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CHAPTER 5 SUMMARY OF PART I PRODUCTION POTENTIAL OF UNITED STATES FORESTS It is entirely feasible to double the production of wood from the forests of the United States through the application of current technology, while continuing to manage our forests on a sustained yield basis. Whether or not it is economically feasible to do so is a different question. Whatever the answer, it must be understood that the increases in growth we prognosticate are only those resulting from management practices which we consider immediately reasonable and practicable. The total biological potential of forests is much greater. Our general conclusion, therefore, is that the biological productivity of the commercial forest lands of the United States is such that, where economic and social conditions permit, the net realizable growth of these forests could be doubled within half a century by the widespread application of proven silvicultural practices. Following our own lines of evidence and reasoning, we confirm the findings of others who have reached similar conclusions. We realize that political and economic restraints may result in a lesser increase in productivity. At the same time, we wish to point out that, with widespread application of intensive silvicultural practices, with complete use of our hardwood resources, and with complete tree use, our potential productivity would be closer to three times the present level rather than the doubling we feel is eminently practicable. We should note that, while the authors of the National Academy of Sciences1 report on Agricultural Production Efficiency (1975) point to the possibility that we may be approaching the limits of improvement of growth for some agricultural products, this does not hold for wood. Due to the long life span of tree crops and the relatively low historical intensity of their management, the practice of silviculture is far less advanced than the practice of agri- culture. Under the current state of the art, relatively modest investments in forest management will result in substantial increments in the biological production efficiency of trees. - 63 -
RESEARCH NEEDS Concerning the biological productivity of our forests, it is important to stress the great importance of a continuing research program designed to elucidate the various factors treated in this report. Despite the substantial level and generally high guality of past investigations, the issues raised are so new that they cannot have been sufficiently studied by forest scientists. Specifically, it is essential that we work toward the development of a revised and more broadly supported national forest survey that will present forest data on a collective biological basis, so that it can be interpreted at several levels of potential use as economic conditions change or are predicted to change. Ideally, forest survey dat^ should provide estimates of the volume of the total boles of trees and the weight of their total biomass by component parts. Such information should be generalized by species, forest types, and classes of site and size. In short, we need to generalize better than we can today from specific studies of complete tree analyses and forest ecosystem biomass studies to better predict the effects of fuller tree use and of different silvicultural management practices. Although considerable specific information exists on the biological and technical aspects of the various approaches to timber production under intensive management, substantial research is needed to predict the impact of such programs on site improvement, forest type conversion, reforestation, genetic improvement, weedings and thinnings of the area that can and should be involved, the results that can be expected, and the predicted cost-benefit relations. Large gains can also be expected from improved techniques for protecting forests from insects and diseases. The interaction of increasingly more complete tree use and the nutrient cycle within the forest is poorly under- stood, yet it is of critical importance. As more and more of the tree is harvested, a greater proportion of the nutrient capital is taken from the site. The replenishment of this nutrient capital through natural processes will ordinarily compensate for the long-cycle periodic removal of part of the boles of the largest trees. At the other extreme, short-cycle removal of much of the forest biomass may seriously "mine" the forest soil and have a deleterious effect on the forest site. We need to know how often and how much of the forest production can be safely removed by forest type and site class. Research must continue to develop managed-stand yield tables to predict accurately timber production as affected by cultural treatments. Results will have wide - 64 -
