6 BULLETIN 567, U. S. DEPARTMENT OF AGRICULTURE. 
In Table 4 the total quantities of turpentine and rosin obtained by 
narrow, double, and standard chipping are compared on a percentage 
basis. Double chipping increased the yields of turpentine and rosin 
30.9 per cent and 36 per cent, respectively. The greater increase in 
rosin is due to the heavy yield of scrape. The yields of turpentine 
and rosin were decreased 17.4 per cent and 17.5 per cent, respectively, 
by narrow chipping. It will be noted, however, that the narrow 
faces are only about one-half the height of the standard or double 
faces. The comparative heights of the faces are shown in Plates I 
and II. 
In Table 5 the yields have been arranged with respect to the 
height of face, the widths of all the faces being practically identical. 
On this basis the narrow chipping produced about 40 per cent more — 
turpentine and rosin than the standard. Narrow chipping, however, 
would not be practical in the light of present prices for labor and 
timber leases. 
TaBLE 4.—Comparison of the yields per crop by the various methods of chipping. 
Yield of | Compared : Compared 
Plot. turpen- with pee with 
tine. | sisndard: i standard. ~ 
Gallons. Per cent. Pounds. Per cent. 
Standard chipping ees 22 esearch ea eee 3, 260 100 105, 539 100 
NasrowiGhip pit poe oe oe ets ee ae sem ne tee eee 2, 693 82.6 87, 014 82.5 
Doubleehip pin geese see erate nee Bee Fecha 4, 267 130. 9 148, 542 136 
EFFECT OF DOUBLE CHIPPING ON THE TREES. 
The effect that double chipping will have upon the timber during 
subsequent years of operation must be considered. The same trees 
will be tapped during the coming season, and until the additional 
data are available the advisability of using the method over a period 
of years must remain in doubt. Some data in regard to the severity 
of the several methods, however, will be found in Table 2. By far 
the greater number of faces recorded in this table, especially those 
that had lost from 0 to + the season, were ‘‘dry” faces. This con- 
dition has been the result of old or ‘“‘doty” timber or the direct 
result of turpentining. In the standard chipping a total of 235 
faces, or 38.3 per thousand, were affected. The narrow chipping 
poaemed 223 injured faces, or 32.4 per thousand, while the double 
chipping contained 165, or 54 per thousand. 
This would seem to indicate that double chipping is the severest 
and narrow chipping the least so. However, in the second part of 
Table 1, it will be noted that in the standard chipping there were 
32 faces on trees that had died for no apparent reasons, equivalent 
to 5.2 faces per thousand. For the narrow and double chipping the 
a 
