American Midland Naturalist Monograph No. 4 



Regions 



In comparing the vegetation of the western national parks and Isle Royale 

 it should be noted that these areas are widely distributed over major physio- 

 graphic regions of the West, fig. 1. 



Pacific Slope Region 



Pacific Northwest 



Olympic National Park 

 Mount Rainier National Park 



Southern Cascades 



Crater Lake National Park 

 Lassen Volcanic National Park 



Sierra Nevada 



Yosemite National Park 

 Kings Canyon National Park 

 Sequoia National Park 



Rocky Mountain Region 

 Northern Province 



Glacier National Park 



M.ddle Province 



Yellowstone National Park 

 Grand Teton National Park 



Southern Province 



Rocky Mountain National Park 



Southwest Region 



Mesa Verde National Park 

 Bryce Canyon National Park 

 Zion National Park 

 Grand Canyon National Park 



Great Lakes Region 



Isle Royale National Park 



Pacific Slope Region 



The national parks of the Pacific Slope are located in a portion of the 

 western chain of mountains which extends from Alaska to Mexico. They 

 range from Olympic and Mount Rainier National Parks in northern Wash- 

 ington, through the southern Cascades in which are located Crater Lake 

 and Lassen National Parks, to Yosemite, Kings Canyon, and Sequoia Na- 

 tional Parks in the southern Sierra Nevada. As one follows the crest of the 

 main mountain range from north to south, it may be observed that elevations 

 become steadily higher, increasing from 4,000 to 6,000 feet in the north to 

 10,000 to 14,500 feet in the south. This is exclusive of the volcanic peaks 

 of the Cascade Range which ascend to much greater heiphts than the crest 

 of the range. Timberline also becomes increasingly higher as one moves 

 southward. At Mount Rainier the limit of trees is at about 6,000 feet while 

 in Sequoia National Park trees are found growing at almost twice that 

 altitude. 



The Pacific Northwest is characterized by exceedingly dense and luxuri- 

 ant forests exemplified in the two national parks of northwestern Washington, 

 Olympic and Mount Rainier National Parks. These two areas are only about 

 100 miles apart airline, the former in the Olympic Mountains near the coast 

 and Mount Rainier further inland in the Cascade Mountains. The relatively 

 mild moist climate is due to the direct influence of the moisture-bearing winds 

 from the Pacific Ocean which tend to modify the temperatures of the areas 

 surrounding these glacier-covered peaks. 



To the south in the southern Cascades, which are separated from th:^ coast 



