44 



THE OUTLOOK FOR TIMBER IN THE UNITED STATES 



Table 31.— Area of commercial timberland, by owner class, 1952, 1962, and 1970, with projections to 2020 



[Million acres] 



Owner class 



1952 



1962 



1970 



Projections 





1980 



1990 



2000 



2020 



National Forest 



93. 1 



46. 1 



59. 5 



296. 2 



94.9 



44. 4 



62.5 



306. 4 



1 91. 9 



44. 2 



67. 3 



2 296. 2 



91. 2 



43. 5 



68. 4 



291. 2 



90.3 



43. 1 



69. 5 



286. 3 



89. 2 



42. 7 



70. 7 



281. 8 



87.4 



41. 9 



72.9 



272. 6 



Other public 



Forest industry. 



Farm and miscellaneous private. 





All owners 



495. 



508. 1 



499. 7 



494. 4 



489. 2 



484. 4 



474. 7 





1 Includes 5 million acres of National Forest land in 

 the Rocky Mountains not considered in projecting timber 

 supplies. These include small isolated patches and stringers 

 of productive forest land areas too unstable to harvest 

 with current technology, and lands where nontimber 

 uses predominate. 



statements also must be prepared before proceed- 

 ing with development of the remaining unroaded 

 areas. Legislation is pending, moreover, that 

 would extend the wilderness system to eastern 

 National Forests. In 1972 some 'half million acres 

 of eastern National Forest land was identified for 

 study of suitability as wilderness. 



Commercial timberlands in other Federal, State, 

 and local public ownerships, amounting to 44 

 million acres in 1970, are also projected to de- 

 crease somewhat as a result of continuing with- 

 drawals from timber harvesting of areas important 

 for nontimber uses. 



The upward trend in area of commercial timber- 

 land owned by forest industries through acquisi- 

 tions from other owners is projected to continue, 

 with a modest increase over the 1970 figure of 67 

 million acres. 



In this initial base projection by far the biggest 

 acreage change is estimated for nonindustrial 

 private owners. Forest areas available for timber 

 production on these holdings were assumed to 

 drop from an estimated 296 million acres in 1970 

 to 273 million acres by 2020. 



A BASE PROJECTION OF TIMBER SUPPLIES 

 WITH 1970 LEVELS OF MANAGEMENT 



This section presents a set of estimates of tim- 

 ber supplies that might be available in future 

 decades if the same level and type of timber 

 management as in 1970 continued, and timber 

 harvesting were based upon biological relation- 

 ships between growth and harvests, for example, 

 as suggested by recent trends. A summary of 

 these base projections for the United States 

 is first presented, followed by a description of 

 supply potentials in each of the four major 

 sections of the United States. 



2 Includes 1.1 million acres in Hawaii not considered 

 in projecting timber supplies. A large part of this area 

 (0.495 million acres) is in "other public" ownership. 



A later section of this chapter presents a set 

 of alternative projections of economically avail- 

 able timber supplies with alternative price levels, 

 related in part to these base projections and in 

 part to other factors bearing on timber operability 

 and availability. 



General Procedures 



Projections of timber supply were developed by 

 a stand table method utilizing rates of radial 

 growth, mortality, harvesting, and sapling in- 

 growth, together with growth constraint equations 

 related to basal area and other factors, based upon 

 data from remeasured Forest Survey plots. A 

 computer program was developed to per/form the 

 calculations required to project variables by 2-inch 

 tree diameter classes, with specified adjustments 

 for area changes and schedules of timber harvest- 

 ing. 3 The same procedure was used in reconciling 

 data from successive surveys, and in updating to 

 1970 Forest Survey data collected over the 

 previous 12 years or so. Growth rates and other 

 inputs used in this procedure reflect the effects of 

 management practices during the 10- to 15-year 

 period prior to 1970 when Survey field measure- 

 ments were taken. Each projection also was 

 evaluated to assure that supply estimates rep- 

 resented reasonable biological possibilities. 



Timber Harvesting Assumptions for Base Projections 



In addition to the amount and kind of cultural 

 measures and protection applied to the Nation's 

 commercial timberland, both timber harvesting 

 practices and the timing, amount, and composition 

 of timber harvests in relation to growth and 

 inventories will have major impacts on future 

 roundwood supplies. 



3 Larson, Robert W., and Marcus H. Goforth. TRAS — A 

 computer program for the projection of timber volume. 

 U.S. Dept. Agric, Agric. Handb. 377, 24 p. June 1970. 



