EFFECT OF HEIGHT OF CHIPPING ON OLEORESIN 
PRODUCTION 1 
By ELOISE GERRY 
Microscopist, Forest Products Laboratory, Forest Service , United States Department 
of Agriculture 
INTRODUCTION 
“Gum,” as the'oleoresin from the 
living slash and longleaf pine trees of 
the southern United States is called, 
is obtained by cutting a gash or 
“ streak ” across the grain of the outer 
sapwood at the butt of the tree. The 
depth into the tree to which this cut 
extends and the height of the chip of 
wood removed have varied in com¬ 
mercial practice, and still vary widely. 
A new cut has to be made, generally 
at weekly intervals, to freshen the ex¬ 
posed surface and secure a flow of gum. 
The successive cuts or chippings, one 
close above the other, constitute the 
“face.” (See PL 1.) During a sea¬ 
son’s work, generally between March 
and December, about 32 chippings or 
streaks are cut. 
The objection of some timber own¬ 
ers to turpentining virgin timber is 
due to the very injurious methods of 
chipping which have prevailed all too 
widely. A large amount of timber has 
been killed, injured, or at least its 
grade unnecessarily lowered, in this 
way. 
For some time past the Forest Serv¬ 
ice of the United States Department of 
Agriculture has been testing operating 
methods for the purpose of determin¬ 
ing ways of improving turpentine pro¬ 
duction and at the same time of con¬ 
serving timber. The administration 
of the Florida National Forest has in¬ 
deed demonstrated over a considerable 
period and on a commercial scale the 
beneficial results that can be obtained 
on mature longleaf pine timber by the 
use of a streak which removes a chip 
}/2 inch deep and 3^ inch high each 
week, 2 a more conservative practice 
than that obtaining in many private 
operations. Tests were also started 
in 1923 and are now under way at the 
substation of the Southern Forest 
Experiment Station at Starke, Florida, 
to determine the effect of different care¬ 
fully controlled methods of chipping 
on second-growth slash and longleaf 
pine. 3 The test reported here is one 
of still another series 4 which has been 
conducted for a number of years by 
Dr. Austin Cary, logging engineer 
(Branch of Forest Management), in 
which the writer and, in this case, 
Deputy Supervisor E. R. McKee and 
W. H. Graham, commercial turpentine 
operator on the Florida National 
Forest, also cooperated. Both in tests 
and in commercial turpentining many 
indications have pointed to the fact 
that removing less wood produces con¬ 
ditions in the tree which favor high 
sustained production. 5 “Low” chip¬ 
ping permits a reduction in the size 
of the scar cut each year, thus lessen¬ 
ing the amount of possible degrade. 
It also lengthens the time during which 
a given crop may be operated, if so 
desired. 
Therefore, since the results from 
“low” chipping indicated decided oper¬ 
ating advantages, but since no data 
on directly comparable stands were 
available over a sufficiently long period 
to be conclusive, the turpentining test 
described herein was instituted. It 
was conducted in connection with an 
actual commercial operation, the chip¬ 
ping being done by the regular worker 
assigned to the tract, and the gum, 
after being weighed, was collected and 
stilled together with the other gum 
1 Received for publication July 23, 1924. A report of a test made by the Forest Service in 1923 to deter¬ 
mine the effect of different heights of chipping in turpentining longleaf pines. 
2 McKee, E. R. naval stores production on the Florida national forest. Naval Stores Rev. 
33 (6): 16-17; (7) 6, 23; (8) 6,19; (9) 10, 23; (10) 16-17. 1923. 
3 Wyman, L. forestry tests at staske, Florida. South. Lumber Jour. 50 (7): 26c-26d. 1924. 
* Cary, A. studies on flow of gum in relation to profit in naval stores industry. Naval Stores 
Rev., v. 31, no. 34, 36-37, 39-42; v. 32, no. 37, 39, 42, 44, 50; v. 33, no. 38, 40, 44; v. 34, no. 3-5, 8. 1921-1924. 
[Various paging]. 
s Gerry, E. oleoresin production. U. S. Dept. Agr. Bui. 1064, 46 p., illus. 1922. - recent 
observations on the effects of turpentining on the structure of second-growth slash and 
longleaf pines. Jour. Forestry 21: 236-241, illus. 1923. 
Journal of Agricultural Research, 
Washington, D. C. 
(81) 
Vol. XXX, No. 1 
Jan. 1, 1925 
Key No. F-19 
