114 



ELEMENTARY FORESTRY. 



large numbers. Deer, moose, elk and other similar animals 

 are likewise injurious in forests and when abundant may do 

 much damage, though on account of their comparatively 

 small number they do but slight injury. 



Severe Winters. These may injure many kinds of young 

 seedlings which rhen two or three years old will be perfectly 

 hardy Seedlings of such kinds should be dug at the end of 

 the first season's errowth and be heeled in over winter or pro- 

 tected by a mulch or earth covering in winter. 



Alternate Freezing and Thawing. Seedlings are often thrown 

 out of the ground by alternate freezing and thawing, and in 

 this way have their roots broken. This is most likely to hap- 



Figure 27. HEAVING OUT BY FROST, (a) Tree in 

 natural position, (b) Drawn up by alternate freezing 

 and thawing. 



pen where the ground is bare; if covered with leaves or grass 

 or shaded in other ways this seldom happens. The best pre- 

 ventive is to mulch the surface soil with leaves or other simi- 

 lar material, but as mice generally like to live in such places 



