(4) 



18 not wind di eseminated whereas birch and maple are both 

 distibuted by the wind. Frothingham, 19 15, states that: 

 "Sugar maple is the most generally aggrissive reproducer 

 throughout the beech- birch-maple type. This is un ~ 

 doubtedly due to the combined tolerance and seeding 

 qualities. Beech, which is probably more tolerant, does 

 not bear large seed crops annually and much of the seed 

 produced is destroyed by animals. Yellow birch, which 

 does bear seed each year, is less tolerant. Its light 

 winged seed are so widely dispersed, however, that many 

 fall where the crown shade is light enough to permit 

 the development of the seedlings. These are adaptable 

 to a great variety of seedbed conditions. Yellow 

 birch thus accomplishes through its reproductive 

 aggressiveness often more than beech can accomplish 

 through its extreme shade endurance." 



