38 BULLETIN 1291, I T . S. DEPARTMENT OF AGRICULTURE 
Yield of aspen and conifers on saw-timber oasis. — The volume of 
conifers in board feet is usually about four times their volume in 
cubic feet, including the whole stem. This rough converting factor 
has been employed in estimating section B in Table 22, and the re- 
sultant figures here and in sections E and F make it clearly evident 
that, for saw timber, aspen can not compete with conifers, even when 
its large secondary grazing value is added and the greater value of 
conifers for watershed protection is disregarded. 
Yields of aspen and conifers on cordwood basis. — If in the future 
the paper industry should develop in this region to such an extent 
that both aspen and the associated conifers would be in demand for 
pulping, aspen would probably have a little advantage over the 
conifers in production of solid volume of wood, except on the poorest 
sites. Still, under management, conifers ought to grow more densely 
than they now do, giving better annual increment, while aspen ap- 
parently can not be very much improved in this regard by manage- 
ment. The monetary income from aspen, if it has a stumpage value 
equal to conifers for pulp, would slightly exceed the income from 
conifers, while the secondary income from grazing would increase 
this difference. This is shown in sections C, E, and F of Table 22. 
Aspen managed for cordicood and conifers for saw timber. — Com- 
parison of sections B and C of the same table will show roughly the 
relation between these two forms of utilization. On the better sites 
the gross income including that for grazing, is virtually equal, but 
on poorer sites the conifers have a greater value. Excluding forage 
value, conifers are superior on all sites. 
Yield of aspen and conifers for mine props. — Financial aspects 
of this form of management can not be gone into even in a rough 
way, on account of the entire lack of data on the yield of conifers 
under this form of management. The indications are that conifers 
would outstrip aspen in gross income from this form of production ; 
for although it takes longer for the individual conifer to reach prop 
size than it does aspen, conifer props are more valuable, and the 
conifers are much more adaptable than aspen to a system of cutting 
that removes only a portion of the stand (trees 7 to 10 inches in diam- 
eter breast high). The smaller, partly suppressed aspen, under these 
circumstances, grows crooked and responds poorly after the cutting; 
whereas the more tolerant conifers maintain a straight trunk and re- 
spond quickly to partial cuttings. 
Yield of conifer saw timber and aspen mine props. — It is possi- 
ble to estimate roughly the gross income from these two forms of 
utilization. Section D of Table 22 shows the results from the man- 
agement of aspen on a mine-prop basis. The mean annual increment 
at 80 to 90 j^ears in terms of mine props is 134 linear feet per acre 
per annum on site 1, 105 linear feet on site 2, 88 linear feet on site 
3, and 50 linear feet on site 4. In terms of money value, at a stump- 
age of 0.5 cent per linear foot, results are obtained as shown in 
Table 22. 
It is apparent that aspen would be capable of bringing in far more 
income from mine props than any other form of utilization, were 
it to command a certain market, and also that this income would 
considerably exceed the best that conifers can show. This is not 
due to better production of this class of material by aspen, but de- 
