. This calculation assumes that the sample data gathered was representative of the
Agricultural Land Productivity Benefits
Survey results indicated that only a small portion of the total area of2~elaleuca
treated occurs on agricultural land. However, in order to conduct a thorough analysis, as
many factors as possible are considered in calculating a benefit value. Equation 5-2 is
basically the same as the equation (5-1) used to calculate ecosystem benefits, with the
exception that the land areas reported and values applied are changed to reflect the effects
on agricultural productivity and not the ecological function and it only considers the data
gathered from agricultural managers. In essence the P variable replaces the value of the
ecological function seen in the ecosystem benefits equation and is equal to $1,034 per
acre as reported by the 2002 Agricultural Census data (USDA-NASS 2002).
Additionally, the average negative impact value, Ib, is reflective of the average
percentage reduction in agricultural productivity reported by agricultural managers
(24%), shown in Table 5-2. In this case only areas treated on agriculturally classified
land (range (x3), crop (x4), fruit (x5), or nursery (x6)) by agricultural managers are
considered since park/preserve managers reported that they managed very few acres of
land classified as being used for agricultural purposes.
Agricultural Land Market Value Benefits
A monetary value was estimated for the benefits accruing to agricultural land
market values due to the treatment of2~elaleuca on those agricultural lands. As is the
case with the previous equations (5-1 and 5-2) the variables in equation 5-3 are generally
the same; and this equation also considers only the data collected from agricultural
managers. Therefore, the areas reported for land uses Cxk, aCTOS ofhlelaleuca treated Ak,
total land management area Mk, and average negative impact value Im,(which is equal to
11% as shown in Table 5-2) are specific to agricultural managers and their perceptions of
the effects of2~elaleuca on land market values. Additionally, the variable V is equal to
$7,017 per acre, according the 2002 Agricultural Census data (USDA-NASS 2002).
Not only does land set aside as parks or preserves play an invaluable role in
allowing vital ecological processes to be carried out, but it also provides natural areas that
allow for humans to interact with nature and gain some measure of satisfaction from
recreation. Many individuals would probably indicate that the enj oyment they gain from
outdoor recreation is not completely attributed to the ecological functions taking place on
the land, and that some measure of enj oyment is gained from the existence of the land
and the availability of the land to provide them with a place to experience the outdoors.
Therefore, it is imperative to find a way to measure the recreational value that would be
lost due to a Melaleuca infestation on a park or preserve.
Equation 5-4 shows that the rate of treatment is found by dividing Cxy by Mj then
multiplying that by Aj, and by the effective rate of treatment R (0.9). The Y variable
represents the total economic output for the year 2003 of all of the state parks and two of
the maj or national parks (Everglades National Park and Big Cypress National Preserve)
in the survey region as generated by the Money Generation Model 2 (MGM2) and is
equal to $305,670,188 (MGM2 2003). Unfortunately, due to technical difficulties with
the website that publishes this information, at the time of this publication, the economic
output of other federal parks and preserves could not be collected. It is important to note
that the inclusion of the economic outputs of these other parks would drive the
recreational benefit value higher. The equation accounts for the percentage loss in the
recreational value of park/preserve land due to M~elaeluca infestation as reported by
professional park/preserve managers, therefore, the variable Ir is equal to 23%. Finally,
the previously discussed variables are all divided by the variable L which represents the
total area of park/conservation lands in the 10 county region for 2003 (5,275,455 acres)
as reported by the Florida Natural Areas Inventory (FNAI) located at Florida State
University (FNAI 2005).
The issue of Gire danger associated with dense M~elaleuca stands has been
documented over the years. The fire danger is not only a serious concern for the Florida
ecosystem, but also for the lives and properties that are threatened when a M~elaleuca
fueled fire occurs. Fire-fighting cost estimates have been compiled through suppression
bills issued by the Florida Division of Forestry (FDOF). In 1985 and 1989 M~elaleuca
fueled fires burned nearly 12,000 acres adj acent to the Dade County Northwest well Hield
at a cost of $25,000 and $21,000, respectively, and a 1,000 acre fire in Broward County
cost approximately $10,000 (Diamond et al. 1991). Costs for municipal fire departments
are estimated to be three times that of the FDOF due to their greater manpower
requirements and equipment expenditures (Wasil and Lewis pers. comm.). These
estimates yield a per acre cost of $2 to $10 for the (FDOF) and $6 to $30 for local
municipalities. When the median of the estimated cost ranges ($6 and $16) are used, and
applied to an assumed 12,000 acre fire the calculations yield cost savings estimates
(adjusted for inflation using the GDP implicit price deflator) of $97,207 for wildland fire
control by the FDOF and $259,219 for local municipal fire departments. Table 5-3
shows that the total benefits gained from treating Melaleuca in 2003 were $31,742,298.
