SUGAB PINE, oF 
figures represent roughly the results under a still greater degree of 
light or soil suppression. 
it appears from the diameter-growth table that the maximum cur- 
rent diameter growth occurs between 80 and 100 years, which is also 
the period of maximum height growth. The maximum average 
annual growth for this 20-year period is 0.37 inch. The rate of growth 
in diameter decreases less rapidly, however, than the rate of height 
growth, the current annua! exceeding the mean annual growth up 
to about the hundred and forty-fifth year. Usually the height 
erowth of a tree species culminates before the diameter growth. 
Whether the sustained rate of height growth apparent in this species 
is attributable to the fact that the trees measured grew in virgin 
forest, where their light requirements were not satisfied during youth, 
or whether this is an inherent peculiarity, has not yet been fully 
determined, and can not be until older, more normal second-growth 
stands are available for study. 3 
VOLUME GROWTH. 
Table 18, showing the growth in volume of sugar pine, is derived 
from tables of average growth in diameter and height at various ages 
and a volume table for trees of various diameters and heights (see 
p. 37-38, Appendix). The striking feature shown by this table is the 
great age to which the tree sustains volume production. The current 
annual volume growth remains above the mean annual growth for 
over 400 years, over 300 years after height and diameter growth have 
culminated. At 100 years of age the annual rate of volume growth is 
2 cubic feet. It then increases steadily up to an annual rate of 54 
cubic feet at 350 years. The rate of volume growth remains prac- 
tically constant from that age up to 460 years. No information to 
indicate its behavior at a greater age has been collected. 
TABLE 18.—Growth in voiume, on the basis of age, diameter, and height of average domi- 
nant trees, California Sierras. 
Average. | Volume. Average. | Volume. | 
x : arnt 
Diameter | F Board Diameter : Board | 
Age. outside Total raul feet Age. outside Total eubig feet 
bark at | yoj nt. | outside | Cchbner bark at | | Ns he eet | (Scribner 
breast Sle ae Decimal breast Rese eee Decimal 
height. il Crale: height. | seeatapeiines ine Os ile) | 
A SEAT NON gLE | 
Years Inches Feet Years. Inches Fect. | 
20 he) A Keres aa cee Se 220 40.0 148 | 530 2, 830 
40 22,5; PR a see CL aan Se MO evade 240 42.5 153 630 3, 460 
60 Hed A yi |e rap us sil ri aS cc cca 260 44,9 158 733 4,120 
80 1BeO 72 31 110 280 ee 162 &38 4,849 
100 18. 1 92 71 240 300 49,3 167 $44 5, 570 
120 PEAT 106 126 490 320 14 171i 1,050 6, 029 
140 26.8 118 192 850 349 Dd 0 174 1,158 invou 
169 30.5 127 268 1, 290 360 Ho 177 1,270 7, 740 
180 33.9 135 348 1,760 380 57.3 180 1,280 8, 280 
200 37.0 142 435 2, 250 400 59.1 | 183 1,488 9,C10 
