40 FIRST BOOK OF FORESTRY 



the red fir disappears, and the forest is one of balsam and 

 hemlock with cedar. As we reach a height of five thou- 

 sand feet the complexion of the forest changes entirely ; 

 the dense forest of tall mountain balsam and hemlock 

 suddenly gives way to open, more or less interrupted 

 alpine park woods, composed of short, limby trees belong- 

 ing to entirely different species, the alpine balsam and 

 hemlock. 



Thus, we see that our inference was correct : the high 

 mountain woods of our country are generally conifers, 

 composed of few species, and are usually more or less 

 stunted at higher altitudes. Similarly these woods change 

 from below upwards, decreasing in complexity of compo- 

 sition as well as in size and quality of the timber; and 

 their vigor, or rate of growth and capacity to maintain 

 and renew themselves, also decreases. 



