86 
Ohio Biological Survey 
and when well sheltered out of doors retains about 15 per cent. The 
amount is by no means constant but varies with the humidity and 
temperature of the air. 
The real substance of wood is something more than one and 
one-half times the weight of water, and the actual wood fiber of the 
basswood or poplar is just as heavy as that of the oak or hickory. 
Fig. 7. A shellbark hickory that has grown under good forest conditions. The 
long unbranched trunk furnishes timber, free from knots, that is always in 
demand. 
