WHITE HNE UNDER FOREST MANAGEMENT. 
21 
The rate of growth of the stand is influenced by the same physical 
factors which control that of the individual tree. Computations of 
future yield must, therefore, take into account conditions under 
which the trees grow, and it is customary to classify stands accord- 
ing to their height growth, which, as previously said, is the best 
indicaton of the quality of the site. Quality I shows the most rapid 
growth, and quality III the slowest. 
Stands fully stocked, that is, those which contain just enough 
trees to utilize all the growing space and to produce well-formed 
trunks, are said to be "normal." Too many trees result hi slender- 
stemmed, slow-growing stands; too few do not fully utilize the 
growing space, and produce limby stands of relatively low value. 
Since growth is more rapid and competition more keen in good 
situations than in poor ones, the number of trees is less and their 
size greater in fully stocked quality I stands than in quality III 
stands of the same age and type. 
YIELD OF SECOND-GROWTH WHITE PINE. 
The yield of a stand, that is, the amount of wood produced per acre, 
in large measure determines the choice of species or of material to be 
produced, the length of rotation, and other important features of man- 
agement. Volume growth of a stand depends, of course, upon the 
height, diameter, and volume of the individual trees, and also upon 
the number of trees. 
Tables 3 to 6, which give the yield per acre of three qualities of 
second-growth white pine, are based upon the results of measure- 
ments of 196 typical fully stocked second-growth stands in New 
Hampshire, by C. A. Lyford and Louis Margolin of the Forest Serv- 
ice. 1 The tables are for use either as guides in predicting the future 
yield of young second-growth or for determining the present yield 
of existing stands. 
Table 3.- 
- Yield 
per acre in cub 
ic feet, 
quality I. 
Age. 
Aver- 
age 
height 
of domi- 
nant 
trees. 
Diam- 
eter 
breast 
high of 
average 
tree. 
Num- 
ber of 
trees 
per 
acre. 
Basal 
area 
per 
acre. 
Total j 
yield. 
Age. 
Aver- 
age 
height 
of domi- 
nant 
trees. 
Diam- 
eter 
breast 
high of 
average 
tree. 
Num- 
ber of 
trees 
per 
acre. 
Basal 
area 
per 
acre. 
Total 
yield. 
Years. 
10 
15 
20 
25 
30 
35 
40 
45 
50 
55 
Feet. 
7.2 
14.5 
24.5 
34.5 
44.0 
53.0 
61.0 
68.0 
74.5 
80.5 
Inches. 
1.7 
2.9 
4.0 
5.2 
6.4 
7.5 
8.6 
9.7 
10.8 
11.8 
1,728 
1,520 
1,322 
1,115 
879 
710 
583 
485 
408 
354 
Sq.ft. 
29 
68 
115 
162 
196 
218 
235 
249 
260 
269 
Cu.ft. 
800 
1,400 
2,100 
3,000 
4, ooo ; 
5,200 
6,500 
7,700 
8,800 
9,700 
Years. 
60 
65 
70 
75 
80 
85 
90 
95 
100 
Feet. 
85.5 
90.5 
94.5 
98.0 
101.5 
105.0 
108.0 
no. 5 
113.0 
Inches. 
12.8 
13.7 
14.7 
15.6 
16.5 
17.4 
18.2 
19.0 
19.8 
311 
279 
249 
226 
207 
190 
177 
165 
154 
Sq.ft. 
278 
286 
293 
300 
307 
313 
319 
324 
330 
Cu.ft. 
10, 500 
11,300 
11,900 
12, 500 
13,000 
13,500 
14, 000 
14, 400 
14, 700 
1 Tables based on these measurements have already been pubtished in the biennial reports of the For- 
estry Commission of New Hampshire for 1905-6 and 1907-8. The present tables differ from the others in 
that the separation into quality classes is made upon the basis of the height of the dominant trees instead 
Oithat of the yield itself. 
