Treesearch

Population connectivity is mediated by the movement of organisms or propagules through landscapes. However, little is known about how variation in the pattern of landscape mosaics affects the detectability of landscape genetic relationships. The goal of this paper is to explore the impacts of limiting factors on landscape genetic processes using simulation modeling. We used spatially explicit, individual-based simulation modeling to quantify the effects of habitat area, fragmentation and the contrast in resistance between habitat and non-habitat on the apparent strength and statistical...

This paper summarizes the application of a land classification system developed by the senior author to the Standing Stone State Forest and State Park (SSSF&SP) on the Eastern Highland Rim. Landtypes are the most detailed level in the hierarchical system and represent distinct units of the landscape (mapped at a scale of 1:24,000) as defined by climate, geology, soils, topography, and vegetation. The area is highly dissected with local relief of about 1,000 feet. Mississippian and Ordovician strata are essentially level bedded; defining elevations were assigned. Suites of soils are common...

Width reduction in growth rings in shortleaf pine (Pinus echinata Mill.) following glaze ice conditions produces a characteristic pattern dependent on live-crown ratio and extent of crown loss. Ring widths of 133 trees for 3 years preceding and 7 years following the December 2000 ice storm (Bragg and others 2002) in western Arkansas and eastern Oklahoma were cross-dated to detect missing rings, then measured under a 32X microscope. Data from undamaged trees was detrended using a logarithmic decay function to identify the climate signal, which was then incorporated into the model. Ring...

When used as a measure of relative density, Reineke’s stand density index (SDI) can be made unitless by relating the current SDI to a standard density but when used as a quantitative measure of stand density SDI is not unitless. Reineke’s SDI relates the current stand density to an equivalent number of trees per unit area in a stand with a quadratic mean diameter (Dq) of either 10 inches (English units) or 25.4 cm (metric units). Thus, when used as a quantitative measure, SDI is in fact unit dependent on two levels, one is whether English or metric units are used, and the second is whether...

Fuel distribution in the Southern Appalachian Mountain region was measured on 1,008 study plots that were stratified by topographic position (aspect and slope position). Few fuel differences occurred among topographic positions indicating that fuel accumulation is no greater on highly productive sites than on less productive sites. Litter was slightly higher on undisturbed upper slopes than on lower slopes but woody fuels showed no significant differences. Rhododendron (Rhododendron spp.) and mountain laurel (Kalmia latifolia) were less common than expected occurring on 25 and 42 percent...

Understanding the main and interactive effects of chronically altered resource availability and disturbance on phosphorus (P) availability is increasingly important in light of the rapid pace at which human activities are altering these processes and potentially introducing P limitation. We measured P pools and fluxes in eighteen mixed forest stands at three elevations (low, mid, high) subjected to increasing atmospheric N deposition, where hemlock (Tsuga canadensis) was absent or declining due to infestation by the exotic hemlock woolly adelgid (Adelges tsugae). While total soil P was...

Sensor networks are revolutionizing environmental monitoring by producing massive quantities of data that are being made publically available in near real time. These data streams pose a challenge for ecologists because traditional approaches to quality assurance and quality control are no longer practical when confronted with the size of these data sets and the demands of real-time processing. Automated methods for rapidly identifying and (ideally) correcting problematic data are essential. However, advances in sensor hardware have outpaced those in software, creating a need for tools to...

Land managers throughout the Southeast are interested in restoring the longleaf pine (Pinus palustris Mill.) ecosystem, due in part to its value as habitat for