46 BULLETIN 1064, U. S. DEPARTMENT OF AGRICULTURE. 
Turpentining a given tract should, however, be planned far enough 
in advance of the cutting of the trees to insure the obtaining of the 
full advantage of at least a four to six year operation, instead of 
the sawmill demand forcing the timber to be cut at the height of 
its gum-producing power. 
Many other problems, involving the further development of needed 
improvements in practice, and also many related to a better under- 
standing of the imperfectly known physiological processes funda- 
mental to oleoresin production, await investigation. 
ADDITIONAL COPIES 
OF THIS PUBLICATION MAY BE PROCURED FROM 
THE SUPERINTENDENT OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
WASHINGTON, D. C. 
AT 
20 CENTS PER COPY 
