[Chap. LIU THE VEGETATION OF NORTH AMERICA 795 



woodlands and die depletion of our agricultural, game, and recreational 

 resources. This belated awakening has resulted in the initiation of wide- 

 spread research in land classification and utilization. Sincere attempts 

 are now being made to apply the results of scientific research to the 

 complex problems of reforestation, range improvement, soil conservation, 

 game management, stream control, and recreational facilities. 



Detailed knowledge of the original vegetation of America as it was 

 when the explorers and first settlers saw it is a valuable index to climatic 

 conditions in relation to the growth of different kinds of forests, crop 

 plants, and grass. Natural vegetation is a reliable index of the possibili- 

 ties of plant growth, because it portrays the results of the operation of 

 both climatic and soil factors on plants over a long period of time. The 

 original soils no longer exist; and many years of natural processes and 

 intelligent procedure on the part of man will be necessary to restore 

 the qualities that made possible the best growth of trees and cultivated 

 plants. We can decrease the rate of present wastage and follow pro- 

 cedures that will speed up the redevelopment of top soil where we are 

 now farming the lowest soil horizon, or its "parent material." 



REFERENCES 



Bennett, H. H. Soil Conservation. McGraw-Hill Book Company, Inc. 1939. 



Lord, R. Forest Outings. Papers by 30 foresters on the use of national forests 

 as recreation. Edited by Russel Lord. 4to. Washington, D. C. Superin- 

 tendent of Documents. 1940. 



Shantz, H. L., and R. Zon. Natural Vegetation. Part I. Section E. Atlas of 

 American Agriculture. 1924. The Agricultural Atlas also contains informa- 

 tion on climate and soils. 



Westveld, R, H. Applied Silviculture in the United States. John Wiley & Sons, 

 Inc. 1939. 



Many articles on the vegetation of the world may be found in the journals: 

 Ecology, Ecological Monographs, and the British Journal of Ecology. 



