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. Feothingham, Forest Examiner. 



CONTENTS. 



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. — 

 is 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—15 1 



