TREES AND LUMBER 



17 



steam "nigger," and a similar operation is performed on the 

 opposite side. 



By easily-controlled machinery, the log is revolved or 

 moved into different positions to be sawed into boards. It is 

 sent from the saw to the edger and the cross-cut, or butting, 

 saw on "live" rollers which revolve on a horizontal table and 

 transmit the boards at a rate of 200 to 250 feet per minute 



FIG. 1. Methods of sawing FIG. 2. End of log, showing 

 lumber. A, slash-sawing; B, annual rings and medullary 

 quarter-sawing. rays. 



from one place to another. Finally, the boards, now known 

 as lumber, are transferred to a shed, where they are sorted as 

 to size, quality and cut, and then again transferred out of 

 doors to be piled for air-seasoning until sold for construction 

 purposes. 



Boards are usually slash-sawed, the term used for parallel 

 sawing (A, Fig. 1). However, they are also rift-sawed or 

 quarter-sawed, which means that the saw cut is radial, as 

 shown in B, Fig. 1. The advantage of the radially-sawed 

 board is that the edges rather than the sides of the fiber of the 

 wood form the surface of the board and thereby make a more 

 even grain and one which wears better. 



3. Tree Growth. When a tree is sawed down, the sawed 

 end will show concentric rings (Fig. 2). Those near the cen- 



