40 
BULLETIN 55, U. S. DEPARTMENT OF AGRICULTURE. 
that it begins to decline. On the flat the maximum rate of volume 
growth is reached at an age between 50 and 85 years, after which it 
slightly declines and remains stationary until a very old age. 
The increment in cubic feet becomes noticeable much later than 
the growth in height or diameter; namely, when the tree is 40 or 50 
years old. This is still more marked in the case of the increment in 
board feet. Thus, up to 70 years, even on the hardwood slope, where 
the growth is fastest, no increment in board feet is noticeable. It 
reaches its highest rate at the age of 125 years, and continues at a 
fairly steady rate practically to the limit of the physical life of the 
tree. On the flat the increment in board feet starts at about 80 and 
in the swamp at from 90 to 95 years. 
Table 19. — Total volume, in cubic feet, of balsam fir in New York, on the basis of diameter 
and height. 
Diameter breast high (inches;. 
Height of tree (feet). 
20 
30 
40 
50 
60 
70 
80 
Total volume (cubic feet). 
0.51 
.96 
1.48 
0.81 
1.43 
2.21 
3.15 
4.24 
1.91 
2.95 
4.19 
5.63 
7.25 
i 
3.60 
5.23 
7.01 
9.01 
11.19 
13.59 
16.10 
6 
6. 24 
8.37 
10.76 
13.38 
16.23 
19.25 
22.38 
25.71 
29.12 
32.77 
36.53 
7.24 
9.72 
12.51 
15.55 
18.86 
22.36 
26.06 
29.94 
33. 9S 
38.14 
42.52 
11.07 
14.24 
17.71 
21.47 
25.50 
29.72 
34.14 
38. 74 
43.59 
48.59 
10 
11 
12 
13 
14 : 
15 
16 
1 
Table 20. — Total volume, in cub ic feet, of balsam fir in Maine, on the basis of diameter 
and height. 
Diameter breast high (inches). 
Height of tree (feet). 
Total volume (cubic feet). 
80 
5.68 
7.20 
8.76 
10.34 
8 ". 
7.22 
9.17 
11.12 
13.22 
15. 33 
9 
8.87 
11.26 
13.75 
16.33 
18.98 
10.. 
13.20 
16. 49 
19.66 
22.91 
11 
15.77 
19.40 
22. 3S 
. 25.44 
28. 48 
31.52 
34.52 
23.15 
26.83 
30.58 
34.35 
38.14 
42.03 
27.03 
31.42 
35.91 
40.45 
45.06 
49.71 
12 
13 | 
14 
15 
16 
