BALSAM FIR, 
39 
the age of 70 years the annual growth of balsam fir declines, while that 
of spruce shows a gradual increase. After the age of 150 years spruce 
catches up with balsam fir, and finally surpasses it both in height and 
diameter. On the whole the rate of growth of balsam fir is more 
rapid during its entire life than that of spruce. The growth of 
spruce is, however, more persistent, and does not exhaust itself as 
early. It is this persistent growth and its long life which enable 
spruce to reach larger dimensions. 
This difference in growth is also apparent on cut-over land. Meas- 
urements in New Hampshire during 10 years following cutting gave 
the results shown in Table 18. 
Table 18. — Comparative growth in diameter of spruce and balsam on culled land in 
Grafton County, N. H. 
Diameter breast high at time 
of cutting (inches). 
Diameter breast 
high after 10 
years (inches). 
Diameter breast high at time 
of cutting (inches). 
Diameter breast 
high after 10 
years (inches). 
Spruce. 
Balsam. 
Spruce. 
Balsam. 
8 
8.82 
10. 00 
11.00 
12.00 
13.00 
14. 00 
9.56 
10. 60 
11.40 
12.34 
13.34 
14. 34 
14 
14. 64 
15. 64 
16. 64 
- 17. 64 
18.64 
9 
15.. 
10 
16 
17 
12 
18 : 
13 
Balsam fir up to 13 inches in diameter responded to increased light 
and space more vigorously than spruce, but did not go beyond the 
limit of 14 inches, while spruce continued to show a slower but a uni- 
form increase in growth of 1 inch for each 1 inch in diameter up to 18 
inches. 
VOLUME GROWTH. 
Tables 19 to 23 give the increment of balsam fir in cubic feet and 
board measure for the three different types in New York and in cubic 
feet for all types in Maine. The tables of volume growth, more than 
the tables of height and diameter growth, bring out the better devel- 
opment of balsam fir in Maine than in New York and other States. 
The annual increment in Maine is practically twice that in New York. 
Similarly, the volume-growth tables bring out more clearly the differ- 
ences in the increment of balsam fir in different situations. Thus, in 
the swamp the increment is less than in the flat or on the hardwood 
slope but is more persistent, illustrated by the fact that at the age of 
150 years it still continues at an increasing rate. In the swamp the 
growth of balsam fir resembles more nearly that of spruce. On the 
hardwood slope the volume growth of balsam fir shows the same tend- 
ency as that in height and diameter. It reaches its climax compara- 
tively early and is greatest between the ages of 80 and 95 years. After 
