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. 



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