26 BULLETIN 523, U. S. DEPARTMENT OF AGRICULTURE. 



ashes. The T4 poimcls of wood are composed of o7 pounds of car- 

 bon (charcoal), 4.4 pounds of hydroj^en. 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. AYliite and green ash are 

 as durable as red oak. butternut, and red elm; while black ash is 

 considerabh'^ 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 w^ill 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 firixinophilus, 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 w^ood borer {Neoclytus capraea) 

 which attacks the logs and bolts from trees felled in the late fall, 

 winter, ajid early spring, and destroys the sapw^ood; 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, 1). C, 

 has made special studies of these insects and has discovered practical 



' From Bulletin 10 of the Division of Forestry, Department of Agriculture, "Timber: 

 El'-mentary Discussion of Characteristics and I'roperties of Wood," by Filibert Roth. 



* Full dis( usKion of this disease is contained in Bulletin No. 32 of the Bureau of 

 Plant Industry, " A Disease of the White Ash Caused by I'vlyporus Jnuinoiiliilus. 



