Dec. is, 1925 Yield Capacities of Yellow Pine Type in California 1125 
yellow pine on the east slope the shortest timber is about 70 to 80 
ieet high, and the tallest about 170 feet, though very rarely stands 
nearly 200 feet high are encountered. On the particular area studied 
there are several fairly definite mature heights. Near the west 
side of Eagle Lake, for example, there is a large body of timber 
about 80 feet in height. On the easterly slopes in the same region, 
stands of 100 feet are found, and in the vicinity of Bogard Flat 
and on most of the buttes on the area, 120 feet is the common 
height of the virgin stand. The values finally selected therefore are: 
Site 1, over 150 feet; site 2, from 131 to 150 feet; site 3, from 111 to 
130 feet; site 4, from 91 to 110 feet; site 5, from 71 to 90 feet. It is 
immaterial for this study whether this classification is the one finally 
determined upon for the region or whether it meets with the general 
approval of the profession; the data are such that any other better 
definition can be readily accepted, and the data tied in with it. 
In accordance with this plan of site classification, tlja individual 
plots were sorted by age, 10-year age classes being used, and by site 
quality (Table I). The following data were computed for each indi¬ 
vidual plot and later plotted and curved on the basis of age classes: 
(1) Basal area per acre; (2) height of dominant trees; (3) diameter 
growth of dominant, intermediate, and suppressed trees; (4) trees 
per acre; (5) volume in board feet per acre; (6) volume in cubic feet 
per acre (Table II). 
Table I. — Distribution of plots in east slope yellow pine type by age and site ° 
Table II. — Yield of pure yellow pine, Lassen National Forest, Calif. 
[Clark International rule, K-inch kerf; values curved] 
SITE 1« 
Total 
age b 
(years) 
Number 
of trees 
per 
acre 
Basal 
area 
per 
acre 
Height 
of domi¬ 
nant 
Average 
diameter 
at breast 
height 
Volume per acre 
Periodic 
annual 
growth 
Mean 
annual 
growth 
Board- 
feet per 
cubic 
foot 
60_ 
356 
Sq.ft. 
168 
Feet 
53.0 
Inches 
9.3 
M. bd.ft. 
3.5 
Cu.ft. 
2,320 
M. bd.ft. 
0.35 
M. bd.ft. 
0.06 
1.51 
70.. 
251 
197 
64.0 
12.0 
13.5 
4,300 
1.00 
.19 
3.14 
80_ 
202 
225 
75.0 
14.3 
27.5 
6,480 
1.40 
.34 
4.24 
90_ 
174 
252 
86.0 
16.3 
43.5 
8,500 
1.60 
.48 
5.12 
100_ 
158 
276 
95.0 
17.9 
58.5 
10,250 
1.50 
.58 
5.71 
110_ 
146 
297 
103.0 
19.3 
67.5 
11,680 
.90 
.61 
5. 78 
120_.. 
138 
314 
109.0 
20.4 
74.0 
12,800 
.65 
.62 
5. 78 
130_ 
134 
328 
113.5 
21.2 
79.0 
13,650 
.50 
.61 
5. 79 
140_ 
133 
342 
117.0 
21.7 
83.0 
14,350 
.40 
.59 
5. 78 
150__.. 
132 
353 
120.5 
22.1 
86.8 
14,950 
.38 
.58 
5.81 
a Mature heights, 151+ feet; yellow pine 80+ per cent; basis, 8 plots. 
b Age at breast height is 20 years less than total age. 
