Treesearch

Regenerating northern red oak (Quercus rubra L.) on high-quality growing sites is a continuing problem in the central Appalachian region. Competing species usually exhibit faster height growth after regeneration harvests compared to oak reproduction. The probability of advance oak reproduction becoming codominant in the new stand is positively related to seedling size at the time of the regeneration harvest. Silvicultural techniques are needed that stimulate the growth of oak seedlings before overstory removal without stimulating the growth of competing species. In this study, reproduction...

Stand dynamics and tree growth in even-aged hardwood stands can be influenced by manipulating relative stand density, species composition, and stand structure. Land managers need quantitative information on the effect of vegetation manipulation to prescribe stand treatments that are appropriate for specific management objectives. Sixty-year-old stands composed of black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), and American beech (Fagus grandifolia Ehrh.) were thinned to 45, 60, and 75% relative density as measured by the stocking guide...

A growing interest in managing forest ecosystems calls for decision models that take into account attribute goals for large forest areas while continuing to recognize the individual stand as a basic unit of forest management. A dynamic, nonlinear forest management model is described that schedules silvicultural treatments for individual stands that are linked by multi-stand management constraints. A growth model useful for many eastern forest types accounts for stand dynamics resulting from cutting decisions. This modeling approach provides a framework for coordinating management goals...

Deferment cutting is designed to regenerate a variety of high-quality hardwood species and promote a two-age stand structure for aesthetic, wildlife habitat, and other non-timber binefits. Basal area is reduced enough so that it resembles a seedtree or shelterwood practice in that some overstory trees are retained while all other trees are cut (Figure 1). However, in deferment cutting the residual trees are not cut once the reproduction becomes established as in even-age practices. Instead, the harvest of the residual trees is deferred until new reproduction is between 40 and 80 years old,...

Formulations for determining conservation plans for sensitive wildlife species must account for economic costs of habitat protection and uncertainties about how wildlife populations will respond. This paper describes such a formulation and addresses the computational challenge of solving it. The problem is to determine the cost-efficient level of habitat protection that satisfies a viability constraint for a sensitive wildlife population. The viability constraint requires a high probability of attaining a population size target. Because of the complexity of wildlife prediction models,...

Of the more than 2000 exotic insects now established in the United States (US Congress 1993), more than 400 feed on trees and shrubs (Haack et al. 1997b, Mattsonet et al. 1994, Niemela and Mattson 1996).Several of these exotic insects have greatly altered forest ecosystems in the US (Campbell and Schlarbaum 1994, Ciesla 1993, Liebhold etal. 1995, Wallner 1996).

Cultural practices can be applied in even-age stands to reallocate site resources to selected crop trees. Precornrnercial thinning in sapling stands can increase diameter growth and improve species composition of trees in the main canopy. Commercial thinning in sawtimber stands also increases diameter growth of crop trees, improves residual stand quality, and removes trees that would die absent thinning. Silviculturists need quantitative information on the response of particular species to thinning treatments to meet specific management objectives. In this study, 7- to 80-year-old northern...

Pulpwood production in the Lake States decreased from 9.6 million cords in 1995 to 9.5 million in 1996. Michigan, Minnesota, and Wisconsin pulpwood production is shown by county and species group.

I studied reproduction of the Barn Owl (Tyto alba) in northern Utah from 1977 through 1996 documenting 451 nesting attempts by at least 500 individuals. The study site was a narrow valley bounded by the Wasatch Mountains and the Great Salt Lake. This area was formerly shrubsteppe desert, but that community is now entirely supplanted by irrigated agriculture and urban development.