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Patrick J. Minogue, Holly K. Ober, and Stanton Rosenthal2 1. This document is FOR125, one of a series of the School of Forest Resources and Conservation Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date August 2007. Reviewed November 2010. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. Patrick Minogue (Pat) is an Assistant Professor of Silviculture and Holly Ober is an Assistant Professor of Wildlife in Forests, The University of Florida, IFAS, at the North Florida Research and Education Center, 155 Research Road, Quincy, FL 32351-5677. Stanton Rosenthal is Leon County Forester, 615 Paul Russel Road, Tallahassee, FL 32301-7060. The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. Pine straw is a popular mulch in residential and commercial landscaping for its color, easy placement, and cost. Pine straw raking in Florida is a relatively new enterprise, but as of 2005 it has grown to be a 79 million dollar industry, which is about the same as the value of pulpwood in our state (Hodges et. al 2005). Pine straw moves to market in a variety of ways but the most common is for a pine straw company to pay an annual lease to take the straw. Annual leases may range from 70 to more than 100 dollars per acre, representing substantial potential revenue for landowners. Old field plantations are favored for pine straw raking because their relatively clean understory facilitates raking straw. Credits: Pat Minogue, 2007. Longleaf pine and slash pine are the favored southern pine species because their long needles bail well. Pine needle raking may begin when stands are as young as eight years old, when pine needle yield is expected to be between 100 and 150 bales per acre. Maximum pine needle yields occur at about age fifteen when between 200 and 300 bales per acre can be obtained (Duryea 2003). Pine straw must be free of fallen branches, pine cones, twigs, and other vegetation (Figure 1). Prior to raking a cleanup is needed to place debris into piles and often to control groundcover or understory vegetation to facilitate
Overview of Pine Straw Production in North Florida: Potential Revenues, Fertilization.... 2 raking clean straw. Pine straw companies normally provide this service and lease the area to rake for several consecutive years. When selling pine straw to a producer it is wise to obtain competitive bids. Pine straw yields change as the trees age so consider the stand age in pricing. Pine needles fall all year but the greatest needle drop occurs from September through November, so one of the best times to rake is in the winter. Old field plantings or plantations on cutover sites where competing vegetation is controlled intensively are best suited to clean pine straw production. On cutover sites, vegetation control should begin with site preparation using machinery, herbicides, fire, and various combinations of these treatments prior to planting (Lowery and Gjerstad 1991). After plantation establishment, selective herbicides, which are safe to pines, may be used to remove hardwood trees and brush (Minogue et al. 1991) facilitating raking the ground and limiting the amount of litter from deciduous trees and shrubs. Most techniques involve treating individual hardwood trees or shrubs with hand-held tools, back-pack sprayers, and small machinery such as 4 wheel drive, all-terrain-vehicles and small tractors. Broadcast applications using ground machinery or helicopters may also be done to control hardwoods in established stands. Some of the most common treatments include back-pack foliar sprays, basal stem treatment, cut-stem treatment, soil spot application, and broadcast application. These are chosen largely based on the size and density of stems to be removed. Where sapling size hardwoods, less than head tall, are to be controlled, back-pack sprayers can be used to direct herbicide spray to the foliage of undesirable brush and sapling trees. Many herbicide products are available for this use, but combinations of Roundup (glyphosate) and Arsenal Applicators Concentrate (or Chopper) (imazapyr) are most cost-effective across a wide range of brush species. A common mixture is 2% Roundup plus either 0.5% Arsenal or 1% Chopper in water. Add 1%-5% methylated seed oil surfactant to improve control, particularly when treating oaks and other species with a thick cuticle (leaf covering). The oil improves penetration into the leaves and fosters good control. Apply this mixture to at least 2/3 of the crown with light coverage; there is no need to wet the foliage. Late summer to the beginning of fall coloration is the ideal timing. Refer to directed foliar sprays on the product labels for additional information. Where undesirable hardwood crowns are too tall to reach with a backpack sprayer, or where very numerous sapling size stems are present, consider using a basal stem treatment with Garlon 4 (triclopyr). There are several approaches described on the product label, but essentially a mixture of herbicide in oil is applied to the basal (lower) portion of the stem. It is best to treat the root collar, the base of the trunk where it goes into the soil. The approach is most effective on stems less than six inches in diameter, and is suggested for stems less than three inches. Thin-barked species are easier to control. The cut-stem method discussed below is typically used for larger diameter stems. Basal stem treatments may be done anytime of year, including winter. Applications are made using a straight-stream sprayer such as the Gunjet applicator or a simple squirt bottle. Velpar L (hexazinone) may be applied directly to the soil surface to control susceptible species either by treating the soil at the base of individual stems, or when brush is dense, by making applications in a grid pattern. When labeled rates are applied, pines are tolerant to this herbicide. The amounts of product will depend on the hardwood species, stem diameter, and soil texture; see the product label for details. Undiluted product may be applied with a squirt bottle or by more durable equipment such as a MeterJet. Optimum timing is from spring bud break to early summer. Rainfall is needed to foster root uptake. Hexazinone is most effective on sandy soils and is particularly effective for controlling oaks.