The benefits that apply to the areas of land reported by park/preserve managers
are ecosystem benefits, recreational values, and the benefits gained from avoidance of
increased fire damages, which are $13.14 million, $9.17 million, and $178,213,
respectively for a total of $22.49 million. The benefits of restored ecological function,
agricultural productivity, agricultural market value, and avoidance of fire damages apply
to M~elaleuca treatment areas as reported by agricultural managers in the amounts of
$236,866, $2.15 million, $6.68 million, and $178,213, respectively, and yield a total of
$9.24 million. Since there are two categories of managers being considered, the overall
avoidance of fire damages AB ($3 56,426) is divided between the two categories to yield
$178,213 for each managerial category. Finally, the total benefits are reached by adding
equations 5-1 through 5-4, along with the additional benefits of fire prevention, together
(5-5) TB=EB + RB + APB + MVB + AB,
where TB stands for total benefits and AB stands for additional benefits due to fire
Table 5-3. Total Benefits of2~elaleuca Control in 2003.
Benefit Value ($)
Agricultural Productivity 2, 146,228
Agricultural Land Market Value 6,675,569
Ecological Function 13,397,685
Recreational Value 703,313
Avoidance of Fire damages 356,426
Calculation of Costs
The calculation of costs for this analysis is fairly straightforward since the cost
data were gathered by the survey. The following equations denote the different cost data
(5-6) Cp= E Hj,
(5-7) Ca= F E Zk,
(5-8) Cr= E Gi
(5-9) Ct= (CO3 CO4)/2,
where, the variable C, represents park manager costs and is equal to the summation of the
responses (Hj) of those managers, Ca represents agricultural manager costs and is equal to
summation of those responses (Zk), the variable F represents the previously discussed
expansion factor, and C, are estimated residential costs for the year 2003 based upon the
survey responses (Gi). The methods for that estimation are discussed below. The
dependent variable Ct is the TAME Mlelaleuca budget and the variables CO3 and CO4
represent the budgets for fiscal years 2003 and 2004 for TAME M~elaleuca.
When the survey responses for the cost Eigures of park/preserve managers were
summed it was calculated that they spent $10.87 million on M~elaleuca controls during
2003. The sample of agricultural managers surveyed indicated that they spent $204,790.
As mentioned earlier, assuming that the sample of agricultural managers is representative
of the population, this cost figure can be expanded to represent the whole population of
agricultural managers. This calculation reveals that the agricultural managers in South
Florida spent an estimated $1.18 million on M~elaleuca control in 2003. Additionally, the
TAME M~elaleuca program costs were reported as $820,000 for the 2003 Eiscal year
(October 1, 2002 to September 31, 2003) and $1,010,000 for the 2004 Eiscal year
(October 1, 2003 to September 31, 2004) (Silvers pers. com.). Since these fiscal years
divide up the calendar year 2003, half of each of the budgets was taken and added
together to yield $915,000 as the estimate for the 2003 TAME M~elaleuca budget.
Cost figures were also gathered from the residential surveys. However, the cost
data collected in this survey were gathered by asking respondents to indicate what range
of money they had spent on control measures from 1990 to 2003 or since owning their
property and were not as straightforward as the costs reported by the professional
managers. For example, instead of reporting that they spent $200 in 2003, residents
indicated that they spent an amount that fell within the range of $100 to $249 since
owning their property. These responses do not allow for a specific control cost figure to
be gathered for the year 2003 and require some additional assumptions and calculations
to be made. For the sake of clarity the two issues will be addressed separately.
