The Sciences Underlying Forestry. 2j 



botany, geology, meteorology, with physics and chemistry as 

 hand-maidens, and zoology to a degree require attention. 



That portion of botany which may be segregated as dendrology, 

 the botany of trees, forms naturally the main basis. In this 

 connection let me point out that the arborescent vegetation is to 

 some extent sui generis; their persistence through centuries, the 

 long period of life, and their elevation above the rest of vegeta- 

 tion, which exposes them to the seasonal changes and hence sub- 

 jects them to the climatic factors throughout the whole year, make 

 trees exceptional organisms, and render their life history more 

 varied and of greater interest than that of the annually deciduous 

 plants of those half-woody plants which winter under the pro- 

 tection of the snow. 



But to study such segregated portion of the large field of 

 botanical science presupposes a certain amount of general botani- 

 cal knowledge. In order to know, recognize, and classify his crop 

 materials the methods of classification, the general anatomy, his- 

 tology, and physiology must be familiar to the forester. Soon, 

 however, specialization becomes necessary, and his botanical 

 studies must concentrate themselves upon the botany of trees, and 

 this does not mean mere descriptive, systematic dendrology, the 

 mere knowledge of the species, their classification and geograph- 

 ical distribution, but physiological and ecological or biological 

 dendrology, the life history of the tree in the individual and in 

 communities, a very special study, to which few botanists have as 

 yet given much attention. 



The knowledge of the species, the plant material, is a necessary 

 equipment, but the knowledge of the laws of tree growth and of 

 the life history of the limited number of species at least which 

 have forestal importance is infinitely more necessary. Only a 

 few species comparatively form the basis of forest production in 

 a given region: out of the 500 species of which this continent 

 boasts, hardly more than 100 are of economic significance. The 

 life history and development of these under varying conditions 

 needs to be known fully ; here depth is needed. 



It is only within very recent times that botanists have developed 

 systematically in the direction of ecologic studies, in studying the 

 relation of plants and plant communities to their surroundings 

 and to each other, a study which to the forester has been for a 

 century of greatest necessity and which he has carried on em- 



