178 FOREST UTILIZATION WOOD USES AND ECONOMICS 



now constitutes the second most important use of our forests and is 

 next to lumber in volume. Large quantities are still used on our 

 farms, where the average family consumption is about 17 cords per 

 annum. In the rural districts of the South, East, and Lake States, 

 wood is the chief fuel. In the Pacific Northwest, hogged fuelwood 

 from sawmill waste is widely used in domestic furnaces as well as for 

 furnishing industrial heat and power. Fuel value is directly related 

 to specific gravity. The resinous woods like the pines and Douglas fir 

 have higher heating values than non-resinous woods, provided they 

 have the same specific gravity. The most valuable woods for fuel in 

 order of importance are hickory, oak, beech, birch, maple, ash, and 

 elm. The most valuable softwoods in order of importance are tama- 

 rack, longleaf pine, Douglas fir, other southern pines, lodgepole pine, 

 and white pine. 



Under favorable circumstances, one man can fell, chop, and stack 

 one cord of wood per day. Recently, gasoline engines generally fur- 

 nished in a tractor have been commonly employed to buck up limbs, 

 tops, and defective wood into cordwood. The slabs, edgings, and 

 trimmings of most of the small mills, and of many of the large 

 mills, are used for fuel, either for domestic or industrial purposes. 

 For domestic purposes fuelwood is generally cut into 12- to 18-inch 

 lengths. Much 4-foot fuel is used in domestic furnaces in the North- 

 west. 



5. Veneers and Plywood. The use of wood in manufacture of 

 veneers has advanced strikingly during recent years compared to the 

 general use of wood. The principal veneer woods are Douglas fir, 

 red gum, southern pine, and ponderosa pine; they find extensive ap- 

 plication for shipping containers and for built-up stock or plywood for 

 doors, panels, furniture parts, drawer bottoms, and automobile parts. 

 Plywood is used for shipping containers in place of the former solid 

 boards, paper, or fiber boards. The use of wood for veneers and 

 plywood has doubled in 10 years. In addition to the species men- 

 tioned, ash, birch, oak, maple, elm, basswood, black walnut and many 

 other species are valuable for this purpose. 



Veneers are made by three processes: 



1. Rotary method, that is by turning a bolt or large log of wood 



against a knife, thus cutting continuous sheets of wood as 

 shown in the illustration. 



2. The slicing method by which sharp knives are sent against a 



stationary flitch, and 



3. Sawed veneer. 