Since the residential survey data was a sample gathered from the population the
sample data gathered needed to be expanded to represent the population of residents in
South Florida. The survey population was 2,511,141 and the sample size was 5,001.
Dividing the population size by the sample size yields an expansion factor of 502. 13. For
the sake of using a round number the expansion factor was rounded to 500 for the
residential data. Due to the fact that respondents indicated a range of money spent on
control efforts one specific Eigure could not be calculated. Instead three separate Eigures
were calculated to reflect a range of possibilities. Specifically, low, middle, and high
range estimates were calculated to demonstrate the possible outcomes for the responses
gathered. For example, if a respondent indicated that they qualified for the categorical
cost range of zero to $50, then the low, medium, and high range possibilities for that
respondent were zero, $24.50, or $49, respectively. Every person who responded to this
question was assigned a low, medium, and high range value. Each category's outcomes
were then summed together, thus allowing three different cost scenarios to be
demonstrated for residents.
These results indicate that $6,909, $31,029, and $68,808 were the raw results
from the estimation of the low, middle, and high range residential cost scenarios,
respectively. The low, middle, and high range numbers were then expanded to $3.45
million, $15.51 million, and 34.40 million, respectively, using the expansion factor of
500, as previously discussed. Due to the fact that the maj ority of residential respondents
responded that they did not have Melaleuca on their property the assumption was made
that most of the respondents who indicated the $0 to $49 range were most likely reporting
that they had spent $0 on control measures, so this analysis uses the low cost estimates.
Additionally, the cost figures must be adjusted to represent the time frame
addressed in this analysis. A value must be calculated from the data gathered to yield the
best estimate of the cost figures for 2003. Since the data reported were for a time span of
1990 to 2003 the figures computed above were averaged out over the 14 year period to
yield an average dollar amount spent per year. Using the low, middle and high range
scenarios as discussed above, residents are estimated to have spent $246,750, $1.11
million, and $2.46 million respectively on control measures during 2003.
Table 5-4 shows that an estimated total of $13,207,863 was spent on M~elaleuca
control measures in 2003. Therefore total costs (TC) are equal to the summation of
equations 5-6 through 5-9 and is demonstrated by:
(5-10) TC= C, + Ca + Cr + Ct.
Table 5-4. Cost Data for Melaleuca Control in 2003
Group Costs ($)
Park Managers 10,866,113
Agricultural Managers 1,180,000
TAME M~elaleuca 915,000
Calculation of the Benefit-Cost Ratio
Given the previous equations and methodology, the task of calculating a BCR that
compares agricultural productivity, agricultural land market values, ecological function,
and recreation benefits to control and program costs is now very simple. Using the
(5-11) BCR = TB/TC,
where the variable BCR represents the benefit-cost ratio and TB and TC represent the
total benefits and total costs, respectively, all that has to be done is to enter the
appropriate values into the equation to gain an overall BCR for treating Melaleuca. As
shown in the previous tables, the total benefits gained in the areas of agricultural
productivity, agricultural land market values, ecological function, and recreational
benefits from treating Melaleuca during the year 2003 equal $23,279,221 while the total
control and program costs from the same time period amount to $13,207,863. When
these values are applied to equation 5-11, the results yield a benefit-cost ratio of 1.76.
