CHAPTER XXII 



APPLIED ECOLOGY 



Plant ecology is the most intensely practical of the plant sciences. 

 It deals with the interrelations between plants and their environ- 

 ments and since man is an important part of the environment of 

 plants, therefore, ecology includes all the interrelations between man 

 and plants and hence all of applied botany. If, therefore, we were 

 to take ecology out of botany or any of its subdivisions there would 

 be nothing left that would have any application to the affairs of man. 

 For this reason it is essential that anyone preparing to pursue any 

 branch of economic biology be trained in ecology. 



Obviously it would require volumes to deal in a comprehensive 

 way with the entire field of applied ecology. In this chapter, there- 

 fore, we shall discuss briefly some of the most common applications, 

 primarily for the purpose of making clear the fact that ecology is a 

 practical science. 



150. Forest Ecology.— Forestry, wherever it is successfully prac- 

 tised, is based entirely upon ecological principles. Practical foresters 

 are realizing this more and more and are coming to recognize the 

 need of training in plant ecology for anyone who is preparing for 

 any phase of forestry as a life work. The forester should be per- 

 fectly familiar with the life cycles and the phenology of the trees 

 under his care. He should understand such physiological processes 

 as respiration, absorption, and transpiration and should know how 

 these and other activities of the plant are affected by such environ- 

 mental factors as heat, light, moisture, soil variations, etc. It is 

 necessary also that he understand the methods of reproduction of 

 each species, whether by seeds or by vegetative shoots, and the most 

 favorable conditions for reproduction. He should know what species 

 of trees are ecologically suited to the conditions in his forest, both 

 of native and foreign species, and whether they will grow best in 

 pure stands or in mixed stands. The purpose for which trees are 

 grown, whether for lumber, fence posts, railroad ties, etc., or whether 

 they are being grown as a windbreak or to prevent erosion, influences 

 the choice of species and makes it necessary to understand the char- 

 acteristics and habits of growth of the various kinds. In order to 

 properly care for and protect the forest it is necessary that the 



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