THE EASTERN HEMLOCK. 
25 
Local variations in growth are also caused by climate and the 
quality, depth, drainage, and moisture of the soil. Growth is most 
rapid on the best soils. Hemlock is especially favored by a temper- 
ate, humid climate and long growing season, combined with moist 
but well-drained soils — conditions which it finds in the coves and 
slopes of the southern Appalachians. 
Tables 8 to 1 1 show the growth of hemlock in localities in various 
parts of its range. The tables give the maximum, minimum, and 
average rates of growth in height, diameter, and volume, and are 
based on measurements of many forest-grown trees differing widely 
in amount of suppression. Though not based on crown-class dis- 
tinctions, the maximum figures may safely be regarded as represent- 
ing the average growth of dominant trees on good soil, and the mini- 
mum that of suppressed trees which have reached merchantable 
size. The average figures, however, may represent the growth both 
of trees of the middle crown classes and of dominant trees in situa- 
tions of poor quality. These data were averaged separately for 
diameters, heights, and volumes, so that only an approximate 
relation exists between the values for any given age. Furthermore, 
the variation in height and volume among trees of a given diameter 
is considerable, as shown by the volume tables in the Appendix. 
Table 8. — Growth of hemlock in Leelanau County, Mich} 
Age. 
Diameter, breast-high. 
Height. 
Volume. 
Inches. 
Feet. 
Cubic feet. 
Board feet. 
Mini- 
mum. 
Aver- 
age. 
Maxi- 
mum. 
Mini- 
mum. 
Aver- 
age. 
Maxi- 
mum. 
Mini- 
mum. 
Aver- 
age. 
Maxi- 
mum. 
Aver- 
age. 
Maxi- 
mum. 
Years. 
20 
30 
40 
50 
60 
70 
80 
90 
100 
110 
120 
130 
140 
150 
160 
170 
180 
190 
200 
0.3 
.6 
.9 
1.3 
1.6 
2.0 
2.4 
2.7 
3.1 
3.4 
3.8 
4.3 
4.8 
5.3 
5.9 
6.6 
7.3 
8.0 
8.7 
0.7 
1.3 
2.1 
2.9 
3.8 
4.7 
5.7 
6.7 
7.8 
9.0 
10.0 
11.2 
12.3 
13.4 
14.5 
15.5 
16.5 
17.5 
18.4 
2.0 
3.9 
5.7 
7.6 
9.4 
11.1 
12.8 
14.5 
16.1 
17.7 
19.4 
21.0 
22.6 
24.2 
25.7 
27.2 
6 
7 
8 
10 
11 
13 
14 
15 
17 
18 
20 
21 
23 
25 
27 
29 
31 
33 
35 
8 
12 
16 
20 
25 
30 
35 
40 
44 
49 
53 
57 
60 
63 
66 
68 
70 
72 
74 
18 
31 
42 
53 
62 
70 
76 
82 
85 
88 
91 
94 
96 
98 
100 
102 
2.2 
6.6 
12.4 
20.0 
29.0 
39.0 
50.0 
64.0 
78.0 
94.0 
112.0 
131.0 
152.0 
174.0 
..... 
20 
35 
50 
67 
86 
110 
130 
150 
180 
210 
13 
31 
56 
80 
130 
180 
240 
320 
410 
500 
600 
700 
810 
910 
1,020 
1,130 
""i.'o" 
1.8 
2.6 
3.4 
4.6 
5.9 
1.8 
3.6 
5.9 
9.2 
12.5 
17.1 
22.0 
28.0 
34.0 
40.0 
47.0 
54.0 
61.0 
Based on measurements of 186 trees, 109 to 325 years old, made by S. J. Record in 1905. 