While the total benefit-cost ratio is useful in helping to determine the overall
success or failure of a program, the discussion of the benefit-cost ratios from the
subcategories considered in this analysis can also be useful. The categories of survey
respondents had very different results for the areas occupied by M~elaleuca and the areas
treated. When the same methodologies used for the overall benefit-cost ratio are applied
to the subcategories of data, separate benefit-cost ratios can be determined for
park/preserve managers and agricultural managers. The total benefits accruing to
park/preserve managers are $14.02 million, while the total costs park/preserve managers
reported in the survey were $10.87 million, thus, yielding a benefit-cost ratio of 1.29 for
Total benefits accruing from treatment of2~elaleuca on agricultural land are
estimated to be $9.24 million. When the cost data reported by agricultural managers are
expanded to represent the population it is estimated that the total costs were $1.18
million. Using equation 5-1 1, the calculation reveals a benefit-cost ratio of 7.83. This
number is relatively high due to the fact that agricultural lands have multiple benefits
accruing to them. Agricultural managers also reported lower costs because they have not
been treating M~elaleuca as aggressively as park managers and therefore have a greater
marginal value response at this stage of their control efforts. If agricultural managers
pursue controls more assertively, it is expected that the marginal value of the benefits
from their control efforts will diminish with the greater treatment area. While
park/preserve lands also have the multiple benefits of ecological function and recreational
value, agricultural lands have agricultural productivity and land market values as well as
ecological function accruing to them. Even though the ecological benefits that accrue to
agricultural lands are greatly diminished as compared to lands held in a natural state, the
soil and bedrock contained in them still serve some water filtration purposes, however
minimal. Therefore, agricultural lands have a relatively larger amount of benefits
accruing to them than park/preserve. While the previous statement may be true for the
purposes of this analysis, it is imperative to not jump to the conclusion that agricultural
lands are simply more valuable than park/preserve lands. There are benefits such as
existence values for parks/preserves that are not considered in this particular analysis and
would undoubtedly drive the benefits accruing in those areas higher.
SUMMARY AND CONCLUSIONS
This thesis seeks to characterize the current state of the management of2~elaleuca
in South Florida and determine the benefits and costs of controlling M~elaleuca for the
year 2003. Previous benefit-cost analyses have primarily focused on the possible benefits
and costs associated with the unfettered spread of2~elaleuca. That kind of research was
quite useful in helping to determine if the benefits to undertake control strategies would
outweigh the costs. This analysis differs in that it seeks to assign a monetary value to the
benefits actually gained on the areas of land invaded by Melaleuca which have been
successfully treated and the costs associated with that treatment. Instead of conducting
an analysis that assumes a hypothetical best or worst case scenario, this analysis seeks to
focus on the reality of what is actually happening with the spread and treatment of
M~elaleuca in South Florida and serves to evaluate policy and management decisions
made during this program.
After consultations between UF-IFAS, USDA-ARS, and TAME M~elaleuca,
surveys were developed and mailed to professional land managers and residents in the 10
southernmost counties of Florida during the summer of 2004. The surveys for the
professional managers were sent to individuals whose management areas were classified
as park/preserve or agricultural. A wealth of information was gathered to help gain
insight into the current status of the war against M~elaleuca. The benefit-cost analysis
specifically used the data that pertained to the land use classifications of the management
area, how much M~elaleuca was on the land, the area of2~elaleuca treated, the costs
associated with the treatment, and the negative impacts to the land caused by the
M~elaleuca infestations as estimated by managers. The response rates for park/preserve
and agricultural managers were 32% and 22%, respectively.
The responses from park/preserve managers revealed that 619,317 acres of
M~elaleuca inhabited their management areas, while they treated a total of 84,740 acres
during 2003. Based on the fact that control strategies are not completely effective, a 90%
rate of effective removal was applied to the treatment areas reported by park/preserve
managers to yield the estimated area of Melaleuca killed as 76,265 acres. The total costs
associated with these control methods were reported as $10.9 million. The park/preserve
managers felt that M~elaleuca impaired the ecological function and recreational use of the
land they managed by an average of 23%.
Agricultural managers indicated that a total of 2, 134 acres of~elaleuca occurred
on their land and that they treated approximately 1,991 acres during the year 2003. When
the assumed effective rate of treatment is used it is estimated that approximately 1,701
acres of Melaleuca were killed on agricultural lands during 2003. The total costs
associated with these treatments were approximately $204,790. It should be noted that
these figures collected from the sample of agricultural managers were expanded to reflect
the population for the calculation of the benefit cost ratio(s). The expanded figures
indicate that agricultural managers had an estimated total of 12,271 acres of2~elaleuca
occupying their land, while they treated an estimated 10,868 acres at an estimated cost of
$1,180,000 during 2003. Finally, the agricultural managers reported that the agricultural
productivity, market value, and ecological function of their land had been reduced by an
average of 24 percent, 11 percent, and 22 percent, respectively.
