458 A NATIONAL PLAN FOR AMERICAN FORESTRY 



Many of the burns in the western white pine type, for example, should 

 be planted with trees. About 200,000 acres of openings in the forest 

 where the vegetation is depleted, but where moisture conditions are 

 favorable, should be reseeded to herbaceous erosion control plants. 

 If practical methods for artificial reseeding of the drier low-elevation 

 forest ranges to forage plants can be developed, many of the areas, 

 now supporting a thin cover of annual plants, should be restored to a 

 perennial type of vegetation more typical of what they formerly 

 produced. 



Thorough research is justified to determine just what cover is most 

 satisfactory for the different exposures, soils, and other conditions, 

 how to restore and maintain such a cover, and what utilization if any 

 can be permitted under various watershed conditions. 



PACIFIC CASCADE DRAINAGES 



The region west of the Cascade Range of Oregon and Washington 

 (see fig. 14) is one of heavy precipitation, deep snows, and steep and 

 rugged topography, all conducive to heavy and rapid run-off. Over 

 most of the drainages the forest growth is dense, as a result of heavy 

 precipitation, fertile soils, and a long growing season. The forests 

 are predominantly Douglas fir, with western hemlock and silver fir 

 also prominent. At the higher elevations occur mountain hemlock 

 and alpine fir. A heavy undergrowth, principally of brush and ferns, 

 combines with the tree growth and thick litter to form a protective 

 cover for the slopes, which is unusually effective in conserving mois 

 ture and preventing erosion. The forest reaches elevations of 4,500 

 to 6,000 feet in the northern Cascades and 7,000 feet or more in the 

 southern. At the upper elevations the forest is mainly open and is 

 often difficult of access. Above the forest are rugged mountain 

 ridges and numerous peaks, several with glacial fields. Of the total 

 area of 49,450 square miles in these Pacific Cascade drainages 41,386 

 square miles (about 26,487,000 acres) is forested land or potential 

 forest land now bearing a brush cover. Of this area approximately 

 15,564,000 acres, principally the steep slopes of the Cascade Moun- 

 tains, has been classified as having a major watershed-protection 

 influence, 9,509,000 acres, largely bordering the Pacific coast, as 

 having a moderate influence, and 1,414,000 acres, chiefly on islands 

 in Puget Sound, as having only slight to no influence. 



Because of the extremely heavy precipitation, averaging from 50 to 

 75 inches and in some places totaling as much as 125 inches a year, the 

 heavy snowfall, which at the higher elevations totals 30 to 50 feet, 

 and the occurrence in winter of Chinook winds accompanied by warm 

 rains, floods are inevitable. Stream channels have, in the main, 

 adapted themselves to take care of large amounts of water. Occasion- 

 ally, however, floods do considerable damage to high-value land and 

 improvements. 



Owing to the abundance of water and the great fall in streams, these 

 drainages contain the greatest concentration of waterpower resources 

 in the United States. About 625,000 horsepower has already been 

 developed, at a cost of more than $65,000,000, and more than 4,500,000 

 horsepower remains to be developed. 



A very large population draws upon the water supplies of these 

 drainages for municipal use. Seattle, Tacoma, Portland, and prac- 



