RECENT TRENDS IN FOREST LAND AND TIMBER RESOURCES 



Table 6. — Area of commercial timberland, by stand-size class and section, 1970 



15 



Stand-size class 



Total United States 



North 



South 



Rocky 

 Mountains 



Pacific 





Area 



Proportion 



Coast 



Sawtimber stands - 



Million 



acres 



215.9 



126. 7 



131.4 



20. 7 



Percent 



43.6 



25.6 



26.6 



4. 2 



Million 



acres 



59.0 



60. 2 



49. 2 



9.6 



Million 

 acres 



74.0 



46. 2 



67.6 



4.8 



Million 



acres 



36.6 



12. 1 



5.2 



2.7 



Million 

 acres 



46. 3 



Poletimber stands __ 



8. 3 



Seedling and sapling stands 



Nonstocked areas.. 



9.3 



3. 7 







All classes. . 



1 494. 7 



100.0 



177.9 



192.5 



56.6 



67. 6 







1 Not including 5 million acres of "unregulated" commercial timberland on National Forests in the Rocky Mountain 

 States. 



Table 7. — Area of commercial timberland, by sawtimber volume classes and section, 1970 



Sawtimber volume 



class (board feet 



per acre) 



Total 

 United States l 



North 



South 



Rocky 

 Mountains 



Pacific Coast 



Less than 1,500. 



1,500 to 5,000 . . 



Million 

 acres 

 243 

 138 

 114 



Percent 

 49 

 28 

 23 



Million 



acres 



114 



49 



15 



Percent 



64 



28 



8 



Million 



acres 



103 



62 



28 



Percent 

 53 

 32 

 15 



Million 



acres 



14 

 16 

 26 



Percent 

 25 

 29 

 46 



Million 



acres 



12 



11 



45 



Percent 

 18 

 16 



More than 5,000. . .. . 



66 



All classes 



495 



100 



178 



100 



193 



100 



57 



100 



68 



100 



1 Not including 5 million acres of "unregulated" commercial timberland on National Forests in the Rocky Mountain 

 States. 



Somewhat more than half of all sawtimber 

 stands were classed as softwood types (fig. 6). 

 Poletimber and seedling and sapling stands, on 

 the other hand, included much larger proportions 

 of hardwood types. 



Stand-size classes and type groups, 1970 



E^v'^ softwood types [ I hardwood types 



sawtimber 

 stands 



pole timber 

 stands 



seedling and 

 sapling stands 



nonstocked 



MILLION ACRES 



Figure 6 



Commercial timberlands classed as "non- 

 stocked" in 1970 (that is, with less than 10 percent 

 of the area occupied by growing stock trees) 

 amounted to about 21 million acres. These were 

 widely distributed in all sections. 



TIMBER GROWTH 



Net annual growth of timber (that is, total 

 annual growth less volumes of trees dying 

 annually) is of major interest in areas with pre- 

 dominantly young-growth forests as in the eastern 

 United States as a general indication of the present 

 or prospective capability of forest lands to supply 

 wood products. In old-growth forests of the 

 West, however, where net growth is usually 

 negligible because of heavy mortality, available 

 inventories of standing timber rather than net 

 growth will determine allowable harvests for some 

 time to come. 



Recent Trends in Timber Growth 



The rise in net annual growth of timber illus- 

 trates a major success story in American forestry. 

 In response to programs of forest fire control, tree 

 planting, and other forestry measures, net annual 

 growth of softwoods and hardwoods combined 

 increased 18 percent between 1952 and 1962, and 



