TIMBER: FORESTRY 



391 



362. Hard woods. North America furnishes more species of 

 trees valuable for hard-wood timber than any other region 

 of similar area with a temperate climate. About eighty kinds 

 are of economic importance, and of these, six or eight are oaks, 

 classed for commercial purposes as white and red or black 

 oaks. White oak is stronger than the red kinds, but has not 



so coarse a grain, so that ^ _^ ^ 



for cabinetmaking the red 

 oaks are more ornamental, 

 and often in " quartered " 

 cut lumber (sawed radially) 

 are very showy. More than 

 half of our supply of hard- 

 wood timber is furnished 

 by the oaks (of about nine- 

 teen species). 



Among the woods of 

 broad-leaved trees, tulip- 

 wood, from the tulip tree 

 (Liriodendrori), is next in 

 importance to the various 

 kinds of oak. It is variously 

 known as yellow poplar, 

 and whitewood, and grows 

 in abundance in the Ohio 

 basin and southward, but 

 does not, like oak, form 

 separate forests. The wood 

 is very soft and workable, 'and has largely taken the place of 

 white pine for the inside finish of houses and in the manu- 

 facture of woodenware. 



Ash, beech, birch, chestnut, elm, maple, red gum, and syca- 

 more are some of the most important hard woods for general 

 purposes besides those already mentioned. For especial pur- 

 poses certain woods not of the greatest value for all-round 

 construction are highly prized; as hickory for ax and other 



FIG. 317. Cross section of ring-porous 

 wood of sassafras 



a.r, boundaries of the " annual rings" ; the 

 wood is ring-porous because the ducts (here 

 shown as oval or roundish spots) are most 

 abundant in the spring wood, almost lack- 

 ing in autumn wood. Magnified fifteen di- 

 ameters. Photomicrograph by R. B. Hough 



