THE FORESTS OF ALASKA. 



11 



raising of this region above an earlier level has resulted in stream- 

 cutting, which obscures its original plateau character. It is in the 

 extensive valleys and on the adjacent slopes of the Yukon, Tanana, 

 and Kuskokwim rivers and their tributaries that the interior forests 

 reach their best development. 



The Rocky Mountain region is a comparatively narrow elonga- 

 tion of the Rockv Mountain svstem of North America, and stretches 



o 



Fig. 1. — Map of Alaska and adjacent regions, Aleutian Islands omitted. 



across northern Alaska nearly from east to west. The mountains of 

 this region reach a considerable though in no case a noteworthy 

 height. On their southern slope head many streams which empty 

 into the Yukon; those on the northern slope empty into the Arctic 

 Ocean. 



The Arctic slope region, lying north of the Rocky Mountain region, 

 is composed of rolling tundras, in which truly Arctic conditions 

 prevail. It has been less explored than any other portion of Alaska. 



