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Title: Producing tung oil in Florida
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Title: Producing tung oil in Florida
Physical Description: Book
Creator: Stoutamire, Ralph.
Publisher: Dept. of Agriculture,
Publication Date: 1935
Copyright Date: 1935
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Full Text

New Series No. 11




Ralph Stoutamire

NATHAN MAYO, Commissioner
August, 1935.



Introduction -...--.--_.... ......------- ------- 5

Introduction Into Florida .6-- --- -- G

The Oil and Its Uses .._--- 6

Market Demands S----.---------------- ----- ------ 8

The Tree and Its Fruit ---- --- -- 9

Acreage and Distribution ----- 10

Soil Considerations ..---- --- 12

Selecting Seed ---_ ----13

Culture and Fertilization _-.- --- 13

Planting and Maintenance Costs ._ --- --- 16

Yields and Profits .------- 17

Pests .----.- --- ....------------ ---- 18

Acknowledgements .--------- 18

Locations of Plantings --------- 20

Potential Areas of Cultivation --------23

Soil and Drainage Requirements -_----- 24

Status of Grove Development --------27

Plantings in Florida --------- ------- 27

Uses of Tung Oil ..----------------------------- 30

Acres in Tung Trees by Counties ---_ -- -- 31


By Ralph Stoutamire

NEW CROP is bidding for a place in Florida's agri-
culture. It is tung oil and it now appears that before
long this new crop will be bringing in an attractive
revenue to growers in those localities of the state adapted to
its growth. The introduction of no plant in recent times has
created such widespread interest as has that of tung oil.
This interest is due, naturally, to the great promise to
America of the production here of a commercial oil which
heretofore has been produced only in the Orient but which
is utilized in both American and European industries in
large and increasing quantities.
Because of the wide consumption and diversified uses of
tung oil, the questions of demand or over-supply and market-
ing at this time offer little concern. Methods of oil extrac-
tion having been successfully determined, and the purity,
quality, and superiority of the American product having
been amply tested and demonstrated, the present problems
of tung oil production are mainly cultural. As the tree has
been under cultivation in America but a relatively short
time, much yet has to be learned as to its soil and climatic
adaptability, its varietal differences, and its fertilizer and
other general requirements.
However, enough general information has been gained
that we may say the experimental stage has been passed.
With properly selected plants grown on suitable soil and
with the best known cultural practices, successful and sub-
stantial production is no longer considered a possibility but
an attained reality.

Early in the present century, officials of the United States
Department of Agriculture-notably Dr. David Fairchild,
senior agricultural explorer-realized the importance and


value of tung oil. In 1905 Dr. Fairchild, with the assistance
of L. S. Wilcox, United States counsel general at Hankow,
imported seed for trial planting in America. Those seed
were planted in Chico, California. In 1906 the seedlings
therefrom were distributed to experiment stations and
collaborators in southern and southwestern states. The
results of this distribution after some twenty years, demon-
strated that plantings in Florida had made the most satis-
factory growth and yields.

A single tree planted near Tallahassee, seems to have
been the only one to survive of those grown from the origin-
al introduction into Florida. It was from seed of this tree
that the first tung oil was extracted in America. A later
planting of several trees was made on the grounds of the
State Experiment Station at Gainesville. These early plant-
ings in northern and north central Florida have, by growth,
and yield, given evidence that the climate and certain soil
types here are optimum for the successful growth of tung
oil trees. That evidence has resulted in the present commer-
cial plantings in the state, the first of which was made in
Alachua County in 1924. Since that time plantings have
steadily increased to bring the present acreage in Florida
to approximately 10,000.

In line with the development of the industry, a modern
and complete oil expressing plant was erected and placed in
operation near Gainesville in 1928. This plant means that
the grower now has a ready cash market for his crop.


Tung oil, also called wood oil or China wood oil, is that
removed from the seed of the tung oil tree. The oil yield is
about one-third by weight from air-dried seed and about
one-fifth by weight from air-dried whole fruits.

Before pressing, the oil in the seed is almost colorless,
the depth of color in the expressed oil depending in part on
the method used in extraction. American oil has a very
light amber or straw color and a very low acid content,
while Chinese oil is much darker and has a high acid con-
tent. Both chemical and mixing tests have demonstrated the
superiority of the American product. Crude hand methods
and hollow-log processes, operated by hand and by awk-
ward manipulation of wedges, are used in China. It is said


the American method of extracting the oil results in a saving
great enough, over the crude Chinese method, to more than
pay for the cost of our extracting machinery and for the
extracting operation. One man can operate our machine
which does the work-and does it better-of perhaps a
thousand Chinamen. The Chinese method, with its accom-
panying lack of efficiency, and a complicated system of oil
collection, results in an oil varying in degree of purity and
quality. Frequently it is greatly adulterated with inferior

There are three methods of oil extraction-namely, by
volatile solvent, by hydraulic press, and by screw press or
expeller. By comparative tests the expeller method has
proved best from standpoints of both economy and effi-
ciency. This is the method employed by the plant at Gaines-
ville. The oil-expressing operation is continuous and almost
wholly mechanical. The air-dried whole fruits are decorti-
cated by a combined huller-separator. The seed are then
conveyed to a grinder which converts them into a coarse
meal. This meal is in turn fed into the expeller which by
pressure extracts the oil. Further treatment of the oil,
other than settling, is not required; it is now ready for
storage or immediate use.

Tung oil has a wide variety of uses. In China it is used
extensively to waterproof paper, cloth and masonry, as well
as a varnish. In America it is usedn-iainlyin varnishes,
being combined with rosin to form a combination that has
entirely replaced the imported fossil gums. Further uses-
other than in waterproof varnishes and paints, all of which
require large quantities-are the insulation of electrical
equipment, as wires, cables and motors; the manufacture of
linoleum and oilcloth; leather dressing; sheet packing and
gaskets; and automobile brake linings. Paint and varnish
manufacturers use the oil as a necessary ingredient in an
extremely wide variety of their products, inc4ding lacquers,
japans, enamels, fillers, hardeners, insulating and impreg-
nating compounds, finishers, sizings, and numerous others.
They also use tung oil in their many paints and varnishes.
The pomace or seed cake, which is left when the oil is
extracted, contains about 6 percent of ammonia, and com-
pares favorably in analysis with castor pomace. This ma-
terial, therefore, has value as a fertilizer.. The hulls can be
used to advantage for mulching purposes.


Tung Oil Tree In Bloom


During 1929 over 119,000,000 pounds of tung oil, valued
at about $15,000,000, were imported to supply the demands
of the American markets. This amount was nearly three


times that imported in 1918. The average valuation per
pound in 1929 was 121/2 cents. Among chemical importa-
tions into the United States tung oil has attained fourth
place in importance. Europe is also using the oil in large
quantities. Figures showing the remarkable increase in
American imports from 1920 to 1929 are shown below:

Year Pounds Value
1920 45,232,000 not given
1921 27,249,000 $ 2,470,000
1922 79,089,000 7,891,000
1923 87,292,000 13,397,000
1924 81,588,000 11,092,000
1925 101,554,000 11,386,000
1926 83,004,000 9,148,000
1927 89,650,000 11,810,000
1928 109,222,000 13,419,000
1929 119,678,000 14,972,000

Manufacturers, assured of a steady and increasing supply
of American oil, will utilize it in greater quantity and in a
wider variety of products. There is now good reason to
believe that tung oil when available in sufficient amounts,
will to a degree supplant linseed oil in many ways. That
this will open a wide market is shown by the fact that close
to $60,000,000 worth of linseed oil is imported into this
country every year. The United States produces only about
half of the linseed oil used by its own industries and con-
sumers. From the above figures it is apparent that the
demand for tung oil is already developed and it would
appear that any question of over-production is so far in the
future as not to be considered.

The tung oil tree belong to the Spurge family and is
botanically classified as Aleurites fordi, known to the China-
man as Tung-yu-shu.

The mature tung oil tree is about 30 or 35 feet high and
it spreads in all directions equally. It is deciduous, dropping
its leaves in November and leafing out in March or early
April. The blossoms, appearing with or before the leaves,
are of two kinds-staminate and pistillate. Both types of
blossoms are born on the same tree. Therefore, any tree is


In China the tree is said to have a life of from 30 to 50
years. There is no means of knowing how long it will live
in the Florida environment, but there is no reason to believe
that its length of life will be less than in China. Florida's
first planted tree, despite neglect and damage from fire, has
passed the quarter-century mark and is still producing.