applicability in improving forest survey predictions and land-use planning decisions. A topic not covered in this report but critical to the problem is the computation of allowable cut for the forests of the United States. We have touched upon only one aspect of this, the allowable cut effect. The assumptions and techniques by which the permissible annual cut of each class of ownership is computed will have great impact upon how and to what extent the biological growth of our forests is productively harvested. Still another area requiring research is the socio- economic aspect of forestry. We have speculated at length about the motives of small woodland owners and the environmentally oriented groups toward intensive forestry; yet we know far too little about the impacts of these groups on future timber growing and on wood supplies. Finally, information is needed on the energy requirements of growing timber. Research is largely lacking on this newly critical issue, so much so that the topic was omitted from our survey. In the future, energy costs, productions, and balances will figure in forest management decisions just as ecological and economic factors already do, and immediate effort is needed to develop this important facet. - 65 -
BEFERENCES - PART I Alich, J.A., Jr. and R.E. Inman (1974) Effective utilization of solar energy to produce clean fuel. Stanford Research Institute Project Number 2643. 161 pp. Andrulot, E.R., L.P. Blackwell and P.V. Burns (1972) Effects of thinning on yield of loblolly pine in central Louisiana. Louisiana Tech University Bulletin 6. 145 pp. Assman, E. (1970) Principles of forest yield study. Pergamon Press, New York. 506 pp. Barber, J.C. (1968) Tree improvement â how much can we increase wood production? United States Department of Agriculture, Forest Service, ms. 14 pp. Bengtson, G.W. (1968) Potential increases in wood production through fertilization of forest land in the South. Proceedings 47th Annual Meeting Appalachian Section. Society of American Foresters February 8-9, 1968: 31-38 Boyce, S.G. (1974) The biological potential for the Southeast. Southern Lumberman 229:71-75. Carmean, W.H. and A. Vasilevsky (1971) Site index comparisons for tree species in northern Minnesota. United States Department of Agriculture, Forest Service, Research Paper NC-65. 8 pp. Clawson, M., Editor (1974) Forest policy for the future. Resources for the Future, Inc. Washington, D.C. 360 pp. Deitchman, G.H. and A.W. Green (1965) Relations between western white pine site index and tree height of several associated species. United States Department of Agriculture, Forest Service, Research Paper INT-22. 28 pp. Doolittle, W.T. (1958) Site index comparisons for several forest species in the Southern Appalachians. Soil Science Society of America, Proceedings 22:455-458. Eriksson, H. (1967) A comparison between the yield figures for permanent sample plots and those for the stand as a whole. Department of Forest Yield Research, The Royal College of Forestry, Stockholm. Research Note 14. 72 pp. Gardner, R.B. and D.w. Hann (1972) Utilization of lodgepole pine logging residues in Wyoming increases fiber yield. - 66 -
United States Department of Agriculture, Forest Service Research Note INT-160. 6 pp. Gingrich, S.F. (1971) Management of young and intermediate stands of upland hardwoods. United States Department of Agriculture, Forest Service, Research Paper NE-195. 26 PP- Gordon, J.C. (1975) The productive potential of woody plants. Iowa State Journal of Research 49(3):267-274. Grantham, J.B. (1974) Status of timber utilization on the Pacific Coast. United States Department of Agriculture, Forest Service General Technical Report PNW-29. 42 pp. Grantham, J.B. and T.H. Ellis (1974). Potentials of wood for producing energy. Journal of Forestry 72 (9): 552- 556. Greentree Associates (1973) Critigue of the outlook for timber in the United States. Lansing, Michigan. 51 pp. Hair, D. and R.B. Phelps (1971) The demand and price situation for forest products 1972-73. United States Department of Agriculture, Forest Service, Miscellaneous Publication 1239. 