INTRODUCTION 27 



DEFINITION OF TREE, SHRUB, ETC. 



Ill addition to the specific variations already mentioned, plants 

 also vary in size from the largest trees to organisms invisible to 

 the naked eye. In regions colder, drier or hotter than ours it is 

 often difficult to draw the line between trees, shrubs and herbs; 

 but in Alabama the problem is relatively simple. However, it is 

 desirable to state just what is meant by these terms. 



Trees can be conveniently divided on the basis of size into two 

 classes, large and small. The former when mature nearly always 

 reach up to the top of the forest in which they grow, and have 

 trunks large enough so that an ordinary board, say a foot wide and 

 twelve feet long, can be sawn from them. (Each human genera- 

 tion, however, sees the average size of trees successively smaller, 

 on account of the continual cutting of the larger specimens by 

 lumbermen, and a tree which never exceeds a foot or two in 

 diameter might have been called a small tree by our grandfathers.) 



A small tree generally grows in the shade of other trees (un- 

 less it is a species that thrives best in sunlight, like the willow), 

 and is not large enough for lumber, but it should be large enough 

 to make a fence-post, and have its lowest limbs far enough from 

 the ground so that • one can walk under them without stooping. 

 The trunk is usually single and erect, but not necessarily so. A 

 most typical small tree is the dogwood. Of course either a large 

 or a small tree when young may look like a shrub ; but a person 

 seeing a totally unfamiliar tree in the juvenile stage can usually 

 recognize it as such by its erect habit, few branches, absence of 

 flowers or fruit, and the resemblance of its foliage to that of some 

 mature trees near by. There are indeed some species of trees which 

 vary in size all the way from shrub to tree, and in unfavorable soils 

 or climate may produce flowers and fruit when only a few feet 

 high. Examples of this in Alabama are the sassafras and white 

 bay. 



A shrub generally has several stems from the same root, or a 

 .single crooked or leaning stem, not large enough for a fence-post, 

 and seldom more than three inches in diameter.* Shrubs are as a 



*Typical large shrubs, which sometimes have stems several inches in 

 diameter, but branch too close to the ground to be called trees, are Abuts, 

 Hanwmclis and Kahnia. 