The fruits, commonly but improperly called nuts, ripen
in October and November. When mature they drop from
the tree which obviates the necessity of picking and mark-
edly decreases harvesting costs. The appearance and shape
are somewhat like that of a small apple, the diameter being
from two to three inches and the color olive green. The
color becomes brown at maturity. Normally there are five
seed in each fruit. The hull is tough and leathery and be-
comes quite hard when thoroughly air-dried.

There are as yet no named varieties, although several
variations among seedling trees are apparent. These dif-
ferences have to do mainly with the size and shape of the
fruit, variation in leaf shape and blossom color, and the
number of individual fruits born at the twig end. The last
has led to the general designation of two types-single and
cluster. If cluster bearing proves an inherent character-
istic, as now appears to be the case, it will be advantageous
to plant this type so as to secure heaviest yields.-


At the end of the 1930-31 planting season the plantings of
tung oil trees in Florida closely approximated 10,000 acres,
an increase of over 4,000 acres over the previous year's

Plantings extend from Polk to Escambia Counties with
the major part of the acreage located in Alachua, Levy,
Clay, Lake and Okaloosa Counties. Alachua leads with
approximately three-fifth of the state's total, or approxi-
mately 6,000 acres. Numerous smaller plantings are to be
found in many other counties.

In addition to field plantings a considerable acreage is
devoted to the growing of nursery stock. Planters who do
not wish to grow their own planting stock or who are
desirous of saving a year's time in planting a grove may buy
it of several nurserymen in the state.


This photograph shows an exaggerated example of the cluster type
of fruit: mainy individual fruits on one stem.


The tung oil's future development will be greatest in
those areas which are best adapted to it by reason of most
suitable sils and climatic conditions. It must be borne in
mind that this tree is more or less sub-tropical in require-
ments and that the region where it may be grown is limited.
It has withstood temperatures as low as 15 degrees Fahren-
heit without damage, but late spring frosts in the extreme
northern part of the planted area have been known to dam-
age the bloom. From reports of planters themselves it
seems that the tree will not succeed in the southern part
of the state.


The tree in large degree thrives in ratio to the fertility
of the soils on which it is planted. Usually plantings are
located on the higher soil types but, if adequate drainage is
provided, the lower lands are suitable for tung oil trees.
Many thrifty trees are now growing on such land. How-
ever, an absolute essential to thrifty growth on the lower
soils is a thorough system of drainage which not only
removes excess surface water but also lowers the water-
table to a point several feet below the soil surface. The
effects of inadequate drainage are not always apparent the
first or second year after planting, but later they appear
through a general lack of vigor, a condition that can be
overcome only by lowering the water-table.

In selecting tung oil land, avoid high, dry, coarse sand
hills. Likewise avoid low, undrained land. There is no
advantage in the former. In the latter there may be plenty
of fertility, but the high water level prevents the roots from
growing downward sufficiently deep.

Plantings have been made on several soil series with
satisfactory growth resulting in each case. These series
include Norfolk, Gainesville, Orangeburg, Greenville, Blan-
ton, Bladen and Leon. Soils with a slight acid reaction are
best suited to the tung oil. It apparently will not thrive in
a soil rich in phosphate and lime.

All soils are not suited to the culture of the tung oil tree
and prospective planters would do well to make rather
exhaustive soil tests and comparisons before investing their
motey or planting large acreages.



Seedling trees should be grown in the nursery from seed
selected from prolific parent trees. In the nursery select
the most vigorous trees, those which show a well developed
top and root system. The tung oil tree has been propagated
from seed for thousands of generations. Thus its heredi-
tary qualities are very deeply implanted and an unusually
high percentage of the young are true to the parents.
For this reason it is important to select the seed carefully
and later to select seedlings in the same manner. Then
follow up the trees during future years and when, after a
fair chance, one fails to measure up, eliminate it.

Tree records over a period of years kept at the Florida
Experiment Station (see Bulletin 221 of that station) at
Gainesville show that some trees are almost worthless inso-
far as yields is concerned, while others consistently bear
heavy crops. At that station the average yield from all its
plantings was greater from the cluster type trees, although
one or two individual trees of the single type were exception-
ally heavy producers.* These differences emphasize the
necessity of rigorous seed selection, whether the type be
single or cluster, in order that future plantings may have
the highest possible proportion of high-yielding trees.


Best results in growth and yield have been secured by
following a cultural system that includes five items of basic
importance. These are:

1. Thorough and complete clearing and preparation of
the land prior to planting.
2. Planting of only rigidly selected nursery stock; the
planting to be done during the tree's dormant period (De-
cember through February.)
3. Field cultivate shallow enough to leave the root system
undisturbed, and thorough and often enough to destroy
weed and grass growth which competes with the tree for
moisture and plant food. As the tree grows older and
attains size, less cultivation is needed. Mulching of young
trees on the higher soils with any coarse vegetable material
is advantageous, provided it can be done at little cost.


4. Fertilization adequate to maintain the tree in a vigor-
ous growing condition is essential. It is not sufficient that
the tree only set and mature its crop of fruit any given year;
a strong vegetative growth must appear along with each
fruit crop in order to insure a heavy yield the following sea-
son. It is only on this new shoot growth of this season that
fruit will be produced next season.

5. Maintenance and building up of soil organic content
and fertility by the growing of summer legumes in the row
middles are other requirements.

In China, its country or origin, the tung oil tree is grown
largely around the edges of very small farms and in places
not suited to the growing of regular crops. The average
farmer has from five to fifteen trees. He who has as many
as fifty is regarded as a large producer. Apparently no
effort is made to cultivate or fertilize or to improve the
stock by budding, grafting or seed selection. As a result
a crop of any size is accepted gratefully by the planter.

Under American practices of seed selection and tree ferti-
lization and culture, there is every reason to believe that the
production of a single Florida acre will be equivalent to
that of many Chinese acres.

Nursery stock is grown best on fertile, fairly moist but
not wet soil. The seed are planted from 3 to 4 inches deep
and from 8 to 12 inches apart in rows from 31 to 4 feet
apart. Middle-February planting gives the seedlings the
benefit of the full growing season for development and is
preferred to later planting dates. About 60 days are re-
quired for germination. Little success has followed the
planting of the seed directly in the field where the trees are
to grow. This is due in large degree to the failure to keep
the seedlings free of grass and weeds. Also the young
plants require much moisture, and on a wide acreage mois-
ture variation is great enough that some plants will suffer
and lag in their growth. Nursery stock from 4 to 6 feet in
height, which is of ample size for transplanting, may be
produced in one season. This nursery stock should be
carefully culled in transplanting; plant only the most prom-
ising seedlings.

On suitable soils and under recommended cultural prac-
tices the value of fertilization is not questioned. The indus-


try is yet too new to give final indications as to the best
fertilizer materials and practices. But in case of young
trees there is ample evidence to show that a lack of nitrogen
is the determining factor in limiting tree growth. At the
Florida Experiment Station a fertilizer analyzing 5 percent
ammonia, 8 percent phosphoric acid and 4 percent potash,
composed of nitrate of soda, cottonseed meal, sulphate of
ammonia, superphosphate and sulphate of potash, has given
best results.

It should be remembered that a soil must be correctly
prepared and contain a reasonable amount of organic ma-
terial, if best results are to be expected from commercial

Very satisfactory results have been secured in some com-
mercial plantings from the use of Peruvian (or bird) guano
supplemented with nitrate of potash. Applications are
generally made twice annually, the first early in the spring
and the last late in June. Quantities applied per year vary
from 1 to 7 or 8 pounds to the tree, the amount depending
on the size of the tree. B. F. Williamson of Gainesville says
he has found Peruvian guano most successful for tung oil
trees, though it should be supplemented by potash and phos-
phate when the trees come into bearing.

