A NATIONAL PLAN FOE AMERICAN FORESTRY 



221 



TABLE 17. Present current annual growth of usable material on commercial forest 

 areas of the United States, by regions l 



i Exclusive of Alaska. Growth figures represent volume of wood without bark, as in estimates of timber 

 stand and drain. Board-foot volumes are on the basis of estimated lumber tally, assuming utilization con- 

 sistent with good practice in each region. The growth in cubic feet is for stem wood, including all trees 4 

 inches or more in diameter breast height; it includes the limbs in the hardwoods. 



Of nearly 12 billion board feet of saw- timber growth, over 70 per- 

 cent is softwood. Of the total growth of almost 9 billion cubic feet, 

 softwood comprises over 50 percent. More than one half of the saw- 

 timber growth and also of the total growth is in the South, which has 

 more than half of its forest area, or about 100 million acres, in growing 

 saw timber and cordwood. The growth in the Lake region, especially 

 for softwood, is strikingly low, owing primarily to the depletion of the 

 stock of saw timber and cordwood; only one fifth of the 56 million 

 acres of forest land bears growing saw timber or cordwood, and the 

 remainder is classed either as restocking with trees below cordwood 

 size, or as nonrestocking. 



The comparatively low figures for growth in the West about one 

 seventh of the country's total for all growth, and less than one fourth 

 for saw timber are explained by the fact that much of the forest land 

 in the West is covered with overmature timber which is making little 

 or no net growth, and a large portion of the remainder is either 

 deforested or covered with small reproduction. Moreover, the growth 

 rates are generally low in -the Rocky Mountain regions. 



THE RELATION OF CURRENT GROWTH TO DRAIN 



A simple comparison of current growth and drain means very little 

 except as the quantity of surplus old growth, the extent, location, and 

 condition of growing stock, and other pertinent factors are taken into 

 consideration. The national ratios of 5 to 1 for drain and growth of 

 material of saw-timber size, and of nearly 2 to 1 for material of saw- 

 timber and cordwood size combined, are the net results of widely 

 differing ^ conditions which operate broadly to divide the whole 

 country into three major growth sections. Table 18 shows regional 

 growth and drain estimates combined by the regional groups within 

 each of which the conditions in general are fairly similar. (See also 

 figures 20 and 21.) It also shows, for comparison with drain, as a 

 matter of importance, the saw-timber cut for lumber. 



