Qualities and Uses of the Woods of Ohio 
81 
Fig. 4, A border of young catalpa trees near the University woocllot. 
Durability. —The duration or lasting- quality of wood depends 
upon the nature of the wood and the conditions surrounding the wood 
The character of the wood fiber; the presence of resinous gums, tan¬ 
nin or other substances, the power to absorb moisture,—the percent¬ 
age of sap wood, the rate of growth, and the freedom from knots, all 
influence the durability of wood. Many woods, if kept dry, are ex¬ 
tremely durable, while others fall a prey to dry rot fungus or insect 
injury. Some woods that are durable when dry, decay rapidly when 
subject to repeated moisture and partial drying, as is seen when 
woods are used for posts. Locust, red cedar, and cypress are more 
subject to fungus diseases when living than when dead. 
It has been clearly demonstrated that fence posts from rapid¬ 
growing trees decay sooner than those from slow-growing trees from 
the same species. Of the woods grown in Ohio, osage orange makes 
the most durable fence posts. This is followed by yellow locust, red 
cedar, red mulberry, chestnut, and white oak. Bur oak and chestnut 
oak and a few other varieties are about as durable in the form of 
posts as white oak. A white oak or a cedar growing' raj)idly in the 
open may be much less durable, however, than a slow-erowine oak 
or cedar in the forest, and a locust or catalpa grown in rich soil is 
much less durable than those that grow on a thin soil. 