Since most soils suited to tung oil trees are deficient in
organic matter, it is generally recommended that a legumin-
ous cover crop be grown between the rows during the sum-
mer months. At present the crotalarias offer the greatest
return for the least outlay. The tonnage produced exceeds
that of other cover crops, the amount of seed required and
seed costs are low, and, if rightly handled, a succession of
volunteer crops for several seasons is possible. Cowpeas,
velvet beans and beggarweed are other admirable legumes,
but the first two of these have the objectionable habit of
climbing the trees. Mr. Williamson, who probably has made
a more extensive study of the tung oil than any private citi-
zen, is a strong advocate of the growing of cover crops. He
finds that cattle may be pastured on the cover crop without
injury to the trees and with advantage to the cattle.
In some cases inter-cropping is employed to some extent,
vegetables and corn being the principal crops grown in the
middles, so far as the writer has noticed. Such a cropping
system possibly is suitable, provided there is not too great


a drain on the soil fertility, and the cultivation given is com-
patible with tung oil tree needs. There is little doubt but
that the growing among the trees of such crops as corn,
sweet potatoes, cotton and vegetables will, if continued,
retard the growth of the trees more than where only le-
guminous cover crops are grown and returned to the soil.
It may prove poor economy to endeavor to secure a tempor-
ary gain from inter-dropping, in that it will likely result in
a loss in vigor and more or less permanent setback to the


Values of lands suited to tung oil trees vary considerably,
due to location and size of tracts involved. Clearing costs
also differ greatly and depend almost wholly on the type of
vegetation growing on the land. The number of trees
planted per acre (present planting range from 48 to 116)
will have a large bearing on nursery stock cost. In the
effort to arrive at expense of planting and maintenance it
must be born in mind that any figures are subject to wide
variations, because of differences in labor costs, methods
of handling, grass and weed growth, and other unforseen
factors, as well as acreage involved. Usually large acreages
can be maintained at less cost per acre than small plantings.

The first year's expense may be divided approximately
as follows:

Nursery Stock _-- $15.00 to $50.00 per acre
Clearing ---____ 8.00 to 40.00 per acre
Plowing, breaking ..-- 2.50 to 5.00 per acre
Planting -- 4.00 to 6.50 per acre
Cultivation ---5.00 to 10.00 per acre
Fertilizers and applying 4.00 to 6.00 per acre

No estimate is placed on the cost of the land used, inas-
much as land values vary greatly.

After the first year the fertilizer costs gradually increase,
but as the trees grow cultivation costs in turn gradually
decrease. Since about 10 pounds of fertilizer is the maxi-
mum quantity applied to mature trees, this expense will be
but the cost of 700 to 1,200 pounds per acre, plus the low


cost of application. From $25 to $30 per acre should cover
fertilizer and labor costs on a mature planting.


Under the crude methods followed in China, yields are
low in that country. From reports of those who have
investigated only from 20 to 30 fruits are yielded by trees
three or four years old. When the tree is six years old it
may produce 150 fruits, and at ten years of age the crop
may run as high as from 200 to 250 fruits per tree.

No acre plantings in this country have reached full ma-
turity. It is, therefore, impossible to give any data as to
yields on groves more than a few years old.

The original planting of 10 trees at the Florida Experi-
ment Station will furnish some indication of possible yields.
These trees, however, were planted but ten feet apart and
up to the time the yield records, as given below, were begun
they had little or no fertilization. Had they not been so
severely crowded, it is quite certain that they would have
produced much more abundantly. Over an eight-year period
(nine to sixteen years) these trees produced an annual
average yield per tree of 22 pounds and 5 ounces of hulled
seed which is equivalent to almost 1 gallon of oil. The trees
are not from selected stock and considerable variation is
apparent. For the period above mentionel five of the trees
produced 339 pounds of seed while the five trees of better
bearing capacity bore 1,443 pounds. This further demon-
strates the value and importance attached to careful seed
selection in growing nursery stock.

Records are available of one small commercial planting
of nearly 200 trees to the acre that produced in its fifth
year (sixth from seed) an average of 3,531 pounds of air-
dried whole fruits or the equivalent of 74 gallons of oil per
acre. B. F. Williamson reports instances where individual
trees have produced over 30 pounds of oil. He adds, "A
small acreage planted in 1925 showed an average yield in
1929 and 1930 of a little less than 700 pounds of oil per acre
per year. Other plantings have shown as high as 500
pounds per acre, these were 1924 and 1925 plantings and
the yield records were for 1929."


The reader may see for himself how impossible it is to
set forth in a publication of this kind definite figures relat-
ing to profits. It is even impossible to say with any degree
of certainty what the average planter should expect by way
of yield from his acres. But as regards profits, figures
compiled by the American Paint Journal show a range in
price of tung oil from January, 1919, through September,
1928, from 35 cents to 9 cents per pound. Naturally these
were the prices for the Chinese oil. American oil brings a
higher price, being of a much higher quality. But with
these import prices as a basis, with perhaps 141/ cents per
pound a high average, the prospective planter can probably
do his own figuring, inasmuch as he should know his own
situation better than any one else.


No fungus or insect has seriously attacked the tung oil
tree, either in America where it has been grown for 25
years in test plots or in China where it has been grown for
thousands of generations.
This cannot be said of any other commercial tree crop in
Florida. While two or three scale insects have been found
on it in isolated cases, there has been no instance wherein
commercial spraying has been required or even desirable.
In a few instances young nursery stock has been affected
by root-knot, but there is no record of this trouble's affect-
ing older trees. In order to keep nursery stock free of this
trouble, it is only necessary that the nursery be located on
newly cleared land, rather than on old.


The author is indebted to Harold Mowry of the Flori-
da Experiment Station and to B. F. Williamson of Gaines-
ville for much of the information contained in this publica-
tion and for much assistance in its preparation. Mr. Wil-
liamson gave a number of photographs which are reproduc-
ed herewith.


The following is from a bulletin, Number 133 of the
U. S. Department of Commerce, 1932:

Tung oil has attained prominence as an essential raw
material since the World War. Its distinctive character-
istics are keenly appreciated by progressive industries, and
as yet the product stands unequaled in its now well-estab-
lished fields of application.

The American market, outstanding in world trade in
this commodity, has keenly realized the uncertainty coin-
cident with complete dependence upon a distant foreign
source of supply. The lack of centralization of tung oil pro-
duction in China, long and hazardous transportation to
export centers, political and military unrest, varying intern-
al-tax levies, the tendency toward adulteration and other
conditions which have contributed to the speculative nature
of the trade have accentuated the desire of industrial con-
sumers to establish an independent source of supply in the
United States.


The possibilities of domestic tung-tree cultivation seem
first to have been visualized by Hon. L. S. Wilcox, United
States consul general at Hankow, China. He reported hav-
ing sent seeds in 1902 and 1903 and again in 1904 to some
person in the San Joaquin Valley of California, and that
plants from the first shipment had thrived. However, the
seeds had been forwarded through other persons, and later
attempts by the United States Department of Agriculture
to learn the name and address of this early experimenter
were unavailing.

Early in 1904 a small quantity of tung seed was sent
to Washington, D. C., by Consul General Wilcox, and these
seeds placed by the Department of Agriculture with several
experimenters in the warmer parts of the country. A few
plants were obtained and some lived for two or three years,
but all eventually died. In the meantime, Doctor Fairchild,
in charge of the Division of Foreign Plant Introduction,
Bureau of Plant Industry, had arranged with Mr. Wilcox
to purchase and forward a considerable quantity of seed


from which to raise young trees for extensive testing
throughout the South and on the Pacific coast.

The larger shipment of seed was received by the Bureau
of Plant Industry in 1905 and was planted principally at
the Plant Introduction Garden of the Division of Foreign
Plant Introduction at Chico, Calif. A large number of seed-
ling trees resulted. When the trees were 1 year old they
were shipped to State experiment stations, city parks, and
cemeteries, and to private individuals throughout the mild-
er parts of the country for test plantings. Fairly large
numbers of trees were set out in Alabama, at Fairhope,
Robertsdale, and Batesville; in California, at Riverside,
Pasadena, and Los Angeles; in Florida, at Tallahassee, Mc-
Intosh, Lutz, St. Petersburg, and Gainesville; in Georgia,
at Augusta, Cairo, Thomasville, Lagrange, and Donaldson-
ville; in Louisiana, at Pineville, Abbeville, Alexandria, and
Bolivar; in Mississippi, at Biloxi, Landon, and Lucedale; in
South Carolina, at Bennetsville; and in Texas, near Hous-
ton; while single trees were planted in a number of other


These early plantings indicated that Aleurites fordi
could probably be grown successfully only in the Southern
States, where its fruit buds would not be injured by early
frosts, while the montana species would be suitable primari-
ly in more subtropical regions. The greatest interest was
initially manifested in Florida, and, largely as a result of
plantings and research effort in that State, the tung tree
became better known in the South, and cultivation experi-
ments became widespread throughout the entire Gulf coast-
al region.

