xvi North American Trees 



TREE CHARACTERS 



A brief discussion of the structural and silvical characters, 

 an understanding of which is necessary in identifying trees, is 

 presented here to aid students without previous botanical 

 training. 



Definition of a tree. There is no clear-cut line of demarcation 

 between a tree and a shrub, and it is often impossible to place 

 a plant definitely in one group or the other. Frequently a species 

 treelike under favorable environmental conditions will be 

 shrublike over most of its range. In general, height, form, and 

 diameter must be taken into account in determining the classi- 

 fication of a doubtful form. In this manual, a tree is defined 

 as a woody plant having one well-defined stem, a more or less 

 definitely formed crown, and attaining a minimum height 

 of fifteen to twenty feet and a diameter of not less than 

 two inches. 



Terminology. While appearing cumbersome to the beginner, 

 the use of technical terms in describing characters is often neces- 

 sary for a concise, accurate description. These technical terms 

 have been avoided wherever their omission did not impair the 

 meaning of the passage, and a glossary explaining all technical 

 terms used has been included. The student should familiarize 

 himself with the more commonly used terms early in his study 

 of the trees. 



Name. Most species of trees have been given one or many 

 common names which usually describe some character of the 

 tree and are easily learned by students. Unfortunately, these 

 common names have many limitations. Some are merely local, 

 others apply to two or more entirely diff^erent species, and some 

 apply to trees belonging to different genera. Because of this, 

 while common names may be useful and convenient, it is essen- 

 tial that each species of tree have a definite, individual name 

 that can be accepted throughout the world and which cannot 

 be applied to any other species. 



Botanists and scientists as a whole have agreed that these 

 scientific names should be in Latin, as this is a dead language 

 and not subject to change. Botanists have further agreed that 

 the name of a tree should consist of three parts: a generic 

 name referring the species to the group to which it belongs 

 and which is capitalized; a specific epithet referring to the single 

 species and beginning with a small letter; and the full or 

 abbreviated name of the authority or person first describing 



