Treesearch

Based on data from Illinois, Indiana, and Ohio following the 1988 drought, acid deposition does not increase the susceptibility of oak trees to drought stress.

Modelling of erosion and deposition in complex terrain within a geographical information system (GIS) requires a high resolution digital elevation model (DEM), reliable estimation of topographic parameters, and formulation of erosion models adequate for digital representation of spatially distributed parameters. Regularized spline with tension was integrated within a GIS for computation of DEMs and topographic parameters from digitized contours or other point elevation data. For construction of flow lines and computation of upslope contributing areas an algorithm based on vector-grid...

Changes in the large-scale mean thermal structure of the atmosphere have the potential for affecting the dynamics of the atmosphere across the entire spectrum of scales that govern atmospheric processes. Inherent in these changes are interactions among the scales that could change, resulting in an alteration in the frequency of regional weather systems conducive to fire occurrence. In support of the Northern Stations Global Change Research Program, we have designed a research program to examine the interactions of large-scale atmospheric processes with regional fire-weather systems. This...

Dieback and growth decline of red spruce (Picea rubens) in the eastern U.S. coincides with the period of acidic deposition, and has led to much speculation as to whether this decline is caused by decreased root-available Ca in the soil.

We studied the effects of acidification on leaf litter decomposition in six headwater streams in the Monongahela National Forest. These streams differed in underlying geology and mean baseflow pH (3.99, 4.24, 6.13, 6.47, 6.59, and 7.52). We placed 10-gram leaf packs of white oak, red maple, and yellow poplar in each stream, and retrieved them after two days, two weeks, and then at 4-week intervals from November 1993 to February 1994. Leaf packs were analyzed to determine changes through time in leaf decay rate, invertebrate composition, density, and biomass, and microbial biomass (ATP...

Peatlands in the northern hemisphere (346 x 108 ha) store large amounts of carbon; estimated at 455 petagrams (Pg) (=1015) (Gorham 1991).

The Charles Lathrop Pack Demonstration Forest, Warrensburg, New York, has been the site of long-term forest fertilization and biogeochemical ecosystem research for over 50 years.

This study quantified soil nutrient status and N mineralization/nitrification potentials in soils of oak-dominated, unmanaged forest stands in seven USDA Forest Service experimental forests (EF) ranging along a historical and current acidic deposition gradient from southern Illinois to central West Virginia.

The cause or causes of recently observed mortality and changes in forest composition in eastern mixed-oak forests has been a controversial topic.

In 1957-1960, R. O. Curtis and B. W. Post surveyed 81 even aged (45-90 y old) northern hardwood stands on acid till soils over the length of Vermont's Green Mountains. The purpose of the original study was to determine predictive relationships between site index and site characteristics, including latitude, elevation, soil drainage class, soil organic matter content and soil nutrients. The sites were not randomly selected in the 1950s. Rather, they were chosen to represent a range of stand ages and the range of environmental conditions associated with northern hardwood forests growing on...