UNITED STATES DEPARTMENT OF AGRICULTURE 



MSI BULLETIN No. 567 



"-^MaO^'aM'S? Contribution from the Forest Service "*§3/l/\SV4g!^ 



Contribution from the Forest Service 

 HENRY S. GRAVES, Forester 



Washington, D. C. 



PROFESSIONAL PAPER 



October 2, 1917 



INCREASED YIELD OF TURPENTINE AND ROSIN FROM 



DOUBLE CHIPPING. 



By A. W. Schorger, Chemist in Forest Products, and R. L. Pettigrew, 

 Assistant Engineer in Forest Products. 



CONTENTS. 



More naval stores from the same tree. . 



Plan of the experiments 



Yields 



Effect of double chipping on the trees . 



Practicability of double chipping 



Returns from double chipping, in dollars 

 and cents ■ 



6 Summary . 



MORE NAVAL STORES FROM THE SAME TREE. 



Naval-stores operators have the chance to get 31 per cent more 

 turpentine and 36 per cent more rosin from their trees by increasing 

 the number of chippings during a season. This has been determined 

 by actual experiments made by the Forest Service on a tract in 

 Mississippi, the results of which are presented in this bulletin. 

 Briefly, the method that gives the increased yields is to chip twice a 

 week instead of once. At the same time, the streaks are cut only 

 one-fourth inch high instead of one-half inch, the present standard 

 practice. The faces, therefore, are no higher at the end of the 

 season than when they are chipped once a week. 



Double chipping, of course, entails extra expense, but this is much 

 more than offset by increased returns. With all additional expenses 

 taken into account, and in the light of present prices, double chip- 

 ping ought to increase the net profits from a crop (10,000 faces) by 

 about $450. This means an increase in net profits from a 50-crop 

 operation of about $22,000. 



While the experiments reported in this bulletin actually show 

 a large increase in yields and revenue as a result of double chipping, 

 it must be borne in mind that they cover only the first year's opera- 



991C3°— Bull. 567—17 



