26 
BULLETIN 139, U. S. DEPARTMENT OF AGRICULTURE. 
diameter takes on the average Norway pine soil from 132 to 173 
years. The average annual growth culminates at about 140 years on 
all sites, and consequently the rotation which would give the greatest 
volume production would be one of 140 years. If timber is cut when 
too young or too old the full productive capacity of the soil is not 
utilized, especially if the timber is cut clear. When natural repro- 
duction is sought, particularly with the shelterwood system or from 
clear cutting, the stand should be felled if possible while the trees are 
producing seed prolificacy, i. e., between 80 and 130 years. 
Financial returns. — A long rotation means a larger growing stock 
or forest capital; and in compound interest calculations the interest 
on this standing timber more than counterbalances the sale value 
of the additional lumber produced. To illustrate this principle, 
according to Table 11 a Norway pine stand on Quality II soil 1 yields 
10,200 board feet after 60 years, 18,600 after 80, 27,400 after 100, and 
36,700 after. 120 years. Table 16 shows the estimated returns on 
money invested in Norway pine stands when cut after 60, 80, 100, and 
120 years. Compound interest has been figured at 4 per cent on an 
initial cost of $15 for land and young growth; taxes and fire protection 
at 4 cents per acre per year; and stumpage at $20, a very conservative 
figure, for the years 1973, 1993, and 2017. 
Table 16. — Revenue derived from the conservative management of Norway pine. 
Length 
rotation 
(years). 
Yield from thinnings. 
Final yield 
per acre. 
S15 capital 
at 4 per cent 
compound 
interest. 
Approxima- 
tion of final 
yield per 
cent on orig- 
inal invest- 
ment. 
60 
80 
100 
120 
[Estimated thirinings will pay cost of taxes and fire 
| protection 
f S204. 00 
J 372. 00 
1 548.00 
I 734.00 
S157. 79 
345. 74 
757. 57 
1,659.94 
44- 
4 + 
3H- 
31 
Any forecast of future returns necessarily involves some elements 
of uncertainty. What will be the taxes, fire loss, or unforeseen 
injuries? Will natural reproduction be wholly or partially success- 
ful, or a total failure ? What will be the stumpage price ? At what 
figure should the land and timber be capitalized ? It is certain that 
in 1950 Norway pine in the United States will bring at least as high 
a stumpage price as good Scotch pine in France and Germany brings 
now — from $12 to $24 per thousand board feet — probably 30 to 100 
per cent more, since it now nets from $10 to $12 on the stump. But 
even with such an increase, the returns from forest investments ex- 
tending over long periods of time are certain to be small as com- 
pared with returns from short-term investments. 
1 All calculations are based on Norway pine growing on sandy sail, because this is the soil to which the tree 
is naturally adapted. 
