abstracts: agriculture and forestry 161 



AGRICULTURE.— Soil erosion, W J McGee. Bulletin Bureau of 

 Soils, No. 71. Pp. 60, pis. 33. 1911. 



The destructive erosion of soils is treated as an abnormal condition in 

 the relation between soil and water and the treatment is introduced by 

 an outline of the normal work of water. The soil is considered as of 

 three parts, viz., soil-body, soil-fluid, and soil-gas; and its efficiency 

 (measured by productivity) is ascribed primarily to physical conditions 

 permitting free circulation of the, fluid and gaseous parts through the 

 soil body and into growing crops. A working coefficient for the agri- 

 cultural duty of water is brought out, i.e., the production of one-thou- 

 sandth part of its weight in useful plant crop. The duty of soil, measured 

 in terms of the first acre-foot, is' also defined as the annual production of 

 one-three hundred thirty-third of its weight of useful plant crop. The 

 normal work of water is sculpturing the land surface and producing vege- 

 tal cover in a state of nature is analyzed and compared with the work of 

 water under the conditions attending settlement and cultivation of the 

 country; and it is shown that destructive erosion is one of the conse- 

 quences of interference with natural conditions. The development of 

 erosion following deforestation and injudicious cultivation is illustrated 

 by photographs reproduced in the plates. Remedies for such erosion 

 are described and illustrated; they include treatment of the soil, treat- 

 ment of the cover, and treatment of slopes, in such manner as to tend 

 toward restoration of the normal interrelations between natural water 

 supply, cover, and slope — the specific aim of the treatment in each case 

 being such improvement in cultivation as to yield immediate profit, 

 coupled with progressive increase in value of the land treated. W J M. 



FORESTRY. — The Olympic National Forest: its resources and their 

 management. Findley Burns. Forest Service Bulletin No. 89. 

 Pp. 20, with map and illustrations. 1911. 



The Olympic National Forest in northwestern Washington, with an 

 area of 1,594,000 acres, contains one of the heaviest stands of timber in 

 the United States. It approximates 25,500,000,000 board feel , and 

 Forest is capable of producing a sustained annual yield of 250,000 

 board feet. Douglas fir, western hemlock, amabilis and grand fir, and 

 Sitka spruce are the principal species. Present conditions in the lumber 

 industry in the northwest would make it unwise to cut each year the 

 amount of timber the Forest is capable of yielding. The Olympic 

 Forest was set apart to establish a timber reserve which could he drawn 



