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 intensive management, raising questions about the functional role of species with no commercial value. Many of the questions facing forestry science-particularly those dealing with the relation between complexity and function-are precisely the ones confronting basic ecology. Over the past decade scientists have labored to develop ecosystem-based management approaches that maintain system complexity and function, and scientists have increasingly played nontraditional roles at the interface between biology, sociology, and policy.