The maj ority of the data gathered by the residential survey was directed at
gathering information related to the awareness and perceptions of2~elaleuca by the
residents and therefore much of it was not used in this benefit-cost analysis. However,
the cost data collected from the residents was used. Residents had the lowest survey
response rate at 20 percent. Based on the data collected and the methods described in the
previous chapter, it was estimated that the residents of South Florida spent an estimated
$246,750 on Melaleuca control/removal in 2003.
Using the information gathered from the mail surveys and other relevant data
sources it was determined that the benefit-cost ratio for M~elaleuca control in the year
2003 was 1.76. The benefit portion of the ratio was computed by assessing monetary
values for the benefits that were gained due to the restored ecological function of
agricultural and park/preserve land, agricultural productivity and market value of
agricultural land, and the recreational use of park/preserve lands where M~elaleuca
controls had been implemented. The additional benefit of avoidance of costs connected
with M~elaleuca fueled fire control was also considered in the benefit equation. The costs
were derived from the residential and professional survey data along with the TAME
M~elaleuca program costs which include the costs associated with this research.
Conclusions, Implications, and Policy Recommendations
Based upon the results of the surveys it is quite apparent that the vast maj ority of
M~elaleuca control is still taking place on public land in South Florida. As stated in the
introduction of this thesis, this phenomenon is most likely due to the fact that a legal
mandate requires public agencies to remove invasive plants from their management areas.
It may be necessary for the legislature to make the current laws addressing the general
public more stringent so as to induce a greater number of private land managers and
homeowners to implement M~elaleuca controls on their properties. While making the
laws stricter is a step in the right direction, it will also be necessary for the lawmakers to
assign specific penalties for those in violation of the law and require a uniform
enforcement of the laws and penalties. This would require increased presence by the
enforcement agencies and would certainly require a greater amount of time and effort
from those agencies. A requirement similar to those municipalities that call for new
construction sites to have Melaleuca trees removed from the property before a certificate
of occupancy can be issued may be a useful tool in inducing Melaleuca removal.
The results of the benefit-cost analysis support the earlier hypothesis made that this
analysis would yield a benefit-cost ratio higher than one. When the benefits from
M~elaleuca control realized on park/preserve and agricultural land are compared to the
costs incurred by those land managers and private residents the analysis indicates that the
benefits are almost two times greater than the costs. It is important to keep in mind that
this is not even considering benefits that may be accruing to the private homeowners in
South Florida and would only serve to increase the benefits. Given the resulting cost-
benefit ratio of 1.76, it can be said that the current policy requiring M~elaleuca control is
providing a benefit to society in the year 2003. It is interesting to note that due to the
compound effect of having multiple values tied to their land (i.e.-the values gained from
the ecological functions, the actual production of agricultural commodities as well as the
market value of the land) this analysis indicates that agricultural lands have a higher
benefit-cost ratio than park/preserve lands for treating M~elaleuca (7.83 vs. 1.29). Even
without considering the benefits accruing to agricultural land market values, the ratio is
still greater for agricultural lands than park/preserve lands (2.17 vs. 1.29). Therefore it is
recommended that policymakers and public agencies continue to at least maintain the
current levels of funding and control efforts for M~elaleuca reduction. Not only should
they continue to maintain the current levels of funding, but they should also consider
increasing funds to help specifically target agricultural managers to persuade them to
control M~elaleuca on their property. This would serve to help solve the problem of
having M~elaleuca spread around private lands, while it is being controlled on public
lands, and would also help avoid cross contamination from the infested areas to the areas
A maj ority of residents who responded to the survey questions aimed at
determining their awareness of2~elaleuca indicated that they knew that M~elaleuca was
not native to Florida and that they knew non-native plants could be harmful (71% and
89%, respectively). However, when the residents were later asked to indicate if
M~elaleuca effected their enj oyment of the outdoors 77% of those who responded to the
question indicated that it did not. When residents were asked to indicate if they felt that
M~elaleuca negatively affected their property value 95% of those responding to the
question indicated that they felt it did not. There seems to be a gap between what people
know about M~elaleuca and how that knowledge affects their desire to take the actions
necessary to control it. According to the survey data the main sources that provide
information on M~elaleuca for residents were newspapers and local/national news (59%
and 47% of residents who responded to the question, respectively). These may be the
outlets that policy makers, environmental action groups, and public agencies should