87 pp. Hansen, R.A. and N.E. Johnson (1974) Culture of the growing forest: one company's approach. Journal of Forestry 72:686-691 Keays, J.L. (1971) Complete-tree utilization. An analysis of the literature. Forest Products Laboratory, Canadian Forestry Service Information Report, VP-X-69. 5 vols. Koch, P. (1974) Harvesting southern pine with taproots can extend pulpwood resource significantly. Journal of Forestry 72(5):266-268. Lassen, L.E. and D. Hair (1970) Potential gains in wood supplies through improved technology. Journal of Forestry 68(7):404-407. Maclean, C.D. and C.L. Eolsinger. (1973) Estimating productivity on sites with a low stocking capacity. United States Department of Agriculture, Forest Service Research Paper PHW-152. 18 pp. Miller, W.D. and T.E. Maki (1957) Planting pines in pocosins. Journal of Forestry 55:659-663. - 67 -
Murphy, P.A. and H.A. Knight (1974) Hardwood resources on southern pine sites. Forest Products Journal 24 (7): 13- 16. Napier, D.A. (1972) Total tree harvesting doubles fiber tonnage from aspen stand. Journal of Forestry 70:343- 344. National Academy of Sciences, (1975) Agricultural Production Efficiency. Committee on Agricultural Production Efficiency. Washington, D.C.: National Academy of Sciences, 199 pp. Ostrom, C.E. and C.B. Gibbs (1973) Biological potential for and biological constraints on timber yield. United States Department of Agriculture, Forest Service, draft ms. 40 pp. Ovington, J.D. (1965) Woodlands. English Universities Press. London, 154 pp. PAPTE (1973) Report of the president's advisory panel on timber and the environment. United States Government Printing Office 541 pp. Ribe, J.H. (1974) A review of short rotation forestry with comments on prospect of meeting future demand for forest-products. University of Maine at Orono, Life Sciences and Agriculture Experiment Station Miscellaneous Report, 160. 52 pp. Rudolph, P.O. (1950) Forest plantations in the Lake States. United States Department of Agriculture, Technical Bulletin 1010. 171 pp. Schreiner, E.J. (1970) Mini-rotation forestry. United States Department of Agriculture, Forest Service Research Paper NE-174. 32 pp. Schultz, R.P. (1975) Intensive culture of southern pines: maximum yields on short rotations. Iowa State Journal of Research 49 (3):325-337. Southern Forest Resource Analysis Committee (1969) The South's third forest. 111 pp. Spurr, S.H. (1952) Forest inventory. New York: The Ronald Press Co. Spurr, S.H. (1963) Growth and mortality of a 1925 planting of Pinus radiata on pumice. New Zealand Journal of Forestry 8(4):560-569. - 68 -
Spurr, S.H. (1963) Growth of Douglas-fir in New Zealand. New Zealand Forest Service Technical Paper 43. 54 pp. Spurr, S.H. (1974) Timber and the environment: reflections on American forest policy. Journal of Forestry 72(1) :17-20. Staebler, G.R. (1972) Concentrating timber production efforts. Society of American Foresters, Proceedings 1972 National Convention, Hot Springs, Arkansas. pp. 74-81. Stoeckler, J.H. (1963) A review of forest and swamp drainage methods in Northern Europe. Journal of Forestry 61:99- 104. Strand, R.F. and R.E. Miller (1969) Douglas-fir growth can be increased. Report from Pacific Northwest shows. Forest Industries. October 1969. pp. 29-31. Szego, G.C. and C.C. Kemp (1973) Energy forests and fuel plantations. Chemtech, May 1973. pp. 275-284. UNESCO (1971) Productivity of forest ecosystems: proceedings of the Brussels symposium. UNESCO. Paris. 707 pp. United States Department of Agriculture (1974) The outlook for timber in the United States. Forest Service. Forest Resource Report 20. 374 pp. Vaux, H.J. (1973) How much land do we need for timber growing? Journal of Forestry 71 (7):399-403. Whittaker, R.H. (1966) Forest dimensions and production in the Great Smoky Mountains. Ecology, 77:103-121. Hikstrom, J.H. and S.B. Hutchison (1971) Stratification of forest land for timber management planning on the western National Forests. United States Department of Agriculture, Forest Service Research Paper INT-108. 38 pp. Young, C.E., Jr. and R.H. Brendemuehl (1973) Response of slash pine to drainage and rainfall. United States Department of Agriculture, Forest Service Research. Note SE-186. 8 pp. Young, H.E. (1964) The complete tree concept â a challenge and an opportunity. Proceedings of the Society of American Foresters, Denver, Colorado, 1964:231-233. Young, H.E. (1975) The enormous potential of the forests. Journal of Forestry 73(2):99-102. - 69 -