Overview of Pine Straw Production in North Florida: Potential Revenues, Fertilization.... 3 A hatchet and squirt bottle may be used to apply small amounts of herbicide directly into the vascular system of undesirable hardwoods. This approach is most appropriate where there are few scattered individuals with diameters greater than 3 inches. Many products are available for this use, but the most popular are Arsenal Applicators Concentrate (imazapyr) and Garlon 3A (triclopyr) which are mixed with water or used undiluted. A hatchet is used to cut through the bark in a downward fashion to create a cup in which to place a small amount of herbicide solution, one milliliter or about the amount a typical squirt bottle produces with one pull. Cuts are made around the stem to encircle the stem at a convenient height and different approaches regarding the distance between cuts and solution concentration to use are described on the product labels. From experience, we know to use a sharp hatchet to ensure a deep cut past the bark and well into the wood. Place only as much herbicide solution as will remain in the cut. Imazapyr is the treatment of choice for this purpose because of its effectiveness over a broad spectrum of species and low use rate. Either imazapyr or triclopyr may be applied throughout the year with good results, except during the period of strong sap flow in the early spring. For imazapyr fall applications are optimum. Several herbicides may be broadcast by ground or aerial equipment to selectively remove hardwood trees and brush in southern pine stands. The most common materials are Arsenal Applicators Concentrate (imazapyr) and solid formulations of hexazinone (Velpar ULW, and Pronone 10 G). Imazapyr is applied in the late summer and early fall as a foliar spray and is effective on a wide range of hardwood species with some notable exceptions including winged elm and redbud. Hexazinone products are applied from spring bud break to early summer and are very effective in controlling oaks. Both products will also control herbaceous vegetation. Many non-selective herbicide treatments may be applied as a directed spray to target the foliage of undesirable vegetation in pine stands, but pine injury will occur if the pine foliage is sprayed or affected by the herbicides vapors (volatility). Perennial grasses such as Bermuda grass and Bahia grass are often a problem on old field sites until some time after crown closure when light excludes them. A directed application of 2% Roundup (glyphosate) during periods of active growth in the spring is a simple solution to this problem, but be sure to keep it off the foliage of trees or any other desirable vegetation or injury will occur. Chopper may only be used below the pine canopy and is most effective when applied in an emulsion using methylated seed oil. Garlon 4 is particularly effective on flatwoods vegetation such as gallberry (Ilex glabra) and saw palmetto (Serenoa repens) but it must be applied below the canopy of pines and volatility may result in injury when applied on warm days. Please see label directions for more details on these treatments. Pine needles fall all year but the greatest needle cast occurs from September through November, so one of the best times to rake is in the winter. Pine straw harvesting may be done by hand with rakes or with machines that rake straw into windrows. In either case needles are placed into box or round bailers with a pitchfork or by hand. With hand-raking an individual may bail between 100 and 200 bales per day. Using machinery a three person crew can produce 250 to 300 bales per day (Stanton 1986), but there is some concern regarding stem and root damage in the stand with machinery. Pine straw serves many important purposes in the tree stand and there are concerns that its removal can have detrimental effects on tree growth. Pine straw plays an important role in supplying nutrients for tree growth, and each year a large portion of the nutrients absorbed by trees is returned to the soil via pine needles. As these needles decompose they provide nutrients for uptake by tree roots and thus, are a part of the nutrient cycle in forest stands (Switzer and Nelson 1972, Jorgensen and Wells 1986). Nutrients can be replaced by fertilization, but pine straw also has an important effect on soil moisture,
