260 ANNUAL REPOKT SMITHSONIAN INSTITUTION, 1915. 



It is only by a thorough understanding of such mutual adjustments 

 that the forester is capable of intelligently handling the forest. With 

 the great number of species that are found in this country, with the 

 great variety in climatic and other physical factors which influence 

 the form of the forest, it is self-evident that there are man}'^ forest 

 communities, each with distinctive biological characteristics, which 

 offer a wide field for scientific inquiry. Amid the great volume of 

 administrative phases of the work in the Forest Service this main 

 objective has never been lost sight of in handling the national forests. 

 The Forest Service is now spending nearly $300,000 annually for 

 research work ; it maintains eight forest experiment stations and one 

 thoroughly equipped forest-products laboratory, and is doing this 

 work solely to study the fundamental laws governing the life of the 

 forest and their effect upon the final product — wood. 



Forestry may be called tree sociology, and occupies among natural 

 sciences the same position as sociology among humanistic sciences. 

 Sociology may be based upon the physiological functions of man as 

 a biological individual. A physician, however, is not a sociologist, 

 and social phenomena can be understood and interpreted only in the 

 light of sociological knowledge. So also with forestry. Forestry 

 depends upon the anatomy and physiology of plants, but it is not 

 applied anatomy and physiology of plants. With foresters anatomy 

 and physiology of plants is not the immediate end, but enters only 

 as one of the essential parts, without which it is impossible to grasp 

 the processes that take place in the forest. 



As the science of tree societies, forestry really is a part of the 

 larger science dealing with plant associations, yet its development 

 was entirely independent of botanical geography. When the need 

 arose for the rational handling of timberlands no science of plant 

 association was in existence. Foresters were compelled to study the 

 biology of the forest by the best methods available; they used the 

 general scientific methods of investigation and developed their own 

 methods when the former proved inadequate. I am frank to admit 

 that the present knowledge of plant associations in botany ha« not 

 yet reached a point where foresters could leave wholly to botanists 

 the working out of the basic facts about the life of the forest which 

 are needed in the practice of forestry. Wlien the general science of 

 plant associations has reached a higher state of development the two 

 may possibly merge, but not until then. 



In developing the science of tree associations the forester has been 

 unquestionably favored by the fact that the forests, being the highest 

 expression of social plant life, afford the best opportunity for 

 observing it. 



The reason for the ability of forest trees to form most highly 

 organized plant societies lies in their mode of growth. Each annual 



