Table 6.21 —Average net annual and potential growth per acre in the United States, 



by ownership and section, 1976^ 



Item 



Unit of 

 measure 



All 

 ownerships 



National 

 Forest 



Other 

 public 



Forest 

 industry 



Farmer 



and other 



private 



North: 

 Current 

 Potential 

 Current/potential 



Cubic feet 



Cubic feet 



Percent 



35.3 

 65.3 

 54.1 



42.6 

 62.3 

 68.4 



36.4 

 59.7 

 61.0 



44.0 

 74.4 

 59.0 



32.9 

 65.2 

 50.5 



South: 

 Current 

 Potential 

 Current/ potential 



Cubic feet 



Cubic feet 



Percent 



55.5 

 77.3 

 71.8 



57.0 

 71.1 

 80.2 



52.8 

 71.0 

 74.4 



60.2 

 83.3 

 72.3 



54.5 

 76.5 

 71.1 



Rocky Mountains and 

 Great Plains: 

 Current 

 Potential 

 Current/potential 



Cubic feet 



Cubic feet 



Percent 



28.7 

 59.5 

 48.2 



30.4 

 63.7 

 47.7 



24.5 

 54.5 

 50.0 



49.9 

 74.1 

 67.3 



23.4 

 49.7 

 47.0 



Pacific Coast: 

 Current 

 Potential 

 Current/potential 



Cubic feet 



Cubic feet 



Percent 



49.3 

 97.0 

 50.8 



30.3 

 90.8 

 33.4 



53.1 

 88.0 

 60.3 



79.3 



119.5 



66.5 



62.0 

 98.9 

 62.6 



Total: 

 Current 

 Potential 

 Current/potential 



Cubic feet 



Cubic feet 



Percent 



44.9 

 74.2 

 60.5 



35.1 

 74.1 

 47.4 



41.6 

 68.3 

 60.9 



59.2 

 87.3 

 67.8 



45.0 

 71.9 

 62.6 



' Potential growth is defined as the average net growth attainable in fully stocked 

 natural stands. Much higher growth rates can be attained in intensively managed 

 stands. 



timber supplies and other measures of the timber 

 resource such as inventories and net annual growth, if 

 recent trends in the basic determinants continue dur- 

 ing the next half century. ^^ Specifically, these base 

 level projections rest upon the assumptions that: (1) 

 Radial growth and mortality rates during the late 

 1960's and early 1970's will continue, (2) commercial 

 timberland area will continue to decline throughout 

 the projection period to 446 million acres by 2030, (3) 

 stumpage prices measured in 1967 dollars (net of 

 inflation or deflation) will continue to increase in the 

 future as they have in the 1960's and 1970's, (4) timber 

 harvests (projected supplies) will respond to stump- 

 age price and inventory changes much as they have 

 during the base period from 1950-74, and (5) the cur- 

 rent even-flow harvest policies and the nontimber 

 management objectives on public lands will set ceil- 

 ings, above which public harvests will not rise. 

 Although not an explicit forest management assump- 

 tion, the radial growth and mortality rates which are 



'''The projections are deriveci from a computerized model which 

 recursively simulates inventory changes and roundwood harvests. 

 This model is described in appendix 4 of the report "An analysis of 

 the timber situation in the United States, 1952-2030," op cit. This 

 appendix also contains a brief discussion of other timber resource 

 projection models and citations of the pertinent recent literature. 



Source: See source note table 6.13. 



assumed to continue were greatly influenced by the 

 forest management activity that occurred during the 

 same time period. 



In the simplest terms, the projections show what 

 would happen to timber supplies if the trends in the 

 major forces affecting the resource in the base period 

 used in making the projections continue to 2030. Pro- 

 jections of the consequences of the continuation of 

 recent trends are an essential first step in evaluating 

 the need for changes in timber policies and programs. 



This is the basic purpose of this analysis. There is 

 no implication that the projected trends in timber 

 supplies will continue during the next five decades. In 

 fact, it is expected that as a result of the description of 

 these trends, and the associated economic, social, and 

 environmental implications, actions will be taken to 

 change the trends in ways which are considered to be 

 more desirable from the standpoint of the society. 



Projected Base Level Timber Supplies 



The base level timber supply projections prepared 

 using these and related assumptions show the supply 

 of softwood timber continuing to increase in the 

 future, but at a slower rate than between 1962 and 

 1976. The increase is accompanied by a sizable shift 



237 



