192 
Indian Forest Records. 
rvoL. I. 
PART III. 
STEM (TIMBER, FIREWOOD, AND MERCHANTABLE TIMBER) ; 
CROWN: BARK: ROOTS. 
Section 1, — Preliminary Matters. 
A Sal tree consists of a crown, root and stem. The stem is the most 
important part of the tree, and the available statistical data relating to 
the progress of its growth in volume have already been dealt with in Part 
11. From a commercial point of view, however, a stem may be said to 
consist of timber or merchantable timber (wood above a certain mini- 
mum girth), and firewood (small wood below a certain girth). The 
development of the timber and the firewood of a stem and the propor- 
tion which each of these, as well as the roots and crown, bear to the total 
volume of the stem is of importance in forest management ; and data 
dealing with these points have in recent years been collected and 
published by the several Forest Research Bureaux of Europe. 
Section 2.— The Development of the Timber, Merchantable 
Timber, and Firewood in Stem. 
Laws ivliicli govern development of timber and firewood in general : — 
I. For a single tree, the proportion between the volume of firewood and the 
total volume of the stem continues to diminish rapidly in early youth 
■with every increase in diameter until it becomes constant. 
II. For trees of equal diameter, the taller the tree, the smaller the propor- 
tion of firewood. 
III. For trees of equal height, the jiroportion of firewood inci’eases slightly 
with the diameter. 
IV. Trees grown in very open woods produce a proportionately larger quan- 
tity of small wood than those groum in close crops. 
V. In a whole wood, the volume of the small wood during early youth increases 
rapidly year by year ; it soon, however, reaches a maximum ; then 
diminishes slightly for some years until it eventually remains con- 
stant. 
VI. The current and the mean aimual volume increment of the timber alone 
in a tree or wood culminates at a much later date than that of the 
whole tree or wood. 
VII. The greater the girth dimension of the timber, the later will the volume in- 
crement culminate, and the higher will have to be the rotation of the 
greatest production of volume. 
VIII. The volume increment per cent, for the timber alone of a tree or wood is 
higher than that calculated for the whole tree or wood at any given 
age : but the difference continually decreases as the tree increases in 
age. 
