14 PKELIMINAKY STUDY OF 



undersized or defective tie will be accepted if hewed when it would 

 be rejected if sawed. Also it is somewhat less expensive to make 

 and deliver a hewed tie, if the amount of timber wasted is not con- 

 sidered. Sometimes mine props and'cordwood can be made from 

 the tops of tie trees, thus saving wood which would otherwise be 

 wasted. 



MINE TIMBERS. 



One of the principal uses for second-growth timber within 

 the Cumberland Plateau is in connection with the coal mining 

 industry, which is of great importance in that region. Tim- 

 ber of low grade and small size is suitable for props, caps, and mine 

 ties, which are usually either round or split. Red oak and chest- 

 nut are the chief woods used for these purposes. Considerable saw 

 timber is also used inside the mines for brattice, rails, and other 

 purposes, and outside for the construction and repair of trestles 

 and tipples. The number of props required varies greatly with 

 the character of the rock covering which forms the roof of the coal 

 seam. An investigation of the amount of timber used by coal mines 

 in Eastern Kentucky showed an average consumption of about 41/2 

 board feet per ton of coal mined. On this basis the amount of tim- 

 ber used in mining coal in Tennessee for the year 1909 would be 

 27,930,000 board feet. Of course a large part of this timber con- 

 sists of material too small to make lumber. 



OTHER PRODUCTS. 



The manufacture of tight cooperage stock, for which white 

 oak is the chief wood required, reaches its greatest importance 

 in the Cumberland Plateau region. Elm and hickory are com- 

 monly used for hoops. A high grade of timber is consumed in 

 making tight staves, and a great deal of the tree is wasted, espe- 

 cially if the staves are split out in the woods. In the manufacture 

 of slack staves, on the other hand, close utilization is the rule. Oak, 

 gum, and cottonwood are the chief woods used, and are taken 

 largely from the bottom lands of West Tennessee. Table 2 shows 

 the production of cooperage stock in 1909.* 



Boxes and box veneers are also produced in considerable amount. 

 In East Tennessee yellow poplar is used for this purpose, especially 



* Compiled by the Bureau of the Census in cooperation with the Department 

 of Agriculture, Forest Service. 



