92 
Journal of Agricultural Research 
Vol. XXX, NO. 1 
chipped so deeply that they were dry¬ 
ing and soaking unduly. Such trees 
would obviously not present fair 
material from which to determine the 
effect of height of chipping. 
Good production has been obtained 
with the 3^-inch-deep and J^-inch- 
high streak on the by no means su¬ 
perior timber of the Florida National 
Forest. 12 The question then naturally 
arises whether or not it is possible to 
reduce still further the height of the 
layer of wood removed weekly. Ob¬ 
servations indicate that an eighth of 
an inch, a mere shaving of the surface, 
will not produce the effects desired; 
it can not be depended upon to remove 
the gum-soaked and abnormal surface 
tissue. In all cases, however, where 
good average 34-inch-high chipping of 
a safe depth has been used, reasonably 
satisfactory results have been obtained. 
In view, therefore, of the many indi¬ 
cations of good results of conservative 
chipping in general, and in view of the 
particular results of this test, it seems 
safe to work toward chipping lower 
faces. 
The lessened damage to the timber 
of such turpentining practice is a 
matter that can not fail to appeal to 
the owner of the forest and to the saw¬ 
mill interests. Even the chipper, ex¬ 
perience proves, once he has found that 
it is possible to take off less wood, 
readily falls into line. To be sure, he 
is somewhat averse to the longer 
period during which he must stoop to 
perform chipping low on the butt of 
the tree, but he is, on the other hand, 
spared much longer the hard work of 
pulling. The expenses of cup raising 
could be somewhat reduced by cutting 
lower faces. This is an item worth 
considering, as is the saving in spirits 
due to the fact that the gum does not 
have to go so far to reach the cup. 
Furthermore, turpentine camps might 
not need to be moved so frequently. 
If results continue to demonstrate the 
fundamental scientific soundness of 
the principle as well as its numerous 
practical advantages, the argument 
in favor of lower faces for commercial 
production would seem conclusive. 
At first, perhaps, No. I or No. 0 
hacks should be used to remove the 
commercially successful and thoroughly 
tested 3^-mch-high chips, and the 
streak then gradually reduced to as 
nearly J^-inch-high chipping as may 
be practicable. 
For 1924 it is planned to test low 
chipping at Cogdell, Ga.; Lockhart, 
Ala.; Holopaw, Opal, Starke, and 
Camp Pinchot, Fla.; and at several 
points in Mississippi and Louisiana 
SUMMARY OF RESULTS 
Evidence obtained from preliminary 
tests, notably the carefully conducted 
though comparatively small one here 
described, and from practical experi¬ 
ence indicates that many advantages 
(reduced scar, less lumber degrade, 
longer possible operation, higher sus¬ 
tained yield, and conservation of tree 
energy) may be gained by cutting 
comparatively low faces (10 inches to 
16 inches yearly at most). Such cutting 
has been satisfactorily accomplished by 
using a No. “0” hack. 
In the test described, three carefully 
matched groups of 20 trees each were 
chipped to the same depth (34 inch) 
and to a height of approximately 34 
inch for Group 1, J4 inch for Group 
and inch for Group 3. The Group 
1 trees (actual average height of chip 
0.28 inch) produced a higher total 
yield of gum during the first year of 
the test (1923) than was obtained from 
the trees of Groups 2 and 3 >vith higher 
faces. 
The trees with low faces showed 
earlier and more abundant wood for¬ 
mation (especially summerwood) and 
a greater amount of gum-yielding 
tissue (resin passages) than the trees 
with the higher faces. By midseason 
(July) they showed nearly twice as 
many wood cells (including about 
three times as much summerwood) 
and about twice as many resin pas¬ 
sages formed and ready to function as 
did the Group 3 trees which were 
chipped inch high each week. This 
would indicate better sustained vitality 
in the low-chipped trees, and hence 
would explain the higher producing 
power which was manifested in their 
yields. 
Preventable waste is caused by high 
chipping, since it removes more than is 
necessary of the rich gum-bearing 
tissue before it has had time to produce 
the yield of which it is capable. Micro¬ 
scopic study of the number and loca¬ 
tion in the ring of the resin passages 
at different heights in the face demon¬ 
strated that the early-formed, com¬ 
paratively short wound ducts are 
quickly cut away by high chipping. 
Low chipping permits the longest 
maximum production in any year, 
since the face is cut in the region 
richest in resin passages. Low chip¬ 
ping also makes it possible to hold 
over a reserve of this tissue to augment 
12 McKee, E. R. naval stores production on the Florida national forest. Naval Stores Rev. 
33 (6): 16-17; (7) 6, 23; (8) 6, 19; (9) 10, 23; (10) 16-17. 1923. 
