Timber Inventory 



The commercial timberlands of the United States 

 contained some 792 bilhon cubic feet of roundwood 

 in 1977 (table 6.14). 



Size and species of timber. — About 64 percent of 

 the total colume was in sawtimber trees (trees large 

 enough to contain at least one log suitable for the 

 manufacture of lubmer). Another 26 percent was in 

 poletimber trees (trees from 5 inches in diameter at 

 breast height to sawtimber size and now or prospec- 

 tively suitable for industrial roundwood). The remain- 

 ing 10 percent of all roundwood volume was in 

 rough, rotten, and salvable dead trees. Some of this 

 latter material may be suitable for lumber and veneer, 

 but most of it is usable only for pulp, fuel, and other 

 products where log quality requirements are flexible. 



There are substantial volumes of fiber that are not 

 included in the inventory statistics above. It has been 

 estimated, for example, that about 40 percent of the 

 total fiber in a tree occurs in the top, limbs, bark, and 

 foliage." In addition, nearly 25 percent of the total 

 above ground fiber in the Nation's forests is in trees 

 less than 5.0 inches diameter at breast height. Little 

 use is being made of such material at the present time 

 because it is not economically feasible with existing 

 technology and with current costs of fiber from other 

 sources. This material does, however, represent a 

 large potential source of fiber for pulp, fuel, and the 

 production of various petrochemical substitutes. 



Softwoods predominate in the Nation's timber 

 inventory, accounting for about 61 percent of the 

 total volume of all classes of timber, and nearly two- 



thirds of the growing stock — poletimber and saw- 

 timber trees. The softwood growing stock inventories 

 are mostly on the Pacific Coast (table 6. 15). This dis- 

 tribution, in constrast to that for commercial timber- 

 land, which is predominately in the eastern United 

 States, reflects the concentration of timber in western 

 old-growth stands where high volumes per acre are 

 common. 



National softwood growing stock inventories in- 

 creased 7 percent from 1952 to 1977. Inventories in 

 the North and South nearly doubled and there was a 

 small increase in the Rocky Mountains. However, as 

 a result of the harvest of old-growth stands there was 

 a continuing decline, about 15 percent, on the Pacific 

 Coast. National and regional softwood sawtimber 

 inventories showed similar trends, although the 

 changes on a percentage basis were somewhat 

 smaller. 



Hardwoods made up about 36 percent of all classes 

 of standing timber in 1977, and about 23 percent of 

 all sawtimber. More than 45 percent of all hardwood 

 growing stock was in the North — nearly all the rest 

 was in the South. The 255 billion cubic feet of hard- 

 wood growing stock in 1977 was slightly more than 

 double that of 1952. Practically all of the increase 

 took place in the eastern United States with the North 

 and South making equal contributions. 



Ownership of timber. — The largest portion of the 

 softwood timber inventory in 1977 was in National 

 Forests, including some 46 percent of all softwood 

 growing stock and more than half of the softwood 

 sawtimber (table 6.16). Most of this timber was in 

 old-growth stands in the western United States, with 



Table 6.14— Timber inventories on commercial timberlands in the United States, by class of 



material and species group, January 1, 1977 





All species 



Softwoods 





Class of timber 



Volume 



Proportion 



Total 



Eastern 



Western 



Hardwoods 



Growing stocl< trees: 

 Sawtimber trees: 

 Sawlog portion 

 Upper-stem portion 



Million 

 cubic feet 



452,786 

 52,042 



Percent 



57.1 

 6.6 



Million 

 cubic feet 



341,904 

 25,917 



Million 

 cubic feet 



82,017 

 10,333 



Million 

 cubic feet 



259,887 

 15,584 



Million 

 cubic feet 



110,882 

 26,125 



Total 



504,828 



63.7 



367,821 



92,350 



275,471 



137,007 



Poletimber trees 



206,140 



26.0 



87,958 



49,217 



38,741 



118,182 



Total 



710,968 



89.7 



455,779 



141,567 



314,212 



255,189 



Salvable dead trees 

 Rough trees 

 Rotten trees 



14,114 

 44,042 

 23,247 



1.8 

 5.6 

 2.9 



13,197 

 7,396 

 8,261 



278 

 4,552 

 1,515 



12,919 

 2,844 

 6,746 



917 

 36,646 

 14,986 



All classes 



792,371 



100.0 



484,633 



147,912 



336,721 



307,738 



Source: See source note table 6.13. 



229 



