On the Management of Turpentine Forests by Austin Cary, U.S. Forest Service, January 15, 1930 (3 pages)


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On the Management of Turpentine Forests by Austin Cary, U.S. Forest Service, January 15, 1930 (3 pages)
Series Title:
Folder 9
Physical Description:
Mixed Material
Cary, Austin, 1865-1936
Publication Date:
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Box: 1
Folder: Folder 9


Spatial Coverage:
North America -- United States of America

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Source Institution:
University of Florida
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All applicable rights reserved by the source institution and holding location.
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Full Text

SJanuary 15, 1930.

by Austin Cary, U. S. Forest Service

First Paper

The term "management" in connection with forest
growth has in some quarters a strict and technical meaning.
Most readers will not care for that, however but simply
look for something of utility to them that the name fairly
indicates. It is the intention to put out at this time a
few brief papers that may fill those specifications.
Thinning will be taken up to begin with. It is a timely
topie because a good maay men in the turpentine belt are
already practicing it on a considerable seale; then for some
years past it has been made the subject of rather close study
and of some experimenting.
Men want to know in the first plaee why they should
thin timber, a process that necessarily eosts more or less.
Answer to that question is easy indeed up to a certain point.
We have the analogy with agricultural crops for one thing;
everyone knows that without the additional outlay involved
in properly thinning the plants in a cotton or vegetable-crop
the work involved in plowing and sowing is poorly rewarded.
It is the same way with a timber crop, or may be. Longleaf
and slash pine both are trees characterized by occasional
very heavy masts; consequently they often gow up so dense
that only slim poles are produced and the date at which timber
may be profitably worked is set very far forward.

The following notes illustrate this. Early in
the winter of 1928-29, a parwy of men interested in the
questions involved, attracted by a grove of slash pine near
the highway between Wayoross and Folkston, stopped for a
while, ran out two plots 52 x 52 feet or 1/16 aore eaeh,
and calipered the trees upon them. The grove was at a very
interesting age and size 20 years old with total height of
good trees around 50 feet. One area was as densely looked
as could readily be found; the other desirably as it was
thought, or as near that as is often found in nature. Fol-
lowing are the results of the tally of trees on the two
areas given on the acre basis:

Diameter Desirable Stooking Dense Stooking
Breast High No. of trees No. of trees
2 inches 128
3 576
4 32 528
5 16 192
6 32 128
7 64 -3
8 64 16
9 is8
10 52
11 16
Total 8"T 1609

One prastieal inference may be immediately drawn,
one that will appeal to every turpentine operator. Kere is
a typical slash pine grove en good soil, 20 years old. Of
trees 9 inches in breast diameter and up (the Atandard set
by a good many men for profitable turpentining) there was
not & single one on the tense area; at the rate of 116 per
aere on that stooket desirable. Setea-inoh trees similarly
are the standard of working of a good many, and of that eise
there were 48 on the one traet, 304 on the other. These
last figures are at the rate of 6 1/3 to 1. As a matter of
fast ouap were haun on this bode of timber later ia the
winter, to abeot te standard of ise last mentioned.
It requires no more than that perhaps to eonvinee
a thinking man that thinning young turpentine timber at the
proper time and to the right density must pay. There are,
however, a good many side issues and teehnieal points eoa-
nectes with the matter, and some of these mar be inquired
into profitably.
how long does this eroding persist for one thing?
To what lengths will it go? Will certain trees those at
some natural advantage, break away from the resi after a
time, sheot ahead of and suppress them, and grow at a
generous rate thereafter? Those questions can be answered
with more precision when teohnioal men hate devoted further
time to them; meanwhile a provisional answer can be given
based on general but careful observation. It ean in fast
be said with confidence that this detrimental orowding
persists for a long period. A stand of slash pine was
gbeoende last winter still erowela at 40 years of b se,
8 nchee In breath diameter oe ntoutest tsee, in sore bunches,
and from that all the way down to 3 inches. Some years ago
such a stand was observed that was still older. About 60
faces was the number that had been worked to the aere up to
the date of observation, and the owner and observer agreed


that its condition was such that it better not be looked to
for further turpentine yield, that the best thing to do with
that particular piece of ground would be to out the stuff
off lean and let it oome up to a new erop which one might
hope would be handled better. As for longleaf, the power of
persistence under severe crowding is perhaps greater than for
slash. Men have before now been greatly deceived by it con-
eluding that 150 years was necessary to produce trees of kaww
log sise whereas a third of the time, with better spacing or
under management, would be quite sufficient.
The relative amounts of wood produced and the effect
of crowding on height growth are other points that may be made
the subject of profitable inquiry. This is one inference from
prolonged and careful study applied not only to the species of
trees concerned but to others that rate of height growth is
not mush affected by density between pretty wide limits; that
is to say only an entirely open and bushy tree is likely to be
abnormally short, while in crowded stands the same thing
happens only when trees have been overtopped and crowded under.
This idea, it is well understood, runs counter to general im-
pression, but it is well established and in fact develops a
relation that is of great value in the systematic study of the
growth of timber. Height growth is uniform, dependable, a re-
sultant of soil and climatic factors, a readily attainable
measure therefore of the producing power of a locality.
It is quite otherwise with the diameter of trees; the
growing spaee of eash, or in other words the number per acre,
tells the story. But if that is true for the single tree the
greater number may make compensation. That oomes out in lact
from examination of relations between the two areas above tallied.

Volume of wood produced is one test that might be
applied, and in raising timber for purposes in connection
with which the size of individual sticks does not count it
is the final and most important factor. For the present pur-
pose it seems Just as well to compare the plots by another
element easier'to get at, the number of square feet in the
breast high section of all the trees standing on an aore,
"basal area" the term foresters have applied to it*
Figured this way the dense stand of the two dis-
played above shows a basal area of 135 square feet per oare;
the other 142. Such difference as there is is in favor of
the open stand therefore, but being only a little more than
5 per cent it may be looked on as accidental. As far as we
have now gone therefore no difference in wood producing
power due to density of stocking appears, but what a dif-
ferenoe on the other hand in the utility and value of that