Plastic apron-gutter will improve gum grades for naval stores producers / by Grady Williams and Ralph W. Clements

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GEORGIA FOREST RESEARCH PAPER

20
JULY, 1981

PLASTIC APRON-GUTTER WILL IMPROVE

GUM GRADES FOR NAVAL STORES PRODUCERS

BY
GRADY WILLIAMS AND RALPH W. CLEMENTS

Received

MAY 3 1988

" GEORGIA^ FORESTRY,
%s^

RESEARCH DIVISION

DOCUMENTS UGA LIBRARIES

GEORGIA FORESTRY COMMISSION

AUTHORS

RALPH W. CLEMENTS was Naval
Stores Research Specialist with the
USDA Forest Service, Southeastern
Forest Experiment Station, Olus-
tee, prior to his retirement in 1980.
He was awarded the USDA
Superior Service Honor Award in 1962 and 1980.

ggCJSS^
GRADY WILLIAMS is Gum Naval
Stores Specialist with the Georgia Forestry Commission, McRae,
Georgia. He received his BS degree in Forestry from the University of
Georgia.

PLASTIC APRON-GUTTER WILL IMPROVE
GUM GRADES FOR NAVAL STORES PRODUCERS
BY
GRADY WILLIAMS AND RALPH W. CLEMENTS

ABSTRACT

Iron cups and gutters are the two major sources of contamination which de-
grade gum and produces inferior rosin. The Georgia Forestry Commission and the U.S. Forest Service, USDA, recogniz-
ed this problem and cooperated in re-

search to test new materials and improve the gum collection system. The one-piece
plastic apron-gutter described herein will eliminate iron contamination and sulfuric acid will not attack the polyethylene
material. The new gutters are easy to in-

DBH stall on trees 9 inches

and larger.

With reasonable care, the plastic system

should last as long as the average turpen-

tine face is worked and will always yield

top grades of gum.

INTRODUCTION

The oleoresin, often called crude gum, extracted from living pines has been a periodic cash crop for many Georgians since 1800. In 1980 about 85 percent of the United States' production came from slash and longleaf pine forests in south
Georgia. Old production practices and the use
of outdated supplies have lowered gum
grades to the point that the industry is
searching for new materials and better collection practices. The plastic apron-
gutter described here will enable naval
stores producers to make better grades
and receive higher prices for their crude gum.
Nature has provided slash and longleaf pines found in the Southeast with the highest quality of any oleoresin in the world. Through distillation at processing
plants, crude gum yields turpentine, a
liquid, and rosin, a viscous sticky material. Rosin has the greater value. Proces-
sors buy crude gum by weight and grade,
and grade is determined solely by color of the crude gum. Generally, a given grade

of crude gum will produce the same color

grade of rosin. In both cases, pale colors

are the highest in value and dark the low-

est. Seven colors or grades are recognized:

WW WG X (Extra),

(water white) and

(window glass)

are pale colors; N

(Nancy) is intermediate; and M (Mary),

K (Kate) and I (Isaac) are dark colors.

Turpentine is not distinguishable by color

grade.

About 99-percent of the trees worked

for gum in the United States are treated

with a sulfuric acid paste or spray to stim-
ulate gum flow. Cups, aprons and gut-

ters of galvanized iron have been standard
for collecting gum since about 1910.

Since the introduction of acid stimulation
in the 1950's, however, both gum pro-

ducers and their field workers have ob-

served that galvanized iron and sulfuric
acid are not compatible. Too much sul-

furic acid applied to the streak will run
down the face onto the iron gutters and

into collection cups. It destroys the pro-

tective zinc coating, exposing base iron;
iron contaminants mix with the gum and

cause it to turn dark in color. The darker color reduces the grade of the gum and the rosin made from it. Only a small amount of iron rust from cups or gutters lowers rosin quality by three grades, and iron gutters deteriorate rapidly when sul-
furic acid is used.
The Naval Stores Market News pub-
lished by USDA Agricultural Marketing
Service reported that less than 40 percent of the annual gum production for the
crop year 1979-80 graded X, WW, and WG, the three top grades. To improve gum grades, the industry needs aprons
and gutters that will resist the corrosive action of sulfuric acid and withstand abuse from installing and dipping.
The Gum Naval Stores Production
Unit of the Southeastern Forest Experi-
ment Station at Olustee, Florida, and the
Research Division of the Georgia Forestry Commission have been experimenting since 1977 with thermoplastics in an effort to develop a one-piece plastic apron-
gutter for use in commercial gum produc-
tion.

