Treesearch

The forestry profession has the responsibility of managing forests for all of their values. In the past, this has usually not been done. Often, timber has been the only value considered. The emphasis has not been on practices that combine other values with timber production. Such forestry practices must consider forest types and conditions, site quality and characteristics, and the long time needs of the people. This will require a broad concept of economics and based on all values. These would include watershed protection, erosion control, recreation, aesthetics, wildlife habitat,...

Changes in basal area, density and average diameter were examined on a 156,000-acre privately owned oak-hickory forest in the Missouri Ozarks. The forest has been managed since 1954 using the single-tree selection method. Trees greater than five inches dbh were monitored on 486 one-fifth-acre permanent plots at five year intervals from 1962 through 1992. Seven species/species groups accounted for approximately 90% of both basal area and density throughout this 30-year period. Average basal area increased by 48% and average density by 69% during the study period. Quadratic mean diameter...

Studies of advance regeneration and post-disturbance regeneration adequacy were conducted during the recent USDA Forest Service inventory of forest resources in Pennsylvania. The first study examined advance tree-seedling regeneration in stands where stocking levels would suggest that advance regeneration should be abundant. A range of metrics was used to describe regeneration adequacy. Findings indicate that advance regeneration is generally lacking in the State. The results ranged from only 4% to 40% of the sample locations being adequately stocked (based on the most and least stringent...

Three hundred and thirty-two plots have been sampled on the Wayne National Forest of southeastern Ohio, for the purpose of developing an ecological classification system (ECS). The ECS will be based on the herbaceous and woody vegetation, soils and topography of mature (80-140 year-old), relatively-undisturbed forests. Species diversity changes little across this landscape. Forty-eight woody tree species were identified among all plots and species richness (R) varied from two to thirteen on individual plots. Although variable within landform type, R varied similarly across landform type,...

Effects of canopy opening and white-tailed deer on ground level vegetation are being assessed in south-central Pennsylvania. Herbaceous plants and woody seedlings are being monitored in three unevenaged, mixed oak woodlots at Gettysburg National Military Park. Canopy opening levels on 0.20 ha treatment units were closed (~100% canopy), small (50-60% canopy) and large (0% canopy). Number of white-tailed deer during April have averaged about 0.40 deer per ha since 1992. Overstory treatments were conducted in March 1993. Fences to exclude deer were installed on one-half of the understory...

The forests of the Allegheny Plateau section of northwestern Pennsylvania have been severely impacted for more than 70 years by selective browsing by white-tailed deer (Odocoileus virginianus). Historical and ecological interactions of deer and the forest ecosystem in this region from pre-settlement times to the present are presented based on data from the Allegheny National Forest area. The data suggest that deer impacts on forested ecosystems can be controlled through a combination of increased, sustained deer harvests and increased forage production through timber harvesting.

Carbon (C) and nitrogen (N) storage capacities are critical issues facing forest ecosystem management in the face of potential global climate change. The amount of C sequestered by forest ecosystems can be a significant sink for increasing atmospheric CO2 levels. N availability can interact with other environmental factors such as water availability or temperature to control potential forest productivity. This in turn, may determine the amount of C that can be sequestered in forest ecosystems. This study was designed to quantify C and N pools in oak-hickory dominated forest stands of...

This study evaluates forest herb-layer sensitivity to annual-scale environmental fluctuation. Specific objectives were to determine the between-year variation in herb-layer community biomass, and to contrast and evaluate the temporal stability of spatial relationships in herb-layer community structure and composition between successive years. Aboveground dry weights of herbs and of woody species 4.5 cm dbh were estimated in June of 1988 and 1989 in 13 ecologically analogous, oak-dominated stands along a 170-km east-west transect in north-central Pennsylvania. An approximately 50% reduction...

The forest floor plays a major role in the storage and recycling of nutrients which, in turn, are important in maintaining the growth and productivity of forest ecosystems. The development of forest floor organic layers as influenced by litter quality and site quality is unclear. Previous studies in this lab have shown that the size and distribution of available nutrient pools in the forest floor fractions are related to site productivity. The objectives of this project are to: (1) determine the biomass distributions of forest floor organic fractions across oak-hickory forest sites along a...

Sugar maple (Acer saccharum Marsh) is an important commercial tree species of the central hardwood region which is valued for its wood and maple sugar products. High elevation sugar maple stands in northcentral Pennsylvania have been in serious decline for about the last 15 years with more than 1,200 hectares of maple forest affected. The decline appears to be largely irreversible, leading to the death of the affected trees. Stands at lower slope positions remain generally healthy. The objective of this study was to investigate the role of soil conditions in causing sugar maple decline by...