28 
BULLETIX 1064. U. S. DEPARTMENT OF AGRICULTURE. 
Table 7. — Early Forest Service experiments — Summary of total yields for 
1905, 1906, 1907. and 1908 on the oasis of the corrected amounts of dip and 
scrape {125 cMppings). 
[Data from U. S. Department of Agriculture, Forest Service Bulletin 90.] 
Dip (oleoresin;. 
Scrape (hardened 
oleoresin;. 
S2 1 "-" 
Average 
depth of 
chip- 
pings. 
Dead 
trees 
at 
Ber cent of 
stand. 
Crop. 
Yield. 
1 ♦ 
Yield. 
In- De- 
crease.' crease. 
: 
berof 
chip- 
pings. 
height 
of 
chip- 
pings. 
end of 
sec- 
ond 
sea- 
son. 
Long 
leaf. 
Slash. 
A. Standard chipping 
of Walkill Turpen- 
tine Co. 1 
206, 23.' 
211, 911 2. 75 
214,503, 4.01 
279, 260 35. 41 
! 
47.74- 
44,838 
39, 775 
53, 915 
125 
123 
124 
119 
Inches. 
0.51 
.51 
.40 
.51 
Inches. 
2 0.7 to 0.6 
2 0.4 to 0.3 
2 0.7 to 0.6 
2 0.7 to 0.6 
121 57 
43 
B. Shallow chipping. 
C. Narrow chipping. . 
D. Reduced number 
of faces, larger trees, 
prospect- of back 
12. 93 
6.08 
16.69 
73 
64 
58 
48 
46 
51 
52 
54 
49 
i Minimum diameter of turpentined trees 6 inches, 2 faces permitted on trees over 13 inches. 
2 Shallower cuts on slash. 
s Minimum diameter of turpentined trees 10 inches, 2 faces permitted on trees over 16 inches. No more 
than 2 faces per tree. 
A summary of the results obtained is given in Table 7. It is ap- 
parent that crop A (standard) showed a successive yearly decrease 
in yield and the greatest number of dry-faced and dead trees. 
Crop B, the shallower chipping, showed in the four years of oper- 
ation an increase in yield of about 3 per cent over the standard. 
This gain took place during the last two years of the operation. 
There was less relative yearly decrease in yields also than in crop A. 
and less scrape was formed, which fact, the writer pointed out. was 
in accord with the current idea that deep chipping produced much 
scrape. From these results it is concluded in Bulletin 90 that there 
is "' no doubt as to the wisdom of shallow chipping/' 
In sharp contrast to this were the results from an operation visited 
in 1917 in Mississippi. The type of timber and the method of chip- 
ping employed are illustrated in Plate VH, figures 5. 6. and 8. The 
streak cut was about 0.75 to 1 inch in depth and a scant 0.5 inch in 
height, and a very high as well as a sustained yield was reported. 27 
These trees were characterized by having very wide sapwood. Less 
than 1 per cent of the trees were lost through death from turpentin- 
ing. Care and good judgment were exercised in the placing of the 
cups and in maintaining adequate bark bars between the faces on 
this timber. 
It would appear from the foregoing that the question of the width 
of the sapwood and the responsive vio-or of the timber on any given 
tract must be considered as of fundamental significance in determin- 
ing the depth of the streak to be cut. That the resin passages in a 
27 Reported yield of 105 barrels of turpentine per yearling crop and an average of 82 
barrels for different age-, including- virgin and fourth-year workings. 
