History of Forest Ecology 415 



tude. These men began to interpret the behavior of the tree and 

 the forest in the light of th3 fundamental laws to which all plant 

 life, without exception, is subjected. But the highest develop- 

 ment to date of the application of modern forest ecology to silvi- 

 cultural practice is to be found in the recent works of Wagner, 

 Mayr, Duesberg and others. 



The last decade has seen the development not only of modern 

 plant ecology, but it has likewise witnessed an important change in 

 the science of forestry in that it has introduced modern ecological 

 ideas into the practice of silviculture. Just as modern plant ecology 

 in its stiidy oj vegetative units, is today concerned with the investigation 

 and determination of habitat factors, in a similar manner modern 

 forest ecology is trying to explain every observation, whether it deals 

 with the individual tree, the forest formation, or u/ith some silvicultural 

 practice, in terms of one or more of the factors of the habitat. Not 

 only are we making use of broader ecological knowledge, but 

 foresters are studying their problems in a systematic manner, 

 making working plans for each investigation ; they are not relying 

 upon the blind, groping methods of the past to lead them, perchance 

 to the proper solution of their problems. In other words, empiri- 

 cism has called science to its aid. As Mayr points out, neither 

 empiricism nor science alone can solve the intricate and manifold 

 problems of forest building, as the Germans call silviculture ; it is 

 necessary to study first and then experiment, for only this method 

 of procedure will obviate costly, time-consimiing, and purposeless 

 silvicultural practice and lead to stable and rational forest man- 

 agement. 



There are four important silvicultural works of which I desire to 

 speak which really mark a new era for silviculture. In 1907, 

 Christoph Wagner published his Die Grundlagen der rdumlichen 

 Ordnung im Walde and two years later appeared Heinrich Mayr's 

 suggestive book Waldbau auf naturgesetslicher Grundlage. In 1910, 

 Duesberg wrote Der Wald also Erzieher and in 1912 Wagner wrote 

 a book on his pet system Der Blendersaumschlag und sein System. 

 These books mark the climax, up-to-date, of this new development. 



Wagner's first book is a valuable contribution to forestry litera- 

 ture. Most of the book is devoted to silviculture and deals with 

 the requirements of silviculture in formulating the principles of 

 local order. In this connection he places silviculture first and 

 regulation second. In his discussions of methods of reproduction. 