It seems strange to relate that the life of this promis-
ing new industry was really begun in a Florida cemetery.
Five of the firsu seedlings cultivated by Doctor Fairchild
at Chico, Calif., were dispatched to the superintendent of
a cemetery at Tallahassee, Fla., and were planted but given
little attention. In the autumn of 1906 William H. Raynes,
of that city, became interested in the neglected plants and
was given permission to transplant them. Only one of the
five trees survived, but that tree still standing, serves as
a monument to early pioneering efforts to establish the cul-
ture of the tung tree in the United States.


Stimulated by the enthusiasm of Mr. Raynes and assist-
ed by a gift of 100 seedlings from the original tree, a neigh-
bor, Dr. Tennent Ronalds, became interested and planted
a 4-acre grove near Tallahassee in 1912. This planting,
later enlarged to 40-acres, became the first bearing grove of
tung trees in America. The Raynes tree at Tallahassee
served not only as an important early source of seed for
subsequent plantings, but in 1913 furnished a sufficient
crop to make possible the first trial expression of tung oil
in the United States. This experiment, conducted by a
representative of the Paint Manufacturers Association of
the United States, yielded 2.2 gallons of oil from the bushel
of whole fruits submitted.

The results of preliminary experiments in the introduc-
tion and adaptation of the tung tree in the United States
were presented to the largest consuming factors in the
tung-oil trade by Doctor Fairchild in addresses before the
Paint Manufacturers Association of the United States and
the National Varnish Manufacturers Association, in the fall
of 1912, to invite their friendly interest and cooperation in
domestic tung-oil cultivation projects. These two groups
were favorably impressed with the prospect of a domestic
industry, because of the dependence of member manufact-
urers on China for supplies of this important varnish oil.
Although consumption of tung oil was constantly increasing,
the uncertainty of shipments, resultant speculation, and
wide price fluctuations, as well as the variance in quality
of the imported oil, caused considerable uneasiness among

Therefore, during the fall seasons of 1912 and the four
years following, Henry A. Gardner, representing the two
associations mentioned, visited the southern Gulf States to
investigate the commercial possibilities of tung-tree culti-
vation in the South. A favorable report on this survey,
completed in 1921, resulted in more active efforts on the
part of these associations to stimulate plantings in the Unit-
ed States.

In 1923 the American Tung Oil Corporation was form-
ed as a subsidiary of the American Paint & Varnish Asso-
ciation, primarily to demonstrate the possibilities of pro-
ducing tung oil in the United State. This company, fin-
anced exclusively by leading domesticc paint and varnish
manufacturers, was designed and operated as a nonprofit-
making venture, to encourage the growth of tung trees


on a commercial scale in this country, and thereby ultimate-
ly to develop a domestic supply of oil. Assistance to
prospective planters was to be rendered through the devel-
opment and dissemination of accurate information relative
to proper planting practice, based upon experience of the
corporation in experimental planting. About 200 acres
were initially acquired at Gainesville, Fla., upon which tung
trees were planted, under widely varying conditions, for
observation. The establishment of this experimental grove
jointly by.individuals representative of the largest market
outlet for the oil marked the beginning of a period of real
progress in tung-tree planting in the United States.

Tung oil expressed from seed yields of domestic plant-
ings examined by Doctor Gardner and the research staff
of the association even in early experiments was reported
to be of better color and quality than oil procured from
China. These and many subsequent studies both by official
and by private agencies pointed to a future market for do-
mestic tung oil, predicted naturally upon the development
and success of extensive commercial plantings and the
economical harvesting of the nuts and expression of the
oil, and its sale at competitive prices.


The planting of tung trees has been suggested as a
solution of many of the difficult agricultural problems of
the South. The outstanding position of cotton in the eco-
nomic life of many of the Southern States has resulted in
marked fluctuations in individual and general business pros-
perity following closely trends in the Cotton market. It
is contended that the addition of a new industrial crop will
assist in diversifying agricultural activity and thus may
bring a more balanced prosperity to that region.

Timber exploitations in the South far exceeds replace-
ment by afforestation and in certain States is rapidly ex-
hausting this important natural resource. The large and
increasing acreage of cut-over timberland represents, at
present, a considerable economic loss to the South. There-
fore the problem of a profitable utilization of these waste
lands has been of material concern to lumber companies
and owners of such property in the Gulf coastal region.
Tung nuts have been visualized as a potential crop for some
such areas, and lumber firms have played an important
part in the encouragement and development of tung-tree


plantings in Mississippi, Louisiana, and Texas. If the tung
tree satisfactorily solves this problem, benefits will accrue
not only to property owners, workers, and all classes deriv-
ing income or sustenance from the land, but to county and
State treasuries as well, in the form of increased tax re-

Extensive planting of tung trees may lead to the devel-
opment of a substantial milling industry, a movement in
keeping with the trend toward industrilization now quite
evident in the Southern States. Since tung oil, turpentine,
and rosin are essential raw materials in paint and varnish
manufacture, certain leaders in the paint industry, as well
as tung-tree planters, have visualized the commercial pro-
duction of tung oil in conjunction with the already well-
developed naval-stores industry of the South as an incen-
tive to the extension of paint and varnish manufacture ir
that region.

Forestry authorities in various States of 'the South
have recommended the growth of this tree in hilly or rolling
areas, where its long tap roots would serve as a protection
against excessive erosion and resultant exhaustion of the
soil. Such planting may assist farmers in the more econ-
omic use of their uncultivated land, since tung trees grow
satisfactorily on hillsides and on irregular plots of ground
which may be difficult to utilize for general farming. In
some localities a few plantings are being made along rail-
road tracks, highways, and edges of fields, so that the trees
in addition to yieldng nut crops, may be used instead of
posts for stringing wire fencing. The tung tree is beauti-
ful in bloom and may add greatly to the scenic inducements
of the South to attract tourists and vacationists.
Tung-tree groves may be worthy of consideration as
a supplementary crop for small landowners. The location
of many small groves in the same vicinity, making possible
cooperative cultivation and harvesting efforts with proper
equipment, should result in more profitable returns to indi-
vidual planters. It is generally conceded, however, that the
success of tung-tree plantings as a business venture will be
evidenced principally in large-scale commercial develop-
ments in the areas best adapted to their growth.


In considering cultivation of the tung tree from an econ-
omic standpoint as the source of an oilseed crop, it may be


interesting to visualize the possible areas in which Aleurites
fordi may be successfully grown, guided by our present
knowledge of climatic and soil requirements of the tree.
Experimental plantings throughout the United States
disclose that the areas for successful commercial growing
of tung trees will probably be restricted to a rather narrow
strip of land, in most places probably 100 miles wide, or
less, ebracing the southern portions of the State of Ala-
bama, Mississippi, and Louisiana, the north third or half
of the Peninsula of Florida, the eastern and northern Gulf
counties of Texas, and the southern and southeastern sec-
tions of Georgia.
Mature tung trees have been known to withstand severe
temporary droughts without serious inquiry, but generally
a minimum annual rainfall of 30 inches is considered es-
sential to satisfactory growth, while best results are ap-
parently obtained in regions where the rainfall averages
over 40 inches each year. The western limit of successful
planting is considered at about 98 longitude, in Texas,
since experiments made in California and other regions
west of that line have shown that the rainfall there was in-
sufficient or too irregularly distributed throughout the year
to furnish proper nourishment to the trees.
The southern and northern limits of tung-tree culture
will be determined principally by temperature considera-
tions. The tree is deciduous and therefore thrives best where
there is sufficient cool weather to allow for a dormant
period, but only in regions where early or late frosts will
not injure the fruit-bud growth. Young trees not thorough-
ly nourishment or not completely dormant often succumb to
a sudden drop in temperature below 200 F. On the other
hand, older trees have been known to withstand a tempera-
ture below 100. Therefore in Texas, Louisiana, Mississippi,
Alabama, and Georgia, the northern half has proved to be
unsuitable, owing to frequent and rather extended frost
occurence. Records indicate that a few trees have lived
for several years and borne fruit in various districts of
Arkansas, South Carolina, and North Carolina, but usually
have failed to maintain a uniformly healthy growth or to
yield an appreciable nut crop, and all have later died from

Soil and drainage requirements of the tung tree will
largely determine the regions within the potential growing


area which will successfully foster commercial plantings.

Although reports from China have suggested that both
Aleurites fordi and Aleurites montana will enjoy fair growth
in practically any type of soil, much better results have
been obtained in the United States through proper soil selec-
tion, and adequate consideration should be given to this
factor in choosing areas for commercial planting. In China
the tung tree ordinarily has a productive life span of 15 to
20 years in the poor hillside soils in which it is commonly
grown, but in more suitable soils it may show satisfactory
yields for 30 years and even longer.

