THE EASTERN HEMLOCK. 
Table 10. — Growth of hemlock in Otsego County, N. Y. 1 
27 
Age. 
Diameter broast-high. 
Height. 
Volume. 
Inches. 
Feet. 
Cubic feet. 
Board feet. 
Mini- 
mum. 
Aver- 
age. 
Maxi- 
mum. 
Mini- 
mum. 
Aver- 
age. 
Maxi- 
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 
"■"6.T 
.3 
.5 
.7 
.9 
1.1 
1.3 
1.5 
1.9 
2.1 
2.4 
2.7 
3.0 
3.3 
3.7 
4.1 
4.4 
4.9 
0.4 
.9 
1.4 
1.9 
2.5 
3.3 
4.0 
4.7 
5.5 
6.4 
7.3 
8.3 
9.4 
10.5 
11.6 
12.7 
13.5 
14.3 
15.1 
1.5 
2.9 
4.4 
5.9 
7.4 
8.9 
10.5 
12.1 
13.8 
15.4 
17.1 
18.7 
20.4 
22.1 
23.9 
25.7 
27.4 
29.1 
30.9 
5' 
6 
7 
8 
9 
10 
11 
13 
15 
16 
17 
19 
20 
22 
23 
25 
27 
29 
7 
10 
13 
16 
20 
24 
28 
32 
36 
40 
45 
50 
54 
59 
63 
66 
69 
71 
72 
17 
28 
39 
49 
58 
66 
73 
79 
84 
88 
91 
94 
97 
100 
102 
105 

------ 
3.1 
5.0 
7.9 
11.1 
15.5 
20.0 
24.0 
29.0 
34.0 
39.0 
2.8 
6.4 
11.4 
18.1 
26.0 
36.0 
47.0 
60.0 
75.0 
91.0 
108.0 
126.0 
145.0 
""ie' 
29 
44 
61 
80 
100 
•120 
140 
30 
55 
86 
120 
170 
230 
300 
380 
480 
590 
710 
850 
1,000 
1,150 
Based on measurements of 176 trees, 48 to 420 years old, made by J. G. Peters in 1902. 
Table 11. — Growth of hemlock in Vermont. 2 
(Average.) 
Age. 
Diameter 
breast-high. 
Volume. 
Years. 
130 
140 
150 
160 
170 
180 
190 
200 
Inches. 
7.0 
8.0 
9.0 
10.2 
11.4 
12.6 
13.9 
15.2 
Bd.ft. 
34 
48 
69 
100 
140 
180 
230 
2 Data contained in Vermont Experiment Station Bulletin 161, "Hemlock in Vermont," by A. F. Hawes. 
Volumes scaled by Vermont rule. 
SUSCEPTIBILITY TO INJURY. 
As before stated, hemlock is extremely sensitive to sudden changes 
in the density of the forest. Middle-aged and full-grown trees appear 
to be the most susceptible. 
The most destructive of the insect enemies of hemlock is the flat- 
headed eastern hemlock bark borer, MelanopJiila fulvoguttata Harr. 
According to Mr. H. E. Burke 3 this insect "has caused the death of 
3 "Injuries to forest trees by flat-headed borers." Yearbook of the Department of Agriculture, 1909; 
pp. 405-406. See also following articles by Dr. A. D. Hopkins: 
"Catalogue of exhibits of insect enemies of forest and forest products, etc.," Bui. 48, Bureau of Ento- 
mology, U. S. Department of Agriculture, 1904, p. 38. 
"On the study of forest entomology in America," Bui. 37, Bureau of Entomology, 1902, p. 22. 
