WESTERN CONIFEROUS FOREST 



461 



out the forests are bright with spring flowers. Later in 

 the season the leaves cast so much shade that the forest 

 floor is either free from small plants or can support those 

 only with broad thin leaves able to work with very weak 

 light. This illustrates a principle of common application 

 in that the chief vegetation type is the most powerful 

 factor in determining the nature of the plants associated 

 with it. Moreover the nature of the plant cover also 

 exerts a powerful influence on the type of animals in- 



FiG. 126. — The Highest Type of Deciduous Forest. A beech- 

 maple woods in Michigan, with hemlock also. This forest develops 

 into a type in which the beech, by reason of its dense shade, becomes 

 the only tree. (Vestal.) 



habiting the same region. A forest of beeches and oaks 

 affords both abundant food and suitable homes for such 

 types of animals as squirrels, which could survive with 

 difficulty in a prairie, or desert. 



The Western Coniferous Forest (Fig. 127) occupies 

 a region that is on the whole cooler in summer and in 

 some parts warmer in winter than that of the Deciduous 

 Forest. Moreover, the rains are more copious in winter 