Aleurites fordi has apparently very marked soil prefer-
ences, based upon the nutriment demands of the tree. Its
root structure and general rapid growth demonstrate that
it is a heavy consumer of nitrogen and water. Plant foods
should necessarily be available in soluble form so that the
tree may readily take them from the soil. This fact illus-
trates the definite relation of rainfall to soil in tung-tree
culture to allow full advantage of nutriment present in the
soil and to insure constant and vigorous feeding of the
tree. Rather heavy and fairly evenly distributed annual
precipitation, particularly important during the periods of
growing and fruiting activity in the ,pring, summer, and
early fall, is therefore considered essential to prolific growth
of the tung tree.

Plantings in the United States have been made on a
variety of soil, but planting experience has not yet been
sufficiently wide-spread to indicate definitely the most suit-
able soil types upon which, to grow the tung tree. Satisfac-
tory growth has been reported on well-drained soils of the
Orangeburg, Greenville, Norfolk, Ruston, Tifton, Eusque-
hanna, Fellowship, Hernando, and Gainesville series. The
character of the soil may determine the extent and charac-
ter of fertilizer required.

Soil uniformity over large areas is very desirable in
commercial planting, since this condition contributes to
the rather even development of the trees, tends to equalize
drainage over the region, and indirectly reduces the cost of
oilseed production by allowing standard practices of plant-
ing, cultivation, and fertilization.

It has been very definitely established in American
experience that an acid soil should be selected. Just how


strongly acid the soil can safely be has not been proved, but
it is considered desirable to plant tung trees in soils having
a pH from 5 to 6.8. (The term pH has been used in recent
scientific agricultural practice as a measure of soil reaction.
Neutral soils have been assigned a pH of 7, figures above
that standard indicating an excess of alkali, and lower fig-
ures denoting an acid predominance in the soil.) Neutral
soils are not considered particularly adapted and require
considerable attention, while alkaline soils have proved in-
jurious to the growth of the tree. Planting experiments in
the United States have shown that lime or any other source
of alkalinity is dertimental to the development of the tree,
even when present in the lower subsoil.

Excess lime content, for example, has resulted in a
stunted and unhealthy growth of the trees and a chlorotic
condition of the leaves. Also, the bronzing of the leaves and
the gradual death of the whole tree has been caused by ex-
cess tricalcium phosphate in the soil.

All authorities agree that good drainage is absolutely
essential to the best growth of the tung tree. Soils should
be of a character to allow satisfactory passage of rainfall,
and it is even requisite that the lower subsoils permit easy
seepage of water to lower levels. Sufficient porosity to al-
low air penetration is considered desirable as an aid both
to proper soil drainage and to feeding of the roots.

From the foregoing presentation of essential soil and
drainage factors, it appears likely that the poor drainage
characteritsic of certain sections of Louisiana and other
Gulf States would naturally eliminate a considerable acreage
in that area from consideration, while alkaline soil and pre-
valence or spotty occurrence of phosphates or lime would
restrict development in some counties of Florida, and to a
degree elsewhere in the south.


Progress in adaptability of the tung tree to widespread
areas in the South may be visualized from Figure 18, which
shows the regions in which favorable growth or commercial
planting has been achieved. For the purposes of this study
total tung-tree acreage in a county in excess of 500 acres
has been considered commercial planting. Favorable growth
indications are based upon rather conclusive evidence of
successful experimental or small-scale planting. These two


designations, however, dc not necessarily imply uniform
promise throughout the counties for which they were re-
ported. Absence of markings does not indicate lack of possi-
bilities, but merely the absence of data or of actual plant-
ings upon which to comment.


Although definite current reports are not available
from all plantings, an attempt has been made to ascertain
the acreage in groves of tung trees in the United States in
the spring of 1932 to illustrate statistically the progress
and present development of this undertaking within the
present growing area. Carefully checked estimates based
on available data indicate that the total acreage in tung
trees in the United States on April 1, 1932, was between
28,750 and 31,000 asres, distributed as follows:


State Minimum Maximumn State Minimum .Iiximum
Florida ..-... 14,000 1 5 10 Alabama 600 750
Mississippi 10,5011 11,000 Texas I 400 I 500
Georgia .... I 1,750 : 2,01" .
Louisiana 1,50 1,750 Total 28,750 I 31,000
A minimum and maximum figure is selected for each State to allow for
numerous individual trees and small groves known to exist but for which
definite acreage figures are not available.

A detailed description of planting by States is present-
ed to show the character, location, maturity, and compara-
tive progress of groves in each of the planted areas.


Until very recent years tung-tree planting in the Unit-
ed States was confined principally to Florida. Its initial
development there reflects the great interest in new crop
possibilities which has been manifested in Florida during
the past decade. During the early period of introduction of
Aleurites fordi, other Gulf States were concerned mainly
with standard money crops, such as cotton, cane sugar,
rice, peanuts, fruit, and general truck produce, from which
good returns were being received. Also, available timber
resources had not been sufficiently exhausted at that time
to attract serious attention to the problem of the economic
utilization of cut-over lands.


Two distinct periods of development are noted in the
progress of tung-tree planting in Florida. The first, cover-
ing the years 1907 to 1923, was characterized by adapt-
ation and cultural experiments conducted on a small scale,
while the second includes the subsequent years, during
which substantial progress has been made in propagation
of the tree.

Early experimental plantings, which were quite suc-
cessful in northern and central Florida, tended to encour-
age further development of plantings throughout the State.
Climatic conditions were found to be favorable to the healthy
development of the tree, infrequent frosts and ample rain-
fall being cited as definite advantages of the Florida areas.
The year 1924 witnessed the beginning of commercial-grove
development, a movement which has gained increasing
momentum in Florida since that time. The following tabu-
lation indicates statistically the progress of plantings in
that State.


Total Annual Total Annual
Acreage increase Acreage increase
Year (esti- in acre- Year (esti- in acre-
mated) age mated) age

1923 --- 140 1928 4,000 1,000
1924 300 160 1929 .... | 5,500 I 1,500
1925 1,020 720 1930 [ 7,750 2,250
1926 [..... 2,000 980 1931 .. 11,500 I 3,750
1927 --- -- I 3,000 1,000 1932 (as of Apr. 1) I 14,500 [ 3,000
___ _i ____ ________

Estimated on acreage planted the number of bearing
trees increased from 3,300 in 1924 to over 400,000 in 1931.
During 1932 nearly 150,000 more trees will reach initial
bearing age.

Although plantings of tung trees were first establish-
ed in Leon County, the center of activity shifted early in
1923 to the Gainesville region, in Alachua County, influenc-
ed to some extent by the important experimental plantings
being carried on in that vicinity by the American Tung oil
Corporation and by the State agricultural experiment sta-
tion. Commercial-grove development has radiated to neigh-
boring counties since that time, the major plantings now
being reported in Alachua, Clay, Putnam, Marion, Levy, and
Lake Counties, as well as in the original Leon area sur-
rounding Tallahassee. Extension of established groves in


north and central Florida was most marked during 1930
and 1931, and several new projects of outstanding import-
ance in that region were initiated during this period. Ex-
tensive nursery planting and experimental work are being
carried on farther south in Polk and Hillsborough Counties.
Very recently large groves have been set out in Suwannee
County, in north Florida, and in Okaloosa County, in the
extreme Western part of the State.

Individual plantings are numerous and show consider-
able variance in size. About 10 large companies are develop-
ing tung-tree acreage in Florida, their groves ranging from
750 to over 2,000 acres each. A large number of plantings
of 10 to 200 acres are reported, many of which are engaged
principally in raising nursery stock for sale to the large
planters. Experimental growth of the tree is still being
undertaken, and many sections of the State have reported
favorable results which seem to justify large-scale activity.

The outstanding contributions of the Florida develop-
ments have been in the field of planting and technical re-
search. Active and exhaustive adaptability trials to discover
the climate and soil conditions which would foster the best
development of the trees have been conducted continuously
since 1912 by the experiment station at Gainesville and
since 1923 by the American Tung Oil Corporation in co-
operation with many private investigators and planters
who have reported periodically to those research agencies.
Activity in horticultural research in connection with tung-
tree plantings has been most marked during the past three
years, a period which has witnessed the greatest progress
of this important oilseed industry in the United States.
Harold Mowry, of the University of Florida, has been one
of the outstanding scientists engaged in this work.

