794 General and Applied Biology 



during cutting operations; the nonreplacement of trees cut, by new, young 

 trees. (3) Animals, which destroy young trees, seedHngs, seeds; by using 

 forests for grazing purposes, particularly if the forest is burned over for 

 grazing purposes. 



Forest conservation measures include: (1) Replanting burned-over 

 areas. (2) Replanting forests which have been cut. (3) Removal of 

 undesirable trees and vegetation to permit better growth of desirable 

 varieties. (4) Prevention of forest tree diseases. (5) Providing basic 

 protection for all forests, qualifying for cooperative Federal-state protec- 

 tion under the Clarke-McNary Act. (6) Education of careless hunters, 

 campers, etc. If the following rules are followed faithfully, many forest 

 fires can be prevented: (a) Hold and pinch all matches until they are 

 cold; (b) crush out cigarette, cigar, and pipe ashes (use a rock or ash 

 tray); (c) drown all camp fires, stir and drown again; (d) learn and 

 obey laws about burning grass, brush, trash, etc.; (7) Building more fire 

 lookout posts and patrol stations. (8) Discontinuance of practice of burn- 

 ing-over forests for grazing purposes. (9) Wiser and more economical 

 use of timber. (10) Selection of better species of trees for particular 

 areas so that better qualities can be raised in a shorter time. 



Loss and Conservation of Soils. — Soils are lost by ( 1 ) wind erosion 

 and (2) water erosion. Soils may be blown away because there is in- 

 sufficient surface vegetation to hold the soil particles. In a similar man- 

 ner, water currents may wash away great quantities of soil. It is esti- 

 mated that forty tons of soil per acre are washed away from land with a 

 2 per cent slope during one rainy season. Recent dust storms have re- 

 moved large amounts of soil for hundreds of miles, causing not only the 

 loss of soil where it is needed, but placing it where It Is not desired. The 

 removal of trees, grasses, and other vegetation has resulted in water and 

 wind erosion, with the loss of the water-retaining humus as well as min- 

 erals essential for plant growth. Soil washed into streams interferes with 

 plant and animal life there in addition to filling up rivers, lakes, and 

 ponds, thus rendering them useless. This silt will quickly fill a body of 

 water behind a dam, so that the original purposes of the dam are de- 

 feated. Soil erosion also Interferes with the water supply of cities, for 

 much effort is required to remove these soil particles from the water 

 supply. Many streams are polluted because of soil particles which inter- 

 fere with the normal growth and dc\elopment of plants and animals 

 normally inhabiting them. 



Soil conservation measures include ( 1 ) the reestablishment of the 

 proper types of vegetation (trees, grasses, crops, etc.) to hold the soil par- 