Overview of Pine Straw Production in North Florida: Potential Revenues, Fertilization.... 4 improving water infiltration and reducing evaporative water loss in much the same way as it does when used in ornamental applications as mulch. Decomposing pine needles add to soil organic matter thus improving nutrient availability and soil water-holding capacity. Removing pine straw can increase tree water stress on dry sites (McLeod et al. 1979, Ginter et al. 1979), and can also increase soil bulk density (Haywood et al. 1998). In the Sand Ridge region there are large areas of deep sand, excessively drained soils with little soil profile development (CRIFF group G), where silvicultural practices should strive to maintain soil organic matter, thus providing better soil moisture availability and tree nutrition (Jokela and Long 2000). Pine litter also protects the soil from erosion, improves water infiltration (Pote et al. 2004), insulates against rapid temperature changes, and provides habitat for some animals. Because of these important benefits of pine litter in the forest, it is recommended that pine straw should not be removed more than five times during the stands life (Duryea 2003). Fertilizers are commonly applied in southern pine stands at establishment or periodically during the rotation to increase financial returns by enhancing growth rates and shortening the time to harvest (Jokela et. al 1991, Jokela and Stearns-Smith 1993). Mid-rotation fertilization as a means to enhance pine straw production, replace nutrient removals, and foster timber growth is very common. Nitrogen (N) and phosphorus (P) and potassium (K) nutrient removals from pine straw raking are largely a function of the proportion of the harvestable area, site, and stand conditions; but for a single raking range from 5-60 lb N, 0.5-5 lb P, and 0.5-29 lb K per acre (Morris et al. 1992). Prior to fertilization a soil test should be made to identify inherent fertility and nutrient needs. Growers typically apply 150 to 200 pounds of nitrogen, 50 pounds of phosphorus, and 50-80 pounds of potassium per acre using mineral fertilizers such as diammonium phosphate (N+P), ammonium nitrate and urea (N), triple supper phosphate and ground rock phosphate (P), and KCl (muriate of potash) or KSO4 (potassium sulfate)(K). Nutrient use efficiencies for fertilization of southern pines are typically about 50% (Morris et al. 1992), but are expected to be less on the excessively drained sand ridge sites of the region. Sandy soils have low cation exchange capacity and low soil organic matter so they do not hold nutrients well. Water deficits generally limit pine productivity and responses to fertilizers on excessively drained soils. Additionally, when fertilizing these soils the potential for leaching and groundwater contamination is a concern (German 1997). Morris et al. provide specific fertilization recommendations for old field or cutover sites, different stand ages, raking frequencies, and various site types, but they do not recommend fertilization for sandhill sites characterized by soils with surface horizons greater than 40 inches deep without fine textured subsoils. Follow pesticide BMPs to protect water quality and aquatic life. Choose equipment that directs the chemical only to the target area. Do not conduct aerial application or mist blowing of pesticides or fertilizers within any part of the Primary Zone. For perennial streams, the Primary Zone is an untreated buffer on both sides of the stream 35 to 200 feet wide depending on the width of the stream (Anonymous 2004). Do not leave pesticide containers on-site. Do not rinse spray equipment or discharge rinse water in water bodies, wetlands, or within the Special Management Zone (the buffer around water bodies). Existing silvicultural fertilization BMPs recommend developing a nutrient management plan based on soil, water, plant and organic material sample analysis and consideration of expected or desired timber yields to supply nutrient inputs efficiently, so that the benefit of fertilization is captured by target vegetation and the adverse effects to water resources are minimized.
