Jan. i, 1925 Effect of Height of Chipping on Oleoresin Production 
89 
relation between gum production, vi¬ 
tality, and number of resin passages 
present. In Group 1, besides the 
normal number of resin passages in 
the old rings, these relatively more 
abundant extra wound ducts were, as 
is apparent from the plates and Table 
IV, already formed and active by 
midseason. In Group 3 only about 
half as many were functioning at that 
time. Table IV clearly shows that the 
effects of different methods of working 
made a progressive series. The poor¬ 
est formation of wood and resin tissue 
occurred in the Group 3 trees; an 
intermediate but good condition was 
found in Group 2, but the best response 
was made by the Group 1 trees with the 
lowest faces. 
after regular chipping had stopped, a 
thirty-third streak was cut on the test 
trees in order to obtain a comparable 
set of fresh chips on which to study the 
effect of the season’s work at a point 
midway of the streak at the top of the 
face. From Table IV it will be clear 
that a similar, though less marked, 
relation to that found at midseason 
still existed between the groups. The 
average width of the 1923 ring, the 
amount of summerwood, and the 
number of resin passages was greater 
at this time in the Group 1 trees than 
in those of Group 3. There was, it is 
true, a slight increase in the average 
total number of resin passages found 
for Group 3 in November above that 
present in July, but their number was 
Table IV.— Comparative production of wood and resiniferous tissue in height of 
chipping test on longleaf pine, Camp Pinchot , Fla., 1923 
Average width of 
1923 ring 
Average num¬ 
ber of resin 
passages in 
unit area," 
per year 
Number of observations 
in which width of 1923 
ring was found equal 
to, less, or greater than 
width of 1922 ring 
Spring- 
wood 
cells 
Sum¬ 
mer- 
wood 
cells 
Total 
cells 
1923 
Average 
for 3 years 
before 
turpen¬ 
tining 
Equal 
or near¬ 
ly so 
Less 
Greater 
Chips taken July 26, 1923: 
Group 1 (M inch).. 
7.8 
18.3 
26.1 
12.0 
1.10 
Per cent 
31.8 
Per cent 
31.8 
Per cent 
36.4 
Group 2 0A inch)_ 
11.0 
12.9 
23.9 
9.0 
1.08 
5.0 
40.0 
55.0 
Group 3 (H inch).... 
7.8 
6.4 
14.2 
6.5 
1.00 
25.0 
62.5 
12.5 
Chips taken Nov. 24, 1923: 
Group 1 (li inch)___ 
12.6 
19.2 
31.8 
11.4 J 
1.12 
2.7 
32.4 
64.9 
Group 3 {% inch)_ 
8.3 
14.0 
22.3 
7.3 
| 1.21 
11.6 
41.9 
46.5 
“ “Unit area” is an arbitrary tangential extent; the diameter of microscopic field by the width of the 
annual ring observed. Used 32-mm. objective and 15X eyepiece, giving a magnification of about 60 
diameters or 3,600 times the actual wood area observed. 
The time and amount of summer- 
wood formation appear to be signifi¬ 
cant factors in judging the effects of 
given methods of working. Over and 
over again resiniferous tissue has been 
found to be produced at the expense of 
summerwood formation. This is often 
very striking in the case of trees worked 
too severely. The production of early 
and abundant summerwood has been 
found, so far as the writer’s observa¬ 
tions extend, to be coincident with 
conservative working and conditions 
in which the trees have manifested 
ability to produce good sustained 
yields. Hence the fact that the trees 
in Group 1 had by midseason nearly 
three times as many summerwood 
cells as those in Group 3 appears 
worthy of note. 
Examination at end of season.— 
On November 24, 1923, two weeks 
still exceeded by about 50 per cent by 
those of Group 1. On comparing the 
width of 1923 rings in each group with 
the width of those formed in 1922, it 
is seen (Table IV) that here also the 
Group 1 trees showed greater vigor of 
growth than those of Group 3. In 
Plate 2 are shown typical microscopic 
sections from chips from these groups. 
The tendency in Group 3 to produce 
narrower rings and fewer ducts is 
plainly evident, as is also the relative 
width of the 1922 and 1923 rings. 
At the left (PI. 2) are shown sections 
from the most vigorous trees in each 
group; at the right some from the 
poorest ones. On the average, Group 
1 produced growth rings almost 50 per 
cent wider than those of Group 3. 
Another difference between the trees 
of Groups 1 and 3 is significant. 
Certain of the wound-induced resin 
