OLEORESHST PRODUCTION. 37 



DESIRABLE PRACTICES. 



Ideal chipping should be deepest at the shoulder and shallowest at 

 the peak or most exposed portion of the face, at which point the least 

 normal and most harmful conditions, with respect to the vitality of 

 the trees, are most likely to develop. 



Keeping the gum clean means high grades of rosin; hence it is 

 well to cover the cup with a paddle during chipping (PL IV, fig. 4) , 

 or to equip the " puller " with a chip catcher (PL IV, fig. 6) , to 

 keep fragments of bark out of the gum during chipping and to avoid 

 filling the cups with trash which will increase the apparent volume 

 of the dip. 



DIPPING. 



Frequent collecting of the gum or dipping insures higher yields 

 of turpentine. 35 Some advocate scraping off the hardened gum, or 

 scraping with the paddle at each dipping instead of allowing it to 

 remain until the end of the season and removing it all at once as 

 was done in figure 4, Plate I. It is maintained that the latter prac- 

 tice exposes the surface to undue drying, and that harmful cracking 

 and checking may take place. Furthermore, the longer the scrape 

 remains on the tree the greater is the reduction in the amount of 

 turpentine which it will yield. A real reduction of waste may be 

 obtained by using tight dip barrels. On one operation gasoline 

 barrels were employed. Ideal dip containing about one-third more 

 turpentine than usual was obtained by using closed glass cups for 

 holding the gum as it exuded from the tree, but these were found to 

 be very difficult and expensive to operate. 



YIELDS.. 



It would appear as if under proper operating conditions more gum 

 should be obtained at least during the second and third years than 

 during the first, for many more resin passages are present. This, 

 however, is not ordinarily the case in the United States. 36 On the 

 Columbia, Miss., experiment the narrow chipping nearly held its 

 own the second year, but during the first year the total yield, without 

 reference to the amount of chipping surface used, was lower than the 

 yield from the standard. 37 It seems entirely possible that an optimum 



* In India dipping 1h as frequent as cblpplng. The same workor docs both and is paid 

 on the basis of the gum produced. One worker chips (by Hie French method) about 1,000 

 or channels in ft days. 



"•Since thin was written, information has been obtained from Mr. F. Canning) con- 

 ■errator of forests, India, concerning turpentine operation* i>y the ITrencb method (very 

 conservative chipping) <>n Pinu$ longifoUa in i be Kniinion Bills in the Onlted Provinces, 

 to tiie effect that, as a rule, more gutn Is obtained the second, third, ana" fourth yean than 

 the first. The yield the fifth year is about the same as that obtained during the Brat. 



"Data from the Florida National Fores! experiments about to be published are al p 

 of Interest In thii connection. 



