UTILIZATION AND MANAGEMENT OF LODGEPOLE PINE. 
37 
Table 19. — Volume regulation for the next 140 years on the Bernice division, Deerlodge 
National Forest, Mont. 
Period. 
Stand 
matur- 
ing. 
Cutting 
each 
decade. 
Balance 
at end of 
decade. 
Present (1910) 
1,000 b. ft. 
92,831 
1,000 b. ft. 
20, 000 
20,000 
20, 000 
20,000 
20, 000 
20, 000 
20, 000 
20, 000 
20, 000 
20, 000 
70, 000 
70,000 
70, 000 
70, 000 
1,000 b. ft. 
72, 831 
Decade beginning — 
1920 
52, 831 
61,601 
1930 
1 28, 770 
1,254 
9,631 
6,628 
11,633 
12,215 
38,090 
15,058 
78, 920 
63, 448 
106, 730 
16,678 
1940 
42, 855 
1950 
32, 486 
I960 
19,114 
10,747 
1 970 
1980 
2,962 
1990 
21,052 
2000 
16,110 
2010 
25, 030 
18, 478 
55, 208 
2020 
2030 
2040 
1,886 
Total 
481,886 
480, 000 
1,886 
Average annual yield for rotation, 3,442 thousand board feet for the division, or 55 board feet per acre 
of productive timberland. 
1 Increment taking place on stands now merchantable, but which will not all be cut for about 50 years 
(65 board feet per acre added annually on 17,761 acres for 25 years). Sixty-five board feet per acre per 
annum is approximately the average increment in a stand 0.6 normal on an average site between the age 
of 120 and 160 years. 
It will be observed (Table 17) that a large proportion of the area 
is taken up with the younger age classes, due partly to heavy cuttings 
in the last 30 years. On the whole, however, the age classes are 
fairly well distributed for an unmanaged forest. It will also be seen 
(Table 18) that none of the older age classes have a high normality. 
This is because when such stands include over 2,000 board feet per 
acre they are classed with the merchantable timber, although they 
may be actually less than 120 years old. The method of volume 
regulation (Table 19) calls for a moderate cut on the division for 100 
years and a much heavier one for the last 40 years of the rotation, 
without reducing the annual cut at any time. Such a regulation is 
made necessary by the irregularity in the distribution of age classes. 
Other divisions of the Forest have a surplus of their area in the older 
age classes, so that the annual cut for the entire Forest and for the 
whole rotation can be given the proper degree of uniformity only by 
applying the regulation to groups of such divisions rather than to 
each division separately. The figures showing the stand maturing 
for each 10-year period are taken directly from Table 18, except the 
figures for 1930, which represent the approximate growth on the 
mature timber originally on the area. The figures for the real 
growing stock (present total stand) in Table 18 were obtained by 
multiplying the normal stand peracre for each age class, as given in 
Table 9, United States Department of Agriculture Bulletin 154, 
u The Life History of Lodgepole Pine in the Rocky Mountains," by 
the average normality (which gave the present stand per acre) and 
multiplying this result by the actual area occupied by each age class. 
For example, the normal yield on average sites at 10 years of age is 
