OLEORESIIST PRODUCTION. 27 



the marked reduction occurring during the three years of turpen- 

 tining is very apparent, although some allowance must be made for 

 the fact that the greatest reductions in ring width after turpentining 

 generally occurred in the trees with very wide rings, hence at least 

 a part of the reduction noted might be attributed to this character- 

 istic. 25 In general, it may be said that wherever trustworthy evi- 

 dence is obtained it points to the conclusion that conservative chip- 

 ping which does not unduly reduce the vitality of the tree, leaving 

 unturpentined trees that are too small, not overcupping, and leaving 

 sufficient bark bars pay in point of yields obtained and in reducing 

 the number of trees which are killed or which dry- face. 



EARLY FOREST SERVICE EXPERIMENTS. 



Evidence pointing to the advantages of conservative chipping is 

 also to be found in the results from some experiments carried on 

 from 1905 to 1908. 26 The standard chipping of a commercial tur- 

 pentine company not far from Jacksonville, Fla., was in this case 

 used as a basis for comparison. It was slightly heavier chipping 

 (streaks 0.6 to 0.7 inch deep and 0.51 inch high) than the standard 

 chipping practiced in 1916 and 1917 at Columbia, Miss. Both slash 

 and long-leaf pine were found in the stands of timber used. It was 

 noted that the slash pine produced little or no scrape. The purpose 

 of the work was to determine the results to be obtained from (1) 

 shallower chipping, a reduction of depth of cut from 0.6 or 0.7 inch 

 to 0.4 or 0.3 inch, the shallowest cuts being used on the slash pine ; 

 (2) narrower chipping, an intended reduction in height of one-half, 

 which was. however, in practice a narrowing from 0.51 to 0.4 inch; 

 and (3) light cupping, the cutting of fewer faces, and the elimina- 

 tion of turpentining of very small trees with a view to a second tur- 

 pentining at some future time. 



It was reported that considerable difficulty was found in obtain- 

 ing exact and uniform chipping, because of the change of chippers 

 from time to time on the different crops. Another possible source 

 of some error in the results was the method of determining the 

 illative yields from the different crops by weighing the dip and 

 scrape instead "f the turpentine and rosin distilled from it. This 

 mi i hod was found to be misleading in the case of the results ob- 

 tained at Columbia, Miss., where it was found that a high weight- of 

 crude gum might he partly due to water mixed with the gum during 

 rainy periods, and that it did not always indicate a proportionally 



high yield of turpentine and rosin (Table 5). 



?*A publication l« In preparation l»y the Pdreal Service on the detailed resoll 

 relative yield from i ii<- dlfferenl types of experiment*) chipping practiced <<n this tract. 

 I or. Berv. I'.ui. mi, p. 16. 



