216 THE BOOK OF FORESTRY 
THE OAKS 
The oak family is by all means the most important 
of all the broadleaf genera found in the Northern 
Hemisphere as over one-third the total cut of hardwoods 
is supplied by the various oaks. Of the fifty-two species 
found in the United States five are shrubs; twenty- 
three of the tree species belong to the white oak group 
and twenty-four to the black oak group. The dis- 
tinctive feature of this genus is the fruit—an acorn— 
and the length of time it takes to mature this fruit 
divides the white from the black oak group. In the 
former the acorn matures in one vear, with one minor 
exception, while with the black oaks two seasons must 
elapse before the fruit is mature consequently if a tree 
belongs to the black oak group it will have small acorns 
on the tree in the winter which will ripen during the 
next season. 
