TIMBER GROWING IN THE LODGEPOLE PINE REGION 25 
Table 2. — Table of volume growth for Engelmami spruce 
Diameter, breast high, inches 
Rings per outside 
inch of radius re- 
quired to produce 
increment equal 
to— 
Diameter, breast high, inches 
Rings per outside 
inch of radius re- 
quired to produce 
increment equal 
to— 
5 board 1 cubic 
feet per i foot per 
year year 
5 board 
feet per 
year 
1 cubic 
foot per 
year 
6 
Number Number 
20 
Number 
20 
24 
27 
30 
33 
36 
40 
Number 
17 
8. 
3 
6 
10 
13 
15 
16 
22 
19 
10. 
4 
7 
11 
14 
17 
24 
21 
12. 
26 
23 
14 
28 
25 
16. 
30 
28 
18. 
32 
30 
Table 2 brings out the importance of studying carefully the indi- 
vidual tree before deciding which tree it is desirable to retain in the 
stand. It shows the number of annual rings to an outside inch of 
diameter required to maintain a uniform increment. In order to 
determine for any species whether a tree of a given diameter is 
still maintaining a uniform rate of increment, it will merely be 
necessary to see whether the ratio of the number of rings in the out- 
side inch to the number in the preceding inch is approximately the 
same as that of corresponding counts shown in Table 2. Board- foot 
volume is usually the more important indicator of the value of each 
tree. Table 2 shows that in cubic feet (applicable for pulp wood) 
trees are putting on relatively less volume in the larger sizes. This 
emphasizes the fact that the actual cubic-foot volume of trees does 
not increase so rapidly with size as board-foot volume does. 
In so large a region, with such greatly varying conditions, it is 
impossible to prescribe a method of selecting mature trees that is 
universally applicable. Each stand of timber is a problem in itself 
and requires special consideration and skill on the part of the person 
selecting trees for cutting. If the desired results are to be obtained, 
each tree must be examined closely, and conclusions based on external 
appearances must be checked by an examination of annual growth 
rings sufficient to insure the proper basis for selection. The last few 
rings may be examined without serious damage by chipping the tree, 
or an increment borer may be used to advantage. 
DEGREE OF CUTTING 
Methods of cutting and degree of cutting are of extreme im- 
portance in their effect upon satisfactory growth and a stabilized 
output. Except where stands are overmature, very heavy cutting 
or clear cutting results in loss of increment during the period of re- 
production and makes sustained production from a given manage- 
ment unit more difficult. Furthermore, such practice, even though 
it may be warranted by the condition of the stand, can be followed 
only where market conditions are very favorable. A larger pro- 
portion of desirable and valuable products are obtained from the 
larger trees. This is an important consideration in view of the pre- 
