ASPEN IN THE CENTRAL ROCKY MOUNTAIN REGION 
37 
tem probably 3,000 feet would be left after cutting, so that the aver- 
age stand during the cutting cycle would be 7,500 feet. The grazing 
income under such conditions would be 2.7 cents per acre. As sites 
become poorer conifer stands become more open in the aspen region, 
so that forage values tend to rise as site quality deteriorates. Figured 
as above, the values of forage would amount roughly to 3 cents an 
acre on site 2, 3.3 cents on site 3, 3.8 cents on site 4, and 4.5 cents 
on site 5. 
Another secondary and indirect value which differs in aspen and 
conifer stands is watershed protection. Conifers probably protect 
the soil against excessive erosion better than aspen, and they retard 
snow melting. The practical value lies mostly in the latter, however, 
for under proper forest management destructive erosion should never 
be found in either type. In the Douglas fir type the snow water is 
of little importance for direct irrigation, although it has great value 
for filling reservoirs. In the spruce-fir type the water stores are 
the largest, and as the snows melt last there they are the mainstay 
of irrigation. An even, prolonged flow is promoted by a conifer 
cover, which is distinctly more desirable than aspen. Owing to the 
lack of quantitative data regarding watershed protection and sus- 
tained run-off no monetary value can be assigned to this factor. 
The cost of management is probably somewhat less in aspen stands 
than in conifers on account of the clean-cutting method, which makes 
the marketing of individual trees unnecessary and lightens timber- 
sale supervision. The differences will be inconsiderable, especially 
when distributed over an entire rotation. 
Considering all the variations in primary and secondary monetary 
yields of the aspen and coniferous types, it is impossible to get more 
than a rough idea of how the types compare under different degrees 
of utilization. A rough comparison such as that shown in Table 22 
may be made. It will be indicative of general conditions. 
Table 22, 
-Gross annual income (cents per acre) from aspen and conifers com- 
pared under different forms of management 
Utilization 
Site 
A. Forage: 
Aspen 
Conifer 
B . Saw timber 1 : 
Aspen 
Conifer 
C. Cordwood 2 : 
Aspen 
Conifer 
D. Mine props: Aspen 
E. Total aspen yields: 
Saw timber -Horage 
Cordwood+forage.. 
Mine props+forage 
F. Total conifer yields: 
Saw timber+forage 
Cordwood+forage. . 
7.2 
2.7 
16.5 
29 
23.2 
21 
67 
23.7 
30.4 
74.2 
31.7 
23.7 
7.2 
3 
17 
13.9 
10.6 
52.5 
16.5 
21.1 
57.7 
20 
13.6 
7.2 
3.3 
2.7 
12 
8.5 
6.1 
44 
15.7 
51.2 
15.3 
9.3 
7.2 
3.8 
.4 
11.2 
6.1 
5.2 
25 
7.6 
13.2 
32.2 
15 
9 
7.2 
4.5 
7.2 
'I.~5 
7.2 
7.2 
7.2 
11.7 
7 
1 Aspen $1.80 per thousand; mixed conifers $2 per thousand stumpage. 
1 Values in Table 19 reduced 7 cubic feet per acre to approximate cubic feet on a 5-inch limit (pulp- 
wood) . Stumpage $0.75 per cord for both aspen and conifers. 