Careful studies of planting practice, soil reactions,
fruit-bud development, suitable cover crops, fertilizer re-
quirements, relative yields, and many other pertinent sub-
jects have been made, and conclusions have been reached
which have served to enlighten prospective planters and
encourage the extension of commercial groves within the
State. Chamber of commerce officials and county and State
groups have been particularly active in stimulating inter-
est in the possibilities of the tung tree in the Florida area.
During the spring of 1932 the Gainesville Chamber of Com-
merce directly aided in fostering development by arrang-
ing with large nursery owners for the distribution of nearly




100,000 yearling trees to interest Florida farmers in lo-
cations certified by county agents to be suitable for tung-
tree plantings.


Gainesville, Fla.

In the paint and varnish industry there are several
hundred items into which tung oil enters as a part of the
composition. Among these are included the following:
Anti-fouling compounds, baking enamels, body oils,
bronzing liquids, cement paints, chill-back oils, core oils,
drying salts, ester gums, elastic products, fish-oil com-
pounds, flake finishes, flat coating, glycerine compound,
gold sizes, impregnating compounds, insulating compounds,
iron fillers, japans, lacquers, linoleates, linoleum oils, liquid
driers, liquid enamels, oleated thinners, paint binders, paint
hardeners, paint liquids, pastes for paints, paste thinners,
plastics, polishing oils, prepared oils, prepared rosins, pre-
pared resins, resinates, resin toughener, rubbing oils, rust-
proof compounds, sealing compounds, sebate compounds,
shellac compounds, sizings, stearated compounds, thinning
liquids, tinters, tungates, turpentine substitutes, varnish
removers, vulcanizing compounds, waterproofing com-
pounds, water solutions, wax oils, wax oil soaps, and several
hundred varieties of paints and varnishes.

Since we first commenced to grow Tung Oil I have work-
ed with an idea of manufacturing the Tung Oil into finished
products and we have instances where paint and varnish
has been applied in some cases as long as ten years. In
many instances the Tung Oil paints and varnishes have
shown twice the life of the high grade linseed oil varnishes
under our climatic conditions. Florida is one of the hard-
est states in the Union on paints and varnishes. If when
we produce the oil we manufacture and use it close to the
source of production it will affect a dual economy, establish
a market which will insure the grower a better price for his
oil and will retain in the community the raw material profit
as well as the manufactured profit.


A few years ago a serious disease, called "bronzing,'
began to menace the trees. Within the past two years ef-
fective control measures have been discovered. The treat-
ment recommended by the Experiment Station starts the
trees into normal growth and speciments in bad condition
have shown astounding recoveries.


Walton --
Leon ----.
Lake --
Several other
of some

counties make a total

Estimated by the County Agents.


Some people have questioned the practibility of produc-
ing tung oil in America in competition with cheap Chinese
labor. Julean Arnold, the American commercial represen-
tative at Pieping, says that Chinese can be employed at 15
cents per day, but one of the American presses will do the
work of 90 to 100 Chinese. Transportation in China, he
states, is on human backs and costs five to seven times as
much as transportation in this country, even with our ex-
pensive labor and high freight rates. Manufacturing in
America will be done with machinery from the time the
nuts are delivered to the press. Cultivation in this country
is also done by machinery. Three small tractors will culti-
vate 100 acres in a single day.



Per Lb. BBLS, New York
American Paint Journal, Nov. 1, 1933


Jan. ---- $.21%
Feb. --- --- .19L/2
Mar. --- .18%
SApril .17
SMay .-- 15
June ---- .14
p July .15
SAug. .- 15
5 Sept. -----.------ 15/
9 Oct. .--- 161/
< Nov. --- .16
R D c ------ .16
z H
r Jan. $-16
H Feb. 142
P4 Mai. ------
< April .----143/4
P May .14%
SJune ----- .141/2
IJuly .----- .14%
Aug. .-- 1414
Sept. .--- 16
Oct. ------ .151/
M Nov. .---- 1514
: Dec. -----------.- 1441/

;.194 | $.16
.17% .14%
.17 .14
.14%3 .13V1/
.14 .13
.121/2 .141/
.111/2 .14
.14 .131/2
.141/% .131/2
.15 .131/2
.15%1/ .13/
.151/2 .13%2

$.14% $.12'/2
.141/4 .12%
.14 1 .12
.14/% 1 11
.141/2 11

.14%4 .101/4
.14 .09%1/
.14 i .091
.141/2 .09
.15 .08%
.141/ .07
.131/ .07

$.143/% $.1
.13 .1
.13 .1
.13 .1
.12% .
.12/2 .
.13 | .
.13% /

3V2 $.13 $.151/ $.131/ $.18
31/2 .121/ .181/ .17 .17%
12% .121/4 .27 .22 .15
L22 .111/s .35 .30 ,16
12 .11% .29 .191/2 .15
15/2 .15 .21 .20 .15/2
164/ 1 .15 .201 17 .1512
L8 .17 .18 .17 .17
19 .17/ .18 .16 .15
17 .16 .16 .15 .15/2
16 15 .15/ .15'4 .15
143, 14 1 .151/2 .14%/ .14%

$.11% | ?07%h
.111/% .07
.11 1 .07
.110 .07%

.091/ .07%
.09 .071/2
.09 .06%
.08% .07%
.07% 1 .07%2
.07 .07%
.07 .071/

. H

$.07 $.071/8s
.06% .07
.062 i .07%
.07 .063/
.061/% .061/4
.06%1/ .06%1/
.07 .06%
.061/4 .063/4
.06% .06%
.07q/s .06
.071% .06
.07 .06

$.06%1 $.05%
.06% .05%/
.06%1/ .06
.06 .051%
.05% .061/
.06 .07/4
.06 .096
.05% .082
.05/4 .078

.15 1
.14 a
.14 V/f!

.051 %
.07 '2




Looking at this matter from every standpoint, it would
appear that here is an industry where over-production is
a long way off, where demand exceeds supply, and where
the product is an essential in an established industry al-
ready developed and rapidly increasing. Assuming that in
the near future the American production of oil will cover
the regular increase in the American demand, then as the
European demand increases it is likely that China may meet
it so long as prices remain high. At the same time it is
certain that there is a limit to the production of tung oil
in China, and there is no indication at present of increased
cultivation in China taking care of the increased demand.
Actually, the trees are not cultivated systematically in
China, for they are hardy, at least when past the seedling
stage, and are commonly found on hillsides or in rocky situ-
ations and on the poorest of soils, unsuitable for ordinary
food crop cultivation.

It has been said that the consumption of tung oil in
China greatly exceeds and may double the total export, but
this reservoir of oil is certainly not available except at good
prices. It is evident that an increasing world demand must
encroach more and more on the stocks of material norm-
ally reserved for domestic use in China with a consequent
upward tendency in price. The disturbed state of the coun-
try can only accelerate this effect since one would expect
supplies to shrink rather than expand. Under the best con-
ditions the difficulties in collecting the nuts, for the tree
is gregarious in habit, expressing the oil by native methods,
and transporting the oil from the interior to the ports, are
many; years of civil war cannot have made these difficulties
any easier.

In spite of the labor and the large percentage of waste
involved in the operations, tung oil is regarded as a most
profitable crop by the Chinese. In this very fact lies the
strongest argument for presuming that scientific cultiva-
tion of the trees in plantations, with adequate machinery
for crushing and collecting the oil, is bound to succeed. The
systematic cultivation of the tung oil tree may well follow,
though on a smaller scale perhaps, the example of rubber.
Today it is a fact that rubber grown in its true home, the
Amazon basin, although there are countless trees available,
cannot be produced at the cost of plantation rubber, be-
cause the method of ordered, scientific cultivation of the
tree and harvesting the product is more effective than the
casual collection of the jungle product.


Such information as is available on the subject of crush-
ing tung oil seed in China indicates that the husks are first
removed by parching the fruits over a fire in iron pans
(18 in. diam.), or by allowing the husks to ferment away
from the seed, the fruits being piled in heaps for this pur-
pose. The seeds are then ground to a meal in stone mor-
tars (about 3 ft. in diam.), using man or bullock power.
The meal is then heated, mostly by steam, and placed in
wedge presses. The oil is finally strained through silk or
grass cloth. Sun curing the kernels before crushing is said
to produce a light-colored oil, while extreme heat or ex-
cessive fermentation under bad conditions yields a dark
colored oil. It is also usual to press twice, the once pressed
meal being re-heated more strongly than before. The first
cold-pressed oil is said to be mostly exported, and to dry
more rapidly than the second hot-pressed oil which is re-
tained for domestic consumption.

