154 FOREST UTILIZATION INDUSTRIAL FORESTRY 



where it is graded according to freedom from defects and blemishes, 

 and is sorted for piling. All the 2" x 4" pieces 10' long are placed in 

 one pile, the 2" x 6"s, 16' long are placed in another pile, and the 

 V x 10" boards in still another pile. There should be a separate pile 

 for each size and grade. 



After the lumber has been air-seasoned in the pile for four to ten 

 months or more, it is ready for shipment to market. Many mills are 

 putting green lumber directly from the sawing department to the dry 

 kiln, which may be either a compartment or a progressive type of 

 kiln, and subjected to certain temperatures and humidities to elimi- 

 nate moisture without degrading or destroying the full value of the 

 lumber product. About 50% of the weight of wood is moisture. This 

 must be largely eliminated before the wood is further manufactured or 

 used. Some lumber is first air-seasoned, as in hardwoods, and later 

 kiln-dried before being finally manufactured into furniture, flooring, 

 doors, and interior finish. 



Principal Species of Lumber and Producing States. The principal 

 species of lumber produced in our sawmills in order of importance 

 are: (1) southern pine; (2) Douglas fir; (3) ponderosa pine; (4) oak; 

 (5) white pine, including both northern and Idaho; (6) hemlock, in- 

 cluding both eastern and western; (7) red gum; (8) cypress; (9) 

 maple; (10) spruce; (11) redwood; (12) tupelo; 13) poplar; (14) 

 birch, and several miscellaneous varieties. 



Southern pine comprises about 30% of all our lumber, and Douglas 

 fir about an equal amount. The first two species therefore comprise 

 about 59% of all our lumber, and the first three, 72%. 



Hardwood lumber production has recently fallen off from about 

 21% of all lumber produced in 1919 to about 14%, and conversely, 

 softwoods have increased in volume from 79% to 86%. 



The principal lumber producing states in order of importance are: 



(1) Washington; (2) Oregon; (3) California; (4) Louisiana; (5) 

 Alabama; (6) Mississippi; (7) Texas; (8) North Carolina; (9) South 

 Carolina; (10) Florida; (11) Arkansas; (12) Idaho; and (13) Vir- 

 ginia. The first two states represent 38% of the total lumber output, 

 producing largely Douglas fir and western hemlock. These two states 

 produce 96% of all the Douglas fir; California produces largely pon- 

 derosa pine and considerable quantities of redwood and sugar pine. 

 The next eight states in order produce principally southern pine, and 

 they are also the centers of hardwood output. On account of the 

 vast available areas for southern pine and the favorable climate and 

 quick rate of growth, southern pine will always be a very important 



