The Scientific Basis of Forestry

Over the past two decades forestry in the United States has diverged into two approaches with quite different objectives and scientific priorities. The management focus of most industrial lands is on increasing productivity of wood fiber via plantations and various cultural tools, especially genetic selection, fertilization, and control of noncrop vegetation. Federal forest management has shifted from a similar focus to greater emphasis on protecting diversity and water. Issues of long-term sustainability are important regardless of ownership. Science has played and continues to play a fundamental role in all aspects. Selection for fast-growing genotypes has increased yields on the order of 10% to 20% depending on species. Fertilization often increases growth significantly but responses are variable and difficult to predict. Significant questions remain concerning the sustainability of intensive forestry, particularly when practiced over wide areas. Soils are heavily impacted by some harvesting practices, and the degree to which damage can be repaired by fertilizers is an important scientific issue. Intensive forestry often results in increased pest problems. In at least one case (fusiform rust in southern pines), a pest has been contained by selecting resistant cultivars, a situation that may or may not be evolutionarily stable. Species diversity is clearly reduced under 435 0066-4162/98/1120-0435$08.00 P1: KKK/mbg P2: ARS/ary QC: ARS/kba T1: ARS September 17, 1998 14:48 Annual Reviews AR067-16