A MANUAL OF FORESTRY 



other species it prefers a deep, fertile, well-drained soil. It is 

 rather a tree of the hillside than of the plain, and especially 

 prefers cool glens or ravines, probably on account of the at- 

 mospheric moisture. 



It stands a great deal of shade, even surpassing the spruce in 

 this ability, and because of this is able to establish itself under 

 a dense cover. For this reason, hemlock trees of all ages are 

 common in a stand. 



Under the shade of a mature forest the growth of the average 

 hemlock is very slow. There is often a period of suppression of 

 from thirty to seventy and sometimes to two hundred years. 

 Even at this advanced age 1 if light is admitted a hemlock will 

 respond and show an increased growth. Trees of the same 

 diameter, and in the same stand often differ in age by more than 

 a century. A dominant tree with plenty of light may grow 

 fairly rapidly. 



Trees having a moderate amount of light begin to bear seed 

 when from thirty to fifty years old. As a rule seed is produced 

 abundantly every two or three years. The cones mature in a 

 single season and the seed falls during late autumn. It is often 

 carried considerable distances by the wind. The seed germinates 

 well on moss-covered logs and decayed stumps; in fresh mineral 

 soil; and in a moist, well-decomposed leaf litter. Seedlings may 

 be killed by too little shade and this explains why reproduction in 

 the open is not common as with pine and spruce. 



Although the hemlock is a shallow rooted species it is seldom 

 thrown by the wind. In the case of ground fires, however, the 

 tree suffers where other deeper rooted varieties escape injury. 

 The most common and worst injury to hemlock by wind is the 

 so-called "wind shake," which is a separation of the rings of the 

 wood caused by the tree being rocked back and forth. "Wind 

 shake" and "butt rot" often make it necessary to discard the 

 butt log or cut high stumps. As a whole the hemlock is fa irk- 

 free from serious insects or fungi. 



1 E. H. Frothinnluim, The Eastern Hemlock, No. 152, U. S. Dept. of Ajjri. 



