30 
BULLETIN 1064, U. S. DEPARTMENT OF AGRICULTURE. 
and too numerous faces, which unduly reduce the relative percentage 
of uncut bark, are unquestionably harmful and unprofitable. The 
questions of depth and height of streak are intimately connected with 
the number of faces and the returns obtained, but further work is 
needed, as has been shown, to fix within narrower limits the range 
of the most successful depth and height of chipping. It is stated 
by careful operators that, at the very least, one-third of the bark 
should remain uncut, and undoubtedly a larger proportion is de- 
sirable. The area D at Walkill was so turpentined that it would be 
possible to work it for a second period (back cup) some time later. 
Table 8. — Yield at first clipping from trees of different diameters. 
Set 1. 
Set 2. 
Diameter breast high 
(inches) . 
Width of 
face 
(inches). 
Yield 
(average 
of 15 
trees). 
In pea- 
centage 
of 10-inch 
trees. 
Yield. 
5 
Ounces. 
Ounces. 
4 
6 
6 
7. 
7 
8 
9 
H 
10 
10 
10 
15 
19 
22^ 
23 
24 
44 
67 
84 
100 
102 
1 107 
si 
11 
8 
9. 
14 
10 
16i 
19 
11 
12 
21 
!4 trees. 
Table 9. — Gain obtained 
light cupping as compared ivitli Standard chipping 
at Walkill, Fla. a 
Dip. 
Increase. 
Last three years compared to first. 
Year. 
A, stand- 
ard. 
D, light- 
cupped. 
Pounds. 
Per cent. 
A 
Increase. 
Decrease. 
Increase. 
Decrease. 
1905 
Pounds. 
63,615 
64, 583 
43,675 
34, 362 
Pounds. 
73, 704 
84,074 
69, 286 
52,196 
10, 089 
19, 491 
25,611 
17,834 
16 
30 
58 
52 
1906 . 
b H 
bu 
1907... 
31 
46 
6 
1908. . 
29 
a For. Serv. Bui. 90, p. 20. 
b This increase was chiefly due to the fact that in 1905 there were 31 streaks and in 1906, 35 streaks cut. 
Because of the gains secured in the first three years of the Walkill 
experiments, a different experiment was instituted on two crops 
during the fourth year (1908), which combined both the shallow 
and the narrow chipping features. " Yearling " or second-year 
crops were used, and the yields of gum were compared with those 
from a similar adjacent crop chipped by the standard method. An 
increased production of about 35 to 38 per cent was secured in this 
experiment. The " dip " from these shallow and narrow-chipped 
