Scope of Dendrology in Forest Botany. 237 



Systematic dendrology. Here again the author is splitting 

 hairs with the "practical" and the "scientific." A botanist dis- 

 tinguishes herbaceous plants in the field by readily recognizable 

 "ear marks." This does not make him any less a botanist. 



Biological dendrology. A forest is a collection of trees of the 

 same or different species. The character of the forest is the sum 

 of the characters of the individuals composing it. It seems to 

 me that if one made a study of "the facts involved in the cli- 

 matic requirements of tree species, their edaphic needs, habits 

 of growth, tolerance, reproduction and so on," he would be 

 making "an analytical exploration of the ecological problems 

 embraced within these matters." But according to the author, 

 if he performed the work indicated under the first quotation he 

 would be in the domain of biological dendrology, while if he per- 

 formed the work indicated under the second quotation he would 

 be in the domain of silvics. I think this all I need to say of the 

 author's attempt to separate the two. 



It is possible that there may be a logical division between the 

 concept of biological dendrology and silvics, but the author 

 does not make it clear. It is helpful in many respects to regard 

 the forest as an organism, an entity, with its own structures and 

 functions and with environmental interactions differing from 

 those of an individual tree. The study of a forest from this 

 point of view might be called silvics, while the study of trees in 

 their ecological relationships as individuals might be called bio- 

 logical dendrology. For example, the reactions of the forest as 

 an entity upon light and temperature conditions, upon soil and 

 hydrographic conditions might be considered as a distinct com- 

 partment of forest knowledge. When, however, we begin to 

 apply these reactions in their influence upon living plants, we 

 must consider such plants as individuals, and then we fall back 

 into the domain of biological dendrology as defined above. For 

 example, if we study the influence of the forest as an organism 

 upon reproduction a.'^■ expressed by the kind or the nature of the 

 young growth, we are dealing with one of the components of the 

 forest, not with the forest as a whole. I do not know, however, 

 that the intergrading of these two concepts would be any greater 

 than that of other divisions of forest knowledge. 



