SYLVICULTURE. 



Moist sea winds, after passing one chain allow the forest to 

 grow on the next chain only above the altitude of the gaps in the 

 first chain. 



The following table shows the composition of the forest of the 

 United States and of Canada, under the influence ©f the climate: 



Percentage of forest area occupied by: 



In United States. In Canada. 



Tropical forest V-Zjc ^% 



Sub-tropical forest 15 % 0% 



Forest of the moderately warm zone 75 % 10% 



Forest of the moderately cold and alpine zone. . 9ya7o ^O^c 



The United States contain two big and one minor forest region, 

 namely the 



Atlantic forest region; 



North Mexican forest region; 



Pacific forest region. 



The Atlantic and the Pacific forest join under the influence of 

 the Hudson Bay winds at 52 degrees latitude, in Assiniboia. There 

 are no prairies proper north of this latitude. 



The tropical forest shows no seasons. Its species are evergreen. 

 In the United States it is found only at the extreme southern point 

 of Florida. 



The sub-tropical foi-est is characterized by the evergreen broad- 

 leaved trees, and i;^ the zone of rice and oranges, extending in east- 

 ern North America to 35 degrees, in western North America to 

 40 degrees, latitude. 



The moderately warm forest region is the zone of tlie broad- 

 leaved deciduoiis trees, of corn, vine and wheat. 



The moderately cold forest region is that of the evergreen 

 conifers too cold for the production of corn. 



In North Carolina a trip from the coast to the high Balsams 

 leads the traveler from the northernmost limit of the sub-tropical 

 through the moderately ^varm forest region into the southernmost 

 limit of the moderately cold forest region which sets in at about 

 6,000 ft. elevation. 



A. The Atlantic forest. 



I. Eastern tropical forest. Mahogany occiu's only as a small 

 tree; Palms and other typically tropical orders (Sapotaceae, Ebon- 

 aceae. Euphorbia ceae, Verbenaceae) compose the forest. It must 

 be remembered that Southern Florida exliibits only the extreme 

 northern occurrence of the tropical forest. 



IS 



