BULLETIN OF THE 
No. 152 
Contribution from the Forest Service, Henry S. Graves, Forester 
February 3, 1915. 
THE EASTERN HEMLOCK. 1 
{Tsuga canadensis (Linn.) Carr.) 
By E. H. Frothingham, Forest Examiner. 
CONTENTS. 
Page. 
Introduction « 1 
Geographical range 2 
Commercial range 3 
Amount of standing timber , 4 
Value of standing hemlock 5 
Utilization of hemlock 7 
Structure and development of the tree 15 
Associated species 21 
Effects of light, soil, and moisture on the 
composition of the stand 22 
Reproduction 23 
Rate of growth 24 
Susceptibility to injury 27 
Hemlock in forest management 29 
Appendix 31 
INTRODUCTION. 
Though excelled in most respects by other trees in the region of 
its growth, eastern hemlock is none the less a most important mem- 
ber of the remaining old-growth forests. Its lumber, once held 
nearly worthless, now serves many purposes for which pine was 
formerly demanded; its wood supplies more raw material for paper 
pulp than does any other in the United States except spruce, while 
the amount of its bark used for tanning exceeds that of all other 
native species combined. Compared with pine, hemlock has been 
lumbered for only a short time, but this exploitation, accompanied 
as it has often been by waste and fire, has already greatly reduced 
the supply of standing timber. If the present rate of cutting con- 
tinues hemlock will before very long be as scarce as old-growth pine. 
In spite of its present importance, hemlock is not a tree of promise 
for forest planting. White and red pine will yield better lumber in 
a much shorter time and on poorer soils, are less suceptible to decay, 
and are more easily grown. Spruce serves as well for the protection 
of watersheds and stream sources, and produces better pulpwood 
i There are two species of hemlock in the eastern United States, but one — Tsuga caroliniana Engelm. — 
h restricted to the Southern Appalachians, and is of only local importance. This bulletin treats only 
of the other species — Tsuga canadensis (Linn.) Carr. 
Note. — This bulletin describes the more important characteristics of hemlock, presents tables of its 
volume and rate of growth, and gives the chief facts regarding its utilization. Acknowledgment is due to 
Messrs. E. M. Griffith, State Forester of Wisconsin, and R. S. Kellogg, Secretary of the National Lum- 
ber Manufacturers Association, for assistance rendered in the field study and in the course of preparation 
of this bulletin. 
60235°— Bull. 152— II 
