WOOD AND ITS USES 315 



to fifty feet with eleven inch tops. Because of their smaller diam- 

 eters and greater lengths, poles are logged separately from saw 

 logs. Felling is usually done in the winter and the poles are peeled 

 of their bark in the woods during the spring or early summer, 

 after which they are removed from the woods to be seasoned prior 

 to preservative treatment or use. 



Great quantities of pilings are used, particularly in seaboard 

 regions, for docks, wharves and piers. Grade crossing elimina- 

 tions, highway bridges and railroad trestles demand large 

 amounts throughout the country. In general, the same species 

 are used for both poles and piling, the latter demanding greater 

 strength and straightness in order to drive properly without 

 splitting, but less durability, since much of the piling is driven 

 underground where decay and insect damage are negligible 

 factors. Piling is cut as close as possible to the point where it is to 

 be used. When piling of lengths greater than a hundred feet is 

 required, it is of Douglas fir, since this is the only species capable 

 of supplying this size, of the necessary quality. 



Fence posts. — Estimates place the number offence posts used 

 annually, most of them on farms and ranches, along highways 

 and railroads, at about 600,000,000. In general, the farm wood- 

 lot is the greatest producer of posts, though in some parts of the 

 country considerable quantities are produced as an incidental 

 product on large logging operations. They offer great oppor- 

 tunity for efficient forest utilization, since many of them are 

 produced from tops which are too small for saw logs, and from 

 thinnings in young growing forest stands. The leading species, 

 used because of their outstanding durability, include eastern 

 and western red cedar, redwood, cypress, mulberry, black 

 locust, and Osage orange. A second group would include chest- 

 nut, honey locust, white oak, northern and southern white cedar, 

 catalpa, and bur oak. Butt-treating the posts with a preservative 

 greatly increases their life, and makes it possible to use many of 

 the much less durable woods, not mentioned above. 



Shingles. — In spite of the increased use of so-called "fire- 

 proof composition roofing materials in the last twenty years, 

 shingle manufacture continues to be an important forest industry. 

 It is claimed that with proper manufacture, seasoning, and use, 



