24 



BULLETIN 229, U. S. DEPARTMENT OF AGRICULTURE. 



Table 13. — Comparison of the amount of swape formed by the cup and box systems, 



season 1902, Georgia. 



Half crop. 



Net weight 

 of scrape. 



Net weight 

 of dip. 



Total 

 weight of 

 : 'gum"dip 

 and scrape. 



Percentage 

 of scrape. 



First year: 



Boxes 



Cups 



Second year: 



Boxes 



Cups 



Third year: 



Boxes 



Cups 



Fourth year: 



Boxes 



Cups 



Pounds. 

 10,315 

 13,155 



17, 120 

 12, 210 



8,580 

 7,200 



7,970 

 6,635 



Pounds. 

 42,787 

 51,081 



35, 700 

 42,630 



15,435 

 28,245 



14,385 

 25, 305 



Pounds. 

 53, 102 

 64,237 



52,820 

 54, 840 



24,015 

 35,445 



22, 355 

 31,940 



Per cent. 

 19.4 

 20.5 



32.4 

 22.3 



35.7 

 20.3 



35.6 

 20.8 



ape is troublesome to collect, yields a low grade of resin, and 

 but 11 per cent of turpentine on distillation, while gum col- 



Scra-j. . 

 gives but 11 per cent of turpentine on distillation, while gum col- 

 lected by the cup system yields about 19 per cent of turpentine. 



RELATIVE YIELDS FROM DIFFERENT DEPTHS AND HEIGHTS OF 



CHIPPING. 



In the years 1905 to 1908 the Forest Service carried out experi- 

 ments to determine the effect of the depth and height of chipping on 

 the yield of resin. Four crops 1 were used in the experiment, desig- 

 nated A, B, C, and D, respectively. 



Crop A, taken as the standard, was chipped in the ordinary way, 

 the average depth of chipping being seven-tenths of an inch and the 

 average height five-tenths of an inch. 



Crop B was used to test the effect of shallow chipping, the average 

 depth being four-tenths of an inch. 



Crop C served to show the effect of narrow chipping, the average 

 height being four-tenths of an inch. 2 



Crop D was turpentined with reference to the possibilhy of work- 

 ing the turpentine a second time. The present method consists 

 in exhausting the tree within four years. This crop was chipped 

 in the same manner as crop A, but the minimum diameter of the 

 trees turpentined was limited to 10 inches, as compared to a mini- 

 mum diameter of 6 inches in crop A; in addition the minimum diame- 

 ter of the tree to bear two faces was raised from 13 inches in A to 

 16 inches in crop D; no tree in crop D had more than two working 

 faces. 



Table 14 shows the yields from the four crops A, B, C, and D. 



1 Crops of 8,000 faces each were used. 



a It was intended to have the height of chip in "C" half that in "A," but in spite of close supervision 

 the chippers cut wider than was desired. 



