THE RED SPRUCE. 
39 
136 1 board feet. A 16. 25-inch, tree similarly is 66 feet tall and has a 
volume (interpolated) of 188 board feet. Thus the increased growth 
during the 15 years is 52 board feet, equivalent to 38 per cent. 
When the future yield of whole stands is to be computed a tabular 
arrangement of such values will be found convenient. 2 
Inch 
Corre- 
Corresponding 
volume. 
Diameter. 
Corresponding volume value 
from (4). 1 
diameter 
sponding 
Direct 
from 
class. 
height. 
Values 
in (3) 
curved. 
10 vears 
20 years 
30 vears 
10 years 
20 years 
30 years 
volume 
table. 
hence. 
hence. 
hence. 
hence. 
hence. 
hence. 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Feet. 
Board ft. 
Board ft. 
Inches. 
Inches. 
Inches. 
Board ft. 
Board ft. 
Board ft. 
8 
47 
31 
31 
10.2 
12.5 
14.7 
61 
107 
162 
9 
50 
43 
43 
11.2 
13.4 
15.6 
77 
128 
188 
10 
53 
55 
58 
12.1 
14.2 
16.3 
97 
148 
209 
11 
56 
82 
75 
13.0 
14.9 
16.9 
118 
167 
227 
12 
58 
97 
95 
13.8 
15.7 
17.5 
138 
191 
245 
13 
60 
120 
118 
14.7 
16.4 
18.0 
162 
212 
260 
14 
62 
130 
143 
15.5 
17.0 
18.5 
185 
230 
278 
15 
64 
150 
170 
16.3 
17.6 
18.8 
209 
218 
288 
16 
66 
200 
200 
17.1 
18.2 
19.3 
233 
267 
306 
17 
68 
230 
230 
17.9 
18.9 
19.8 
257 
291 
324 
18 
70 
2C0 
2C0 
19 
71 
73 
290 
320 
295 
331 
20 
1 Interpolated. 
It will be noted that in column 3 the values have not been interpolated, although they might well have 
been. Instead they have been read directly from the volume table and the irregularities evened off in 
column 4 by curving. The values in columns 8, 9, and 10 are interpolated from column 4 in order to eliminate 
the irregularity that would otherwise result from rounding oft the diameter values in columns 5, 6, and 7 
and reading direct from column 4. Curving of the values in 8, 9, and 10 may in some instances be necessary. 
The figures contained in Tables 15 and 16 show the comparative 
development of spruce in the Adirondacks and West Virginia under 
" average maximum" growth conditions. Unfortunately, the data 
were msumcient upon which to extend the New York table above 120 
years. An inspection of the height and diameter tables upon which 
this is based, however, shows the growth of each very much slack- 
ened. Inspection of Table 15 itself shows that the periodic annual 
growth culminated in the ninetieth year, while the mean annual 
would unquestionably culminate under 150 years. In West Virginia, 
on the other hand, the periodic annual growth does not begin to 
slacken until the one hundred and fiftieth year, while the mean annual 
growth continues unabated until the two hundred and fiftieth year. 
i Under ordinary circumstances it would be sufficiently accurate to use the value corresponding to a 
14-inch tree 60 feet in height which, according to Table 29, is 130 board feet. In computations of this sort 
however, the volume table values had better be interpolated so as to secure a closer reading. Thus, it 
may be assumed that if a 14-inch tree has a volume of 130 board feet when 60 feet tall and 1G0 board fe?t 
when 70 feet tall, when it is 62 feet tall its volume will be 136 board feet (130 (160-130) by 0.2) . 
2 The tabular form indicates all the steps to be taken in making up such a table of values for red spruce in 
New York under "average maximum" growth conditions. 