Attempts have been made to establish a tung oil press-
ing centre on European lines at Shanghai, but there has
always been difficulty in obtaining a full supply of seed.
The Chinese much prefer to crush the seed locally, trans-
porting only oil.

In America the fruit is allowed to fall upon the ground
and may be picked up at any time convenient to the labor
on the groves. They are then delivered in bags to the oil
mill. Power conveyers eliminate all human labor at the mill.
The fruit is delivered direct to decorticators which cut away
the hulls and transfer the seeds to an electrified fanning
machine which shakes them at high speed and eradicates
foreign material. Conveyors then carry the cleaned, hulled
seed in a steady stream to cracking machinery which ham-
mers them just hard enough to break the shells and pre-
pare the meats for oil expression. The meats are then de-
livered to powerful presses which squeeze out all the oil
that can be expressed.

The first laboratory pressings of American grown seed
were made in 1924, using an Anderson expeller and an
ordinary hydraulic press. It was found that an extremely
light-colored oil could be produced if the seed had been
properly dried, either by the sun or by exposing the seed
upon flat trays in heated rooms. On the other hand, if


seed still contained moisture, a very dark-colored oil re-
sulted. This was found to be due to the high moisture con-
tent of the shells of the seed which resulted in slimy matter
being carried into the oil during pressing. It was also
found that the heating of seed containing moisture con-
tributed to the development of color and to the develop-
ment of acidity through hydrolysis.

Attention is also drawn to the very low acid value of
oil produced from American seed. It is believed that the high
acidity of foreign oil is due to improper storage of the
seed. The development of enzyme action during storage
of the seed in moist places, or by hydrolyzing effect of
water in stored oil before shipment and the setting free
of fatty acids would be contributing factors in this direc-
tion. Everything points to the need for effective drying
of the seed before storage and before pressing.

Early in 1928 large scale experiments were undertaken
in hulling, separating and expressing oil from the 1927
crop of fruit. Some 14 tons of fruit were available for these
tests. Decortication was successfully accomplished in a
24 in. disc. huller and a separator. In this operation the
whole fruit was delivered to the disc huller which decorti-
cated and discharged the cut seed direct to the shakers of
the separator. In the huller the position of the discs may
be varied with a tempering screw in order to control the
amount of pellicle to be left on the seed. The separator
does its work through both mechanical and pneumatic ac-
tion. The decorticated seeds from the huller are sifted
onto shaking trays, the loose kernels falling immediately to
the lower tray. The coarse bulk, consisting of outer hulls,
then passes over the upper tray until the mass comes with-
in range of the aspiration chamber where it is lifted by
suction, passed through the fan, and delivered to the cy-
clone collector which may be placed in any convenient loca-
tion. The cyclone collector is part of the apparatus. Be-
fore being discharged from the end of the lower tray, all of
the separated seed is purified by air suction which removes
small particles of hull, etc., which may have passed through
the perforations of the upper tray.

The rate of working was an intake of approximately
3,000 pounds of fruit per hour. The return was 36 per cent
of shelled seed ready for oil-crushing purposes, substan-
tially free frcm the hard pellicle or skin (which contains
no oil); only a sufficient quantity of skin being allowed to


go through with the seed to give a satisfactory "bond" for
proper expelling results.

The Anderson expeller equipment used for the test was
the standard type consuming 15 h. p., costing in all about
$5,000.00. The machine has yielded approximately 50 gal-
lons of oil per hour, with an over-all estimated expense for
crushing of $8.00 per ton of fruit.

In these tests 28,587 pounds of fruit were experimented
with and only 91/2 hours were required for complete hull-
ing of this quantity. The hulling was extremely efficient,
the outer hull being removed and much of the inner hard
pellicle, so that the seed to be crushed was concentrated
down to about 36 per cent of the total fruit. The majority
of this product for crushing was in the form of white meats
without the outer pellicle, and contained over 48 per cent
of oil. As stated heretofore, the seed with the hard pellicle
usually contains only 35 per cent of oil. After crushing
the press cake contained only a little over 5 per cent of oil.
It is evident that the press cake could be produced with
an oil content not exceeding 5 per cent, and special attention
has been directed to its value as a fertilizer on account of
its nitrogen, phosphoric acid and potash contents. It is now
being used experimentally as a fertilizer on the groves of
the American Tung Oil Corporation.

As an indication of the possible fertilizer value of tung
oil press cake versus guano, it may be stated that the aver-
age analysis of the guano purchased for the groves at $48.00
per ton during the years of 1926 and 1927 showed from 4
to 10 per cent of phosphoric acid, from 5 to 6 per cent of
nitrogen equivalent to ammonia, 1.2 to 1.6 per cent of pot-
ash, and from 8 to 12 per cent of moisture, whereas the
tung oil press cake showed from 1.7 to 2.7 per cent phos-
phoric acid from 4 to 6 per cent of nitrogen equivalent to
ammonia, about 1.2 per cent potash, and from 5 to 6 per
cent moisture.

The potash and phosphoric acid contents of tung oil cake
as reported above have been substantially confirmed on
Chinese fruit examined in England. It is generally con-
sidered in America that the fertilizer value of the cake
will offset the cost of crushing. The outer husks removed
from the seed are practically useless even as fertilizer,
containing only about 0.6 per cent of available ammonia,
but their return to the soil would add appreciably to the


humus content, and this would be an important matter on
sandy soil. The outer husks should have a value of $4.50
to $6.00 per ton.


A most important feature in the study of tung oil is the
fact that it has often been liable to heavy adulteration.
Adulteration with soya bean oil, rapeseed oil, tea seed oil,
perilla oil, and sesame oil is still occasionally practiced, ac-
cording to some authorities. One of the most interesting
points of attention about the American production is the
prospect of securing a really pure oil extracted under clean
and proper conditions.

The values in the table (page 38 have been reported for
various samples of oil obtained by laboratory expression
from small lots of American grown seed as early as 1924.
The high gravity, high refractive index, low acidity, low
heat test, and excellent color are noteworthy.

During 1928 the American Tung Oil Corporation distri-
buted a considerable weight of American grown tung oil to
eighty varnish manufacturers for large-scale varnish-mak-
ing tests. Practically every one of these manufacturers
reported the American oil to be superior to imported oil.
It is quite clear from the reports of the results obtained
that American oil is entirely satisfactory and generally
superior to imported oil. To quote examples, one maker
reported a slight improvement in color of his finished varn-
ish when made with American grown oil; another reported
that American oil gave a faster bodying action in the kettle,
producing a paler, clearer varnish with a somewhat faster
and harder drying film and with better hot water resist-
ance; another reported that the American oil made tougher
and more elastic varnishes with better water resistance, etc.
There seems no doubt about the fact that American grown
tung oil will be acceptable to the industry. At no time ha.
a sample of oil been found to give abnormal properties.


Cold Cold
pressed pressed
Florida Florida Alabama Alabama
No. 1 No. 2 No. 3 No. 5

Appearance and color All 1palel and clear

Spec. gravity at 15.5 C.1 0.9411 0.944 1 0.942 0.941
Acid number 0.5 1.5 1.2 1 1.36
Saponification number 1193.8 1194.4 191.6 1191.5
Refractive index 1.5191 1.5175| 1.5187| 1.5188
Iodine number 166.0 161.0 1166.8 |166.1
A. T. M. heat test 10/ 9/8 10 1 11


Land suitable for the cultivation of tung oil has been
offered in various regions in Florida, Louisiana and Mis-
sissippi at prices ranging from $5.00 to $10.00 an acre when
in the uncleared state. Some land at slightly higher fig-
ures has been offered when very close to prominent towns
and situated directly upon hard surfaced highways. It
should be stated, however, that the location of the land is
an important consideration, and that a slightly greater out-
lay for good land will in the long run prove much more
economical than the purchase of low grade lands because
of a supposed initial saving. The original 200-acre Para-
dise grove of the American Tung Oil Corporation, which
lies adjacent to a hard paved road, within two or three
miles of Gainesville, was purchased at $20.00 an acre. The
cost of clearing the pine trees from the acreage probably
varied from $40.00 to $60.00 an acre. Difficulty in securing
good drainage added greatly to the cost of preparing some
areas of this land for groves.

