Jan. 1,1925 Effect of Height of Chipping on Oleoresin Production 
85 
“scrape” obtained are shown by weight 
in Table II. 
Hack used. —Chipping was done 
with a No. “0” hack, a tool smaller 
than that generally used. With this 
it is easier to cut a light chip. 
Depth of chipping. —All 60 trees 
were chipped to the same depth, nomi¬ 
nally one-half inch, which has been 
found successful with this type of 
timber. ‘ 
Heights of chipping compared.— 
On the 20 trees in Group 1 a chip as 
nearly as possible 34 inch high was 
Temoved each week. This is much less 
wood (in the vertical direction) than is 
now removed in ordinary commercial 
chipping, though frequently a chip no 
higher than this will be removed when 
the faces are high and a “puller” 7 has 
to be used. 
The 20 trees in Group 2 were chipped 
34 inch high each week, according to 
the standard practice of the Forest. 
So skilled have the chippers on this 
forest become that when using an “0” 
hack they easily and accurately carry 
on this light chipping and even tend 
to remove a chip slightly less than J4 
inch high. Such chipping has already 
been found to produce desirable results 
on a commercial scale. 8 The Group 2 
test chipping averaged 0.45 inch for 
the 1923 season. (See Table I.) 
On the 20 trees in Group 3, “high” 
chipping, z /i inch per week, was prac¬ 
ticed. This corresponds to work now 
being done in many commercial oper¬ 
ations 
Width of face. —The average width 
of the face at the end of the 1923 season 
was 9.6 inches for Groups 1 and 3 and 
9.3 inches for Group 2. 
With the overcoming and adjusting 
of the few slight difficulties and irregu¬ 
larities described above, the test pro¬ 
gressed very satisfactorily to the end of 
the season, and has been resumed in 
1924. In Plate 1 are shown typical 
faces as thev appeared on November 
24, 1923. 
YIELD OF GUM IN RELATION TO 
HEIGHT OF CHIPPING 
RESULTS FROM THE TEST 
In Table II are recorded the weights 
of gum obtained from the three groups 
of trees during the 1923 season. The 
average yield per streak per tree at 
each dipping is exhibited graphically 
in Figure 1. 
With the yield of Group 1 taken as a 
standard, Group 2 fell below it 8.4 per 
cent in amount of gum (dip) obtained 
and 7.2 per cent in amount of dip and 
scrape combined. Group 3 as com¬ 
pared with Group 1 was 10.5 per cent 
lower in dip but only 4.9 per cent lower 
in combined dip and scrape. With 
Group 2 (Forest Service practice) 
taken as a standard, Group 3 (common 
commercial practice) fell 2,5 per cent 
below in yield of dip; but if dip and 
scrape combined are considered, Group 
3 was 2.7 per cent higher (for the first 
year) than Group 2. 
Table I.— Average height of faces desired and obtained in a chipping test on long- 
leaf pine , Camp Pinchot , Fla., 1923 (measured on 32 streaks) 
Height of cut 
Group 1 
Group 2 
Group 3 
Total height face (inches): 
Contemplated __ ____ 
8.0 
16.0 
24.0 
Actual _ __ 
10.7 
14.4 
21.4 
At test rate _ - _ - 
“9.2 
14.4 
& 22. 9 
Average height streak (inches): 
A sked _ 
0. 25 
0.50 
0. 75 
Obtained __ 
0 . 28 
0. 45 
0.71 
* Actual height minus 1.5 inches extra height cut during first 6 weeks of chipping, when a streak y 2 inch 
high was cut each week. 
b Actual height plus 1.5 inches. During first 6 weeks of chipping the face was cut 6/4 inches too low since 
each streak was l / 2 instead of % inches high. 
7 With the puller the cutting of the streak is done by the muscle power of the chipper, whereas with the 
hack the weight on the end of the handle makes it seem easier to cut the streak. This accounts for the 
fact that less wood is removed during pulling. 
s McKee, E. R. op cit. 
EXPLANATORY LEGEND FOR PLATE 2 
Cross sections of chips cut Nov. 24, 1923 (end of season), from Groups 1 and 3. Longest sections show 
about y 2 inch of wood. 
Top row.—Chips from low faces, Group 1 trees. Note (1) wide 1923 annual ring next bark, at top, (2) 
with numerous resin passages; (3) most of the 1923 rings as wide as or wider than those of 1922. 
Bottom row.—Chips from high faces. Group 3 trees. Note (1) narrow 1923 annual ring next bark, (2) 
with few resin passages; (3) 1923 annual ring often narrower than that of 1922. 
