26 BULLETIN 523, U. S. DEPARTMENT OF AGRICULTURE. 
ashes. The 74 pounds of wood are composed of 37 pounds of car- 
bon (charcoal), 4.4 pounds of hydrogen, and 32 pounds of oxygen.” * 
DURABILITY IN CONTACT WITH THE GROUND. 
Ash wood is only moderately durable in contact with the ground. 
It is used to a minor extent for posts, rails, and gate bars in locali- 
ties where better timber is not available. White and green ash are 
as durable as red oak, butternut, and red elm; while black ash is 
considerably more so because of its large per cent of heartwood, which 
is due to slow growth. White and green ash are more durable than 
aspen, basswood, box elder, cottonwood, hard and soft maples, hick- 
ory, white elm, and willow, and are preferable to these trees for un- 
treated fence posts. Fence posts from these two ashes will last from 
6 to 12 years, depending on size, percentage of heartwood, method of | 
seasoning, the character of the site in which the post is set, and the 
season of the year when the tree is cut. Black ash posts will usually 
last from 12 to 15 years. 
DISEASES AND INSECTS WHICH ATTACK ASH TIMBER. 
Standing ash timber is not subject to extensive damage by disease. 
Although a number of diseases have been found on the different 
species of ash, only one has done much serious harm, white rot. 
Diseased trees are mostly those whose vitality has been weakened by 
old age, fire, or generally adverse conditions. 
White rot occurs in the heartwood of the trunk and main branches, 
and is caused by the fungus Polyporus fraxinophilus, which turns 
the wood into a mass of yellow pulp. This disease is common in 
overmature green ash in the lower Ohio Valley and in the Missis- 
sippi River bottoms, near their confluence; it is also common on 
white ash near the western limit of its range in Iowa, Missouri, 
Kansas, and Oklahoma, where it occurs on dry limestone hills and 
where 90 per cent of the trees are infected.” 
The two insects which are of primary importance in connection — 
with ash products are: (1) the ash wood borer (Neoclytus capraea) 
which attacks the logs and bolts from trees felled in the late fall, 
winter, and early spring, and destroys the sapwood; and, (2) the 
Lyctus powder post beetle which attacks the sapwood of products 
after they have been seasoned for a year or more. The Bureau of 
Entomology, U. S. Department of Agriculture, Washington, D. C., 
_has made special studies of these insects and has discovered practical 
1From Bulletin 10 of the Division of Forestry, Department of Agriculture, ‘‘ Timber: 
Elementary Discussion of Characteristics and Properties of Wood,” by Filibert Roth. 
2Full discussion of this disease is contained in Bulletin No. 32 of the Bureau of 
Plant Industry, ‘‘A Disease of the White Ash Caused by Polyporus frazrinophilus. 