Figure 1. - One-piece plastic apron-gutter

THE NEW PLASTIC
APRON-GUTTER
The new plastic apron-gutter, now in its second year of use, is made of poly-
ethylene. It incorporates the geometric features of a center apron for balancing the cup and left and right gutter sections
for channeling the gum from each side onto the apron and into the cup. The
front cover shows the one-piece plastic apron-gutter correctly installed.
Sulfuric acid, in paste or solution, will
not corrode or damage the polyethylene plastic apron-gutter. The molded aprongutter is relatively tough. With normal dipping, handling, and abuse in the woods, the new apron-gutter should remain serviceable for at least 4 years.

INSTALLATION AND USE
The apron-gutter features a notch in the outer lip of the apron section, enabl-
ing the gutter to be flexed to fit trees of different sizes. Normally, six nails will attach the apron-gutter firmly to the tree if the bark has been properly smoothed with a rossing tool. Correct positioning of the nails for installation of the apron-
gutter is shown in Figures 1 and 2. To obtain a tight leakproof fit on large
trees with nearly flat surfaces, and on trees with irregular surfaces, the outer
ends of the gutter should be pulled down
slightly and twisted toward the tree before nailing on the shoulders. It will fit
trees 9 inches DBH and larger. A face up
to 12 inches wide can be accommodated

(Fig. 3). The plastic in the apron-gutter is flexible, even in cold weather, and can be shaped to fit tightly on most cylindrical
surfaces.
Polyethylene plastic apron-gutters have proven to be durable and reasonably tough. However, they can be punctured or split by careless installation or handling. These gutters contain pre-punched
holes to prevent splitting and make driv-
ing of nails easy. Double-headed nails, especially those at each end, should not
be driven too tight. Gum can be punched
from the plastic apron-gutter and the unit elevated in the same manner as metal aprons and gutters (Fig. 4). The ends of the apron-gutter are capped to provide rigidity to the outer lips and to prevent
gum from backing off the ends as waste.

AVAILABILITY AND
ECONOMIC IMPACT
The new plastic apron-gutter described here is manufactured and marketed by
the Lerio Corporation of Valdosta,
Georgia, and Mobile, Alabama. A total of
36,000 molded gutters were installed in 1980 by selected producers in Mississippi, Alabama, Florida and Georgia to test performance and durability. The plastic apron-gutter costs a few cents more than metal gutters, but the plastic system always yields top grade gum.
Gum flows uncontaminated from the
pine tree, perfectly pure and clean. Con-

tamination and loss in value are caused by

an outmoded and incompatible collection

system. Plastic apron-gutters and cups

will eliminate two major sources of the

metal contaminates which degrade gum

and produce inferior rosins. Naval stores

producers should notice the economic

impact of this new invention on market

prices immediately.

The average price difference between
WW and N gum is usually about $12.00

per standard barrel. Based on the volume
of gum produced by grades for the crop

year, it is estimated that the production

WG of X, WW, and

gum could be increas-

ed by at least 25 percent.

SUMMARY
Georgia gum producers will find that
plastic apron-gutters are tough, easy to install, and acid resistant. There will be no
iron rust contaminates in gum from cups
or gutters to lower grade and market price. With reasonable care, the one-piece plastic apron-gutter should last as long as the average turpentine face will be worked. Both producers and processors should profit from the development and use of
this apron-gutter.

Figure 2. - Cup should fit snug against tree and very tight under apron section.

38
Figure 3. -Cup should be level under apron section. The one-piece plastic apron-gutter will accommodate a streat 12 inches
wide as shown on this 12-inch DBH tree.

3

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DMMM

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Ebfl?

Figure 4. - One-piece plastic apron-gutter, plastic cup and nails are shown in the elevated position. Be sure outer ends are raised enough to cause gum to flow onto apron section.

GEORGIA
FORESTRY
A. Ray Shirley, Director
John W. Mixon, Chief of Forest Research