152 FIRST BOOK OF FORESTRY 



Lumber is graded chiefly according to size and defects, 

 such as knots, cracks, discolored or decayed spots, and 

 unequal thickness. A board entirely free from any of 

 these defects is "■ clear," and it is evident that young trees 

 and badly cleaned trees are not likely to furnish much of 

 this valuable material. Generally hardwoods are graded 

 much more severely than conifers, and the cheaper always 

 more severely than the dearer kinds. 



For flooring, decking, and other purposes, boards are 

 often classified into " rift " and " bastard," or tangent, as 

 it should be called. In rift boards the rings stand nearly 

 vertical, or never less than forty-five degrees to the sur- 

 face, as seen in Fig. 58. Rift boards shrink less and wear 

 better, and therefore bring better prices. 



Lumber is regular merchandise in all parts of our coun- 

 tr}'^, and every town has its lumber yards, just as it has 

 other stores, where regular lines of lumber, in stock sizes 

 and grades, may be bought. 



Aside from firewood the greater part of all timber in 

 our country is cut into lumber, and it has been estimated 

 that over thirty billion feet B.M. were used each year 

 during the last quarter of a century. Of this enormous 

 amount about seventy-five per cent is pine, spruce, hemlock, 

 red fir, and other coniferous material, and twenty-five per 

 cent oak, ash, elm, and other hardwoods. Of the conifers 

 the white pine has for years furnished about fifty per cent, 

 while of tlie hardwoods about thirty-five per cent is oak. 



