54 The Neiv York State College of Forestry 



bj^ acute or flat-topped, anastomosing ridges, as in Ash or But- 

 ternut. In some of the Hickories, the shellbarked species, the 

 bark exfoliates in broad plates, while in the Hornbeam it is flnely 

 shreddy. Beech and Blue Beech are characterized by a smooth 

 bark which fails to become rough, even with age. The bark of 

 some of the Cherries and Birches is comparatively smooth and 

 m.arked with prominent horizontal lenticels. Dog^vood, Persim- 

 mon, and Black Gum exhibit the so-called alligator bark, the 

 vertical ridges being interrupted by horizontal fissures which 

 give the appearance of alligator skin. Hackberiy is rough-barked 

 and in addition, often has gnarly excrescences. In many cases it 

 is difficult to put into words the distinctions which characterize 

 the bark of various species though they may be readily separated 

 in the field. 



The color of bark is extremely variable, both between species 

 and under different conditions of age, height, or location in the 

 same species. In many cases these variations between individuals 

 are puzzling to the novice and require a knowledge of the range 

 of variation to decipher species. The prevailing colors are gray, 

 brown, or black, but red and white bark are features of certain 

 trees. In general the mature bark is darker than that of the 

 branches and limbs, but exceptions to this occur. Moreover, the 

 color of the inner bark is likewise characteristic of certain species. 

 The inner bark of the Black Oak {Quercus velutina) is yeUow, 

 while that of Hemlock is purplish red. Butternut has a yellow 

 inner bark from which a yellow dye may be obtained. The bark 

 of many species is a source of valuable forest products such as 

 tannin, paper and rope fibers, dyes and cork. 



