478 



RELATION- TO ENVIRONMENT. 



trees of different heights, the canopy is said to be "compound" 

 or "storied." Where it is uneven, there are open places in 

 the canopy which admit more light, in which case the under- 

 growth may be different. The interior of the forest lies between 

 the canopy and the floor. It provides for aeration of the floor 

 and interior occupants, and also room for the boles or tree trunks 



Fig. 489. 



Mature forest of redwood (Sequoia sempervirens). (Bureau of Forestry U S. 

 Dept. Agr., Bull. 38.) 



(called by foresters the wood mass of the forest) which support 

 the canopy and provide the channels for communication and 

 food exchange between the floor and canopy. The canopy 

 manufactures the carbohydrate food and assimilates the mineral 

 and proteid substances absorbed by the roots in the soil; and 

 also gets rid of the surplus water needed for conveying food 

 materials from the floor to the place where they are elaborated. 

 It is the seat where energy is created for work, and also the 

 place for seed production. 



