26 The New York State College of Forestry 



arborescent elsewhere. For example. Witch Hazel and Cordate 

 Willow are shrubs in New York State but become trees farther 

 south and west. Certain species of Ficns begin life as lianas but 

 ultimate!}' become arborescent. Again many woody plants which 

 are reduced to dwarfed, scraggly shrubs in the boreal zone, attain 

 to the dignity of large shrubs or even trees to the southward 

 where the}' are not forced to contend with such a hostile environ- 

 ment. In general the kinds of woody plants may be defined as 

 follows : 



1. A tree is a woody plant which attains a height of at least 

 twenty feet in a given locality and usually (not alwaj's) has but 

 a single self-supporting stem or trunk. 



2. A shrub is a woody plant which seldom exceeds twenty feet 

 in height in a given locality and usually (not always) has a num- 

 ber of stems. Many shrubs have prostrate primary stems 

 embedded in the. soil or leaf-mold which send up persistent sec- 

 ondary branches of fruticose habit. These arise at varying 

 intervals from the horizontal stem and appear as separate 

 individuals. 



3. A liana is a climbing woody vine. Lianas climb by twining, 

 clambering, aerial roots, tendrils, etc., and are characteristic fea- 

 tures of tropical rain forests. They are represented in our flora 

 by such woody vines as Virginia Creeper, Clematis, Moonseed 

 Vine, and the Wild Grape. 



