44 PRACTICAL FORESTRY IN THE ADIRONDACKS. 
GROWTH IN DIFFERENT PARTS OF A TREE. 
An exceedingly interesting question is the rate of growth of different 
parts of the same tree. It must be borne in mind that the material for 
growth is elaborated within the crown from material derived from the 
air and the roots, and that this elaborated sap comes down in the inside 
of the bark. It is not difficult to see that within the crown the rate of 
growth must be more rapid at the lower part than near the top, because 
each branch adds a certain amount of material for the growth below 
which the stem above did not have. In general, except close to the 
ground, the growth falls off below the crown. In the case of trees very 
much suppressed it may happen that not enough material for growth is 
formed in the crown to reach the lower part of the stem, and in some 
cases the number of annual rings on the stump will not represent accu- 
rately the age of the tree, because for some years there may have been 
no growth whatever in the lower part of the stem. This happens, how- 
ever, usually only in the case of dying trees. The width of the annual 
rings is smaller at the lower part of the stem than above, even if the 
same amount of material is brought down, because it has to extend 
over a larger surface. The results of the measurements taken on about 
2,000 Spruces show the largest growth in the crown, the smallest at the 
top of the first log, and a medium growth on the stump. Where the 
trees had an increased growth after thinning, the largest growth was 
at the stump. The fact that the increased growth at this part of the 
stem is out of proportion to that above has led some observers to believe 
that it is not necessary for all the food materials to be digested in the 
crown before they can be used in growth. This theory is the result 
of the phenomenon just mentioned, and of the fact that those roots 
of a tree which are in the richest soil grow to the largest size. In 
_ order to present more clearly the relation of the rate of growth at the 
different parts of the tree under the new influences of light and space 
after thinning, the following table has been made from 59 trees, all of 
which showed accelerated growth on the stump: 
Rate of growth at different sections of the stem. 
[From ‘‘The Adirondack Spruce.”’] 
. (Mean annual diameter growth.) 
/ he st D. ah f first log. Te f d log. 
Di i On the stump SEDER ENS SD AUIS, OE er ae ene ‘Number of 
lameter. | trees. 
| 1886-1888 | 1888-1896 | 1886-1888 | 1888-1896 | 1886-1888 | 1888-1896 | 
Inches. 
6 0.14 0. 20 0.12 0512 Jo 2sete tess A Eee ee 1 
7 105 24 12 . 14 0.15 0.16 12 
8 125 20 12 15 16 20 12 
9 11 20 Abt s12 14 16 15 
10 13 21 sal a6 15 22 10 
iti 105 17 10 11 12 16 5 
12 17 23 08 at 20 22 4 
Paes 12 21 AL 13" | 15 18 59 
Norr.—The above results make it clear that measurements taken at the top of the first or second 
log can not safely be used in reasoning about growth on the stump, or vice versa. 