Overview of Pine Straw Production in North Florida: Potential Revenues, Fertilization.... 5 Do not apply fertilizer or locate fertilizer transfer/loading areas within the Primary Zone of the Special Management Zone (SMZ). Whenever practical, apply fertilizer to maximize the uptake of nutrients. Do not exceed the maximum amounts of fertilizer specified by BMPs. Elemental Nitrogen: No more than 1000 lb per acre over any 20-year period No more than 250 lb per acre for any 3-year period No more than 80 lb per acre during the first two years after planting Elemental Phosphorus: No more than 250 lb over any 20-year period No more than 80 lb over any 3-year period Anonymous, 2004. Silvicultural best management practices. Florida Department of Agriculture and Consumer Services. 98 p. Duryea, M. L. 2003. Pine Straw Management in Florida's Forest. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, The University of Florida, Circular 831. 6 p. German, E.R. 1997. Analysis of non-point source groundwater contamination in relation to land use: Assessment of non-point source contamination in central Florida. US Geological Survey Water-Supply Paper 2381-F. Ginter, D.H., K.W. McLeod, and C. Sherrod, Jr. 1979. Water stress in longleaf pine induced by litter removal. For. Ecol. Manage. 2:13-20. Haywood, J.D., A.E. Tiarks, and M.L. Elliott-Smith. 1998. Response of direct seeded Pinus palustris and herbaceous vegetation to fertilization, burning, and pine straw harvesting. Biomass and Bioenergy. 14:157-167. Hodges, A.W., W. D. Mulkey, J. R. Alavalapati, D. R. Carter, and C. F. Kiker. 2005. Economic impacts of the forest industry in Florida, 2003. The University of Florida, Institute of Food and Agricultural Sciences. Final Report to the Florida Forestry Association. 3 pp. Jokela, E.J., H.L. Allen, and W.W. McFee. 1991. Fertilization of southern pines at establishment. Chapter 14 In Forest Regeneration Manual, M. Duryea and P. Dougherty (eds.). Kluwer Acadedimic Publishers, Dordrecht, Netherlands. Pp 263-277. Jokela, E.J. and S.C. Stearns-Smith. 1993. Fertilization of established southern pine stands: Effects of single and split nitrogen treatments. South. J. Appl. For. 17:135-138. Jokela, E.J. and A.J. Long. 2000. Using soils to guide fertilizer recommendations for southern pines. University of Florida. Institute for Food and Agricultural Sciences. Circ. 1230. 13 pp. Jorgensen, J.R. and C.G. Wells. 1986. Foresters primer in nutrient cycling. USDA Forest Service Gen. Tech. Rpt. SE-37. 42 pp. Lowery, R.F. and D.H. Gjerstad. 1991. Chemical and mechanical site preparation. Chapter 13. In Forest Regeneration Manual. M. Duryea and P. Dougherty (eds.) Kluwer Academic Publishers. Dordrecht, Netherlands. Pp 335-358. McLeod, K.W., C. Sherrod, and T.E. Porch. 1979. Response of longleaf pine plantations to litter removal. For. Ecol. Manage. 2:1-12. Minogue, P. J., H. C. Griswold, and R. L. Cantrell. 1991. Vegetation management after plantation establishment. Chapter 19. In Forest Regeneration Manual. M. Duryea and P. Dougherty (eds.) Kluwer Academic Publishers. Dordrecht, Netherlands. Pp 335-358. Morris, L.A., E.J. Jokela, and J.B. O'Connor, Jr. 1992. Silvicultural guidelines for pinestraw management in the southeastern United States. Georgia Forestry Commission. Georgia Forestry Research Paper No. 88. 11 pp.
Overview of Pine Straw Production in North Florida: Potential Revenues, Fertilization.... 6 Pote, D. H., B. C. Grigg, C. A. Blanche, and T. C. Daniel. 2004. Effects of pine straw harvesting on quantity and quality of surface runoff. Journal of Soil and Water Conservation 59:197-204. Stanton, W. M. 1986. Longleaf pine straw production. Woodland Owner Notes. North Carolina Agricultural Extension Service, Raleigh, North Carolina. No. 18. 4 p. Switzer, G.L. and L.E. Nelson. 1972. Nutrient accumulation and cycling in loblolly pine (Pinus taeda L.) plantation ecosystems: the first 20 years. Soil Sci. Soc. Amer. Proc. 36:143-147. The University of Florida, Institute for Food and Agric. Sciences http://edis.ifas.ufl.edu PLEASE, READ AND FOLLOW ALL HERBICIDE LABEL DIRECTIONS Roundup is a registered trade mark of Monsanto. Chopper and Arsenal Applicators Concentrate are registered trade marks of BASF. Garlon 4 and Garlon 3A are registered trade marks of Dow Agrosciences, LLC. Gunjet and Meterjet are registered trade marks of Spraying Systems. Velpar L and Velpar ULW are registered trade marks of DuPont. Pronone 10 G is a registered trade mark of ProServe.