Throughout the northern part of the State of Florida
there are thousands of acres of suitable land which have
been cleared and heretofore planted with other crops. Many
of these lands have been idle for years. They could readily
be put in condition for the growing of tung oil. Lands of
this character have apparently been sold at from $20.00 to
$60.00 an acre. It is claimed by some investigators that
new land which is covered with pine trees could hardly be
purchased and cleared for the planting of tung oil at the
above figures.



The cost of clearing land will depend upon the kind of
trees to be removed, the density of the stand, the possi-
bility for sale of timber or fire wood, and the quality of
the supervision. For example, scrub oak land can be clear-
ed at a cost of $12.00 an acre and may run as high as
$35.00 dollars per arce. What might be termed grubbing,
that is taking out small groups of trees and brush from
land that is called cleared and has been farmed, will usually
average $5.00 per acre. A dense stand of live oak, gum
and pine may run as high as $75.00 per acre. The average
stand of mixed hardwood and pine will average $55.00 per
acre. The average cost of clearing 560 acres on the prop-
erty of the Alachua Tung Oil Co., according to H. I. Hask-
ins, the Manager of Operations for Benj. Moore & Co., was
$52.00 per acre. The lowest cost was $20.00 per acre and
the highest cost was $65.00 per acre. The experience of the
Alachua Tung Oil Co. was that the stump puller was not
a success. The cheapest method found was to cut the tree
roots eighteen inches below the ground, allowing the tree
to fall.


During the first three years of the tree's life in the
groves, there will be some mortality. The number of trees
lost will depend upon climatic conditions, care at time of
planting, and supervision of the grove. The figures ran
from 3 per cent to 22 per cent on one Florida grove, and
a fair average might be 8 per cent. The mortality after
the third year should drop to a very low figure.


The selling price of tung oil seedlings of the multiple
cluster type has usually ranged from 15 to 40 cents each,
according to the quantity sold and condition of the seed-
lings. Figures obtained from one large producer of tung
oil seedlings are as follows:


Rent of land ----------- $150.00
1000 lbs. of seed (fruit) .....------......-- 300.00
Hulling seed 49.55
Fertilizer (to Sept 1st.) -- 244.40
Preparation of land ..---.----- ...- 187.50
Planting ---------- -- .---- 29.70
Cultivation and hoeing 143.38
Application of fertilizer ... ------- -------- 60.48
Supervision (10'/ on cost exclusive of seed) 86.60

Total cost to Sept. 1st $1,251.51
Following is the estimated cost to Jan. 1st:
Fertilizer (Sept. application) ----- $ 60.00
Sept. (including fertilizer) -- 50.00
Oct., Nov., Dec. (cultivation only) ----.------- 90.00
$ 200.00
Add cost to Sept 1st. ---- -- --1,251.51

Total cost of removal from nursery $1,451.51

The estimate on the number of trees produced by the
above 1,000 lbs. of fruit, after allowing for throw-outs, was
40,000 trees. This would indicate an actual production
cost of $0.0363 per tree to time of transplanting. To this,
however, there should be added the cost of digging, inspec-
tion, tagging, and loading on trucks for shipping, which
might bring the cost to from 71/ cents to 10 cents per tree.
The cost of delivery on trucks for distances up to 200
miles might be as high as 6 cents per tree, and to the above
there would be added a reasonable figure for general over-
head, advertising, and profit.

Figures from another 30 acre nursery south of Gaines-
ville, which purchased multiple cluster fruit at 30 cents per
pound, indicate a base cost of a little less than 4 cents per
tree for the seed, for hulling the seed, for preparing the
land, planting, cultivating, and fertilizing. The fertilizer
used in this instance was a 5-8-5 bone and phosphate mix-
ture purchased at $46.00 a ton, and this was plowed in the
nursery before the seed was planted. A small amount of
nitrate of soda was later used. To this figure there would
necessarily be added from 3 to 4 cents per tree for digging,
pruning, and other grove expenses.


The above figures do not include the overhead necessary
in the form of payroll for the experts who would be re-
quired to properly grow nursery trees. General overhead,
advertising, and a fair profit might in every instance bring
up the selling price from 15 to 25 cents per tree in large
quantity, according to size.

It should furthermore be stated that when trees are
selected from a nursery, those which caliper from a half to
three-quarters of an inch, and which constitute the best
size for planting, may not run two- thirds of the best trees
in the nursery. The culls and similar trees which must be
left over for the next year may run well over-one-third of
the trees in any nursery. Large well formed stock nat-
urally command the highest price.


The following resolution was sent to Dr. David Fairchild
at his home in Coconut Grove, Florida, as a result of a
resolution adopted at the First National Meeting of the
Tung Oil Industry, held in Pensacola, Florida, April 3, 1935.

"By resolution unanimously adopted I am directed to wire
you expressions of appreciation and recognition of your im-
portant service in bringing to America the first tung oil
seed and arranging for its planting. From this small begin-
ning during your connection with the U. S. Department of
Agriculture, an important industry has grown. Action was
today taken for the formation of a National Association of
the American Tung Oil Industry which we believe is destin-
ed to supply for the future the complete needs of industry
for this essential raw material and thus accomplish' a furth-
er most important step in the economic independence of

Dr. Fairchild's reply will be interesting to all who attend-
ed the Pensacola meeting and to others who are in any way
connected with the American Tung Oil Industry: It is as

J. C. Adderley, Chairman,
First National Tung Oil Conference,
Pensacola, Florida.
Dear Mr. Adderley:


It is a great pleasure to know that the Tung Oil trees
which my colleagues and myself scattered through the
Southern States and across the continent to California have
found their home and have begun to make their way in
the commercial world. I could wish that some of those who
played parts in the care and watching of the early trees
were alive today to feel the thrill that I do when I hear of
new milestones in the progress of the Tung Oil Industry
being made.

The transplanting of such an industry from the Orient
to our shores marks a significant feature in the changing
agriculture of our time and the romance of its beginning
is ample payment for all the labor and anxiety which my
friends and I bestowed upon it at a time when many spoke
of it as a silly, foolish dream.

I had the pleasure of knowing the great pioneer of
the Plantation Rubber development of the East Indies and
possess still a bit of rubber which he drew for me as latex
from a seed tree in his garden in Signapore in 1896. It has
been my pleasure to see develop the whole rubber tire indus-
try and the spread of millions of acres of the Brazilian Rub-
ber tree in the Orient since that time.

This pioneer is still alive, Dr. H. N. Ridley, of Kew,
England; and it is hard to realize what has happened to
the world since he complained to me in Signapore, that no-
body would plant Hevea rubber trees because there was
no future in plantation rubber. Today there is a crisis in
plantation rubber because of over production.

I trust that your new National Association of the Ameri-
can Tung Oil Industry will stabilize the whole planting
phases of the industry in such a way that lands unsuited to
the growth of the tree, situated in regions that do not have
the necessary climatic character, will be eliminated from
consideration. In my very first speech on Tung Oil Trees,
before the Paint and Varnish Makers Association I empha-
sized the fact that my interests were strongly on the side
of the man who risks his life and land and fortune in the
growing of the crop.

I thank you heartily for the honor that your new Ameri-
can Association has seen fit to bestow upon my colleagues


and myself. Trusting that you will keep me informed with
regard to the progress of the Association, I remain,

Very sincerely yours,
(Signed) David Fairchild,
Agricultural Explorer."


Tung Oil appears to present the greatest promise of ex-
pansion among the commercial drying oils surveyed. In the
formulation of many products in which linseed oil alone was
formerly used, blends of tung oil and linseed oil are now
employed. This practice, which is becoming general, indi-
cates that in many instances, tung oil has replaced linseed
oil as a supplementary material of distinctive properties.
The greater recognition of the necessity and value of quick
drying finishing materials in mass-production manufactur-
ing has stimulated interest in tung oil and has resulted in
its more extensive and more satisfactory application in
varnish manufacture.

In this field linseed oil was formerly the predominant raw
material. Tung oil has been substituted in some other cases,
but it imparts to the finished product many desirable char-
acteristics which could not be obtained with linseed oil. Re-
search investigations are bringing to light many new uses
for tung oil, and with the prospect of domestic production
of a better quality of oil in commercial quantities, further
expansion of consumption seems assured, which may in a
measure affect present linseed oil outlets.-Bureau of For-
eign & Domestic Commerce, Bulletin No. 133.

FThe Hunter Press, Tallahassee, Fla.

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