36 BULLETIN" 55, U. S. DEPARTMENT OF AGRICULTURE. 
DIAMETER GROWTH. 
Balsam fir makes its most rapid growth in diameter between the 
ages of 25 and 70 years, during which time the average rate is about 
0.11 of an inch a year, or 1 inch in 9 years. On less favorable situa- 
tions it grows at the rate of about 1 inch in 10 years. After the sev- 
entieth year the diameter growth begins to decline, and at 75 years 
the current annual growth falls below the mean annual growth. 
Tables 13 and 14 give the growth of balsam fir in diameter on differ- 
ent stations in the Adirondacks . 
Table 13. — Diameter growth, in inches, of balsam fir in Xew York, on the basis of age. 
Age (years). 
Hardwood slope. 
(Based on 277 trees.) 
Flat. 
(Based on 246 trees.) 
(Base 
Swamp. 
i on 15S trees.) 
Diam- 
eter 
breast 
high. 
Growth 
in di- 
ameter 
every 
5 years. 
growth 
in di- 
ameter 
within 
5-vear 
period. 
Diam- 
eter 
breast 
high. 
Growth 
in di- 
ameter 
every 
5 years. 
\ nnn al 
-T. fill Lidl 
growth 
in di- 
ameter 
within 
5-vear 
period. 
Diam- 
eter 
breast 
nign. 
Growth 
in di- 
ameter 
5 years. 
-\rmu.al 
growth 
in di- 
ameter 
^-vear 
period. 
in 
0. 4 
_ - 
0. 4 
0.3 
15 
.8 
0.4 
0.08 
.8 
0.4 
0. 08 
.6 
0.3 
0.06 
20 
1.3 
.5 
.10 
1.2 
.08 
. 1.0 
.4 
.08 
25 
1.9 
.6 
.12 
1. 7 
.10 
1. 4 
.4 
.08 
30 
2.6 
.14 
2.3 
.12 
1.8 
.4 
.08 
35 
3.3 
.14 
2.9 
.12 
2.3 
. 5 
.10 
40 
4.0 
.14 
3.6 
. 14 
2.8 
. 5 
.10 
45 
4.7 
.14 
4.3 
.14 
3.3 
.5 
.10 
50 
5.4 
. 14 
4.9 
.12 
3.8 
. 5 
.10 
55 
6.0 
!6 
.12 
5. 5 
.12 
4.4 
.6 
.12 
60 . 
6.5 
. 5 
.10 
6.0 
.10 
4.9 
.5 
.10 
65 . 
7.0 
. 5 
.10 
6.5 
.10 
5.4 
.5 
.10 
70 
7.4 
.4 
.08 
6 9 
.08 
5.8 
.4 
.08 
75. . 
7. 8 
.4 
.08 
7.2 
.06 
6.1 
.3 
.06 
80.. 
8.2 
.4 
.08 
7. 5 
.06 
6.5 
.4 
.08 
85 
8.5 
.3 
.06 
7.8 
.06 
6.8 
.3 
.06 
90 . . 
8.9 
.4 
.08 
8.1 
.06 
7.1 
.3 
.06 
95 
9.2 
.3 
.06 
8.3 
.04 
7.4 
.3 
.06 
100 
9.5 
.06 
8.6 
.06 
7.6 
•2 
.04 
105 
9.8 
i 
.06 
8.9 
.06 
7.9 
.3 
.06 
110 
10.1 
.3 
.06 
9.1 
.04 
8.1 
.2 
.04 
115 
10.4 
.3 
.06 
9.4 
.06 
8.4 
.3 
.06 
120 
10. 7 
.3 
.06 
9.6 
.04 
8.6 
.2 
.04 
125 
11.0 
.3 
.06 
9.9 
.06 
8.8 
.2 
.04 
130 
11.3 
.3 
.06 
10.1 
.04 
9.1 
.3 
.06 
135 
11.6 
.3 
.06 
10.3 
.04 
9.3 
.2 
.04 
140 
11.9 
.3 
.06 
10.5 
.04 
9.5 
.2 
.04 
145 
12.2 
.3 
.06 
10.8 
.06 
9.8 
.3 
.06 
150 
12.5 
.3 
.06 
11.0 
.04 
10.0 
.2 
.04 
Table 14. — Number of years required by balsam fir in Xew York to grow 1 inch. 
Hardwood slope. 
Flat. 
Swamp. 
(Based on 277 trees.) 
(Based on 246 trees.) 
(Based on 158 trees.) 
Diameter breast high (inches). 
Years 
Years 
Years 
Age 
required 
Age 
required 
Age 
required 
(years). 
to grow 
(years). 
to grow 
(years). 
to grow 
1 inch. 
1 inch. 
1 inch. 
1 
17 
17 
18 
18 
20 
20 
2 
26 
9 
28 
10 
32 
12 
3 
33 
7 
36 
8 
42 
10 
4 
40 
7 
43 
7 
52 
10 
5 
47 
7 
51 
8 
61 
9 
6 
55 
8 
60 
9 
73 
12 
7 
65 
10 
72 
12 
89 
16 
8 
78 
13 
89 
108 
19 
9 
93 
15 
108 
11 
129 
21 
10 
108 
15 
128 
20 
150 
21 
11 
125 
17 
150 
22 
12 
142 
17 
