A NATIONAL PLAN FOR AMERICAN FORESTRY 93 



But toward the end of the last century, as wholesale and heedless 

 deforestation spread over more and more of the headwaters of streams 

 used for navigation and for irrigation and domestic water, the accumu- 

 lating evidence of direct observation forced recognition of the impor- 

 tance of forests in protecting many watersheds. The act of Congress 

 of 1897 which made " maintaining favorable conditions of water 

 flow" one of the two purposes of the administration of national forests 

 did not, of course, undertake to establish by legislative enactment a 

 scientific law of universal applicability. It did take into cognizance 

 a relationship between forest cover, erosion and run-off, proven in 

 numerous instances both at home and abroad. It recognized that 

 America is not immune to the disasters which have followed defores- 

 tation of watersheds in other countries. The act of 1911 which made 

 protection of headwaters of navigable streams the basis for purchase 

 of national forest areas in the eastern United States, gave further 

 formal recognition of the watershed protection value of forests. 



Specific data bearing on this function of forest cover are given 

 elsewhere in this report. Research and observation by trained men 

 show that in many of the forest regions deforestation starts processes 

 of flashy run-off and erosion which affect adversely water supplies 

 and navigation. In late years impressive evidence has accumulated 

 showing the prevalence of erosion on once forested hill and bluff lands 

 which have been heavily grazed or used for agriculture. Destruc- 

 tion of the fertility and usability of the lands through sheet and gully 

 erosion has already removed many millions of acres from agricul- 

 tural use, and is in fact one of the chief reasons for the widespread 

 abandonment of this class of land. Dumping of sand and silt into 

 the streams has created problems of diking, overflow, and destruction 

 of navigability far from the source of the eroded material. 



Maintenance of forest cover to protect watersheds is not necessary 

 on every part of every watershed. But estimates given elsewhere in 

 this report show that there is a very large area of land which must 

 be kept under forest or restored to forests if the watersheds of the 

 country are to be kept in good condition. Lands producing commer- 

 cial timber are not the only source of concern. In the West, particu- 

 larly, large areas covered with inferior tree growth or brush have high 

 value for protection of water and soil. Like the commercial forest 

 lands, their protective value is quickly impaired by fire and over- 

 grazing. 



FORESTS AS A SOURCE OF RECREATION 



The pioneer had little interest in the forest as an environment for 

 recreation. Variously he hunted in it, used it as a source of wood, 

 or struggled to annihilate it. As part of his normal environment, 

 he necessarily accepted it. And his opportunities for recreation were 

 few. 



Later, as urbanization proceeded and wealth and leisure increased, 

 more and more people acquired the means and the desire to leave 

 their normal environment of the city, for at least part of each year. 

 Along with journeys to foreign lands and to the seashore, the forests 

 in many parts of the country acquired a recognized value for outdoor 

 recreation of a primitive and simple sort. The Maine woods, the 

 White Mountains, the Adirondacks, the Colorado Rockies, and the 

 Sierra Nevadas became noted for their recreational values and 

 attractiveness. 



