CHAPTER VI 



The Present Forests of North America 



The United States occupies the second place among the nations 

 of the Xorthern Hemisphere in the extent of its forests, Russia 

 having first rank and Canada third, so that North America as a 

 whole probably ranks first in forest resources among the northern 

 continents. 



North America may be conveniently divided for a consideration 

 of its forests into four major regions. These are: (1) A northern 

 sub-Arctic region; (2) a temperate Atlantic region; (3) a temperate 

 Pacific region, and (4) a Central American-Antillean region. Each 

 of these regions naturally embrace a great variety of soils, climate 

 and topography and consequently a variety of different forest 

 associations. All become modified toward their limits and are not 

 to be sharply bounded except by broad and gradually changing 

 transition zones, but in their typical expression they are exceedingly 

 well marked. 



The Northern region is essentially a part of that Holarctic belt 

 of vegetation that encircles the globe in the region bordering the 

 Arctic tundra. In North America it constitutes a broad belt of 

 sub-Arctic (Hudsonian) woodland extending from the tundra or 

 northern limit of tree growth southward to a rather indefinite 

 boundary at about latitude 53° and hence covering between 10^ 

 and 15° of latitude. It stretches across the continent from southern 

 Labrador, south of Hudson Bay and then northwestward to 

 within the Arctic Circle in the lower Mackenzie basin and in 

 northern Alaska, reaching the Pacific at Cook Inlet. 



This whole area receives an ample rainfall except toward its 

 southwestern limits. It occupies throughout nearly its whole 

 extent a glaciated area with innumerable lakes, streams, and ex- 

 tensive swamps, especially in the region between Hudson Bay and 

 Lake Winnipeg, where the country is largely swampy with a tree 



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