28 
BULLETIN 1291, U. S. DEPARTMENT OF AGRICULTURE 
Table 16. — Volume growth of aspen and associated conifers, inside of oark 
Cubic feet (entire tree) 
Age 
Aspen 
site 2 i 
Douglas 
fir 
White 
fir 
Alpine 
fir 
Engel- 
m.'inn 
spruce 
10 years .. - .. . ... . .". 
20 years __ 
0.1 
.3 
.9 
1.9 
3.0 
4.8 
6.5 
9.1 
11.5 
13.5 
14.8 
16.8 
18.4 
20.4 
0.5 
1.0 
1.6 
2.8 
4.5 
6.5 
8.8 
11.3 
14 1 
16.9 
19.8 
22.5 
25.5 
28.3 
31.7 
35.6 
40.5 
50 years . __ . ..... ... 
0.6 
1.1 
2.0 
3.4 
5.2 
7.4 
9.6 
12.1 
15.0 
17.7 
20.8 
24.3 
27.6 
31.4 
35.6 
40.9 
0.6 
1.1 
2.4 
5.0 
8.0 
12.0 
16.0 
19.8 
23.6 
27.6 
31.5 
35.5 
39.4 
43.2 
47.0 
51.0 
0.1 
70 years . . .. ... ... 
.2 
80 years .... --..-. ..-. ...... ... 
.6 
1.2 
100 vears . .. 
2.0 
110 vears . . . .. 
3.6 
120 years 
5.4 
130 years .. ... 
6.4 
9.8 
150 years . . ... 
12.5 
15.2 
18.0 
180 years 
21.4 
24.4 
30.5 
1 Prepared from Tables 14 and 15 with volume tables shown in Appendix. 
YIELD 
The yield per acre depends on the volume of the individual trees 
making up the stand and the number of trees per acre. In making 
a comparison between conifers and aspen, it is much easier to com- 
pare volumes of trees than numbers per acre, since aspen develops 
typically as an even-aged stand while conifers are more often uneven- 
aged. In the intermountain region, where coniferous stands are 
open and reproduction is not plentiful, these stands are more likely 
to be understocked than are the aspen areas. The Douglas-fir type, 
furthermore, has been heavily culled over and virgin stands are 
rare. The potentialities of this type under management are almost 
impossible to determine. 
The yield of aspen on sites 1 to 4 is shown in Table 17, and the 
mean annual increment per acre of aspen in different classes of 
products in Table 18. 
Table 17. — Empirical yield taole for even-aged aspen stands 
SITE 1 
Entire 
stand 
Main stand ! 
Age 
Trees 
per acre 
Trees 
per acre 
Average 
diameter 
breast 
high 
Basal 
area 
Volume per acre 2 
Total 3 
Cord- 
wood * 
Mine 
props 8 
Saw 
timber 6 
1,600 
1,300 
960 
750 
710 
1,000 
750 
610 
Inches 
Square 
feet 
76 
124 
136 
144 
Cubic 
feet 
300 
1,350 
2,250 
3,000 
Cubic 
feet 
Linear 
feet 
Board 
feet 
4.5 
5.3 
6.1 
850 
1,550 
2,200 
50 vears ... . . . 
3,400 
6,200 
600 
60 years 
2,600 
1 Trees more than 4 inches in diameter breast high. 
2 Gross volume without cull factor of any kind. 
3 Includes total volume of all trees more than 4 inches in diameter breast high. 
4 Includes total volume of all trees 6 inches diameter breast high and over, to a top-diameter limit of 5 
inches. 
8 Includes all trees 7 inches to 11 inches in diameter at breast height. Merchantable length taken to 5 
inches inside bark in tops. 
6 Includes all trees 10 inches and over diameter at breast height. Merchantable length taken to a 9-inch 
diameter limit in tops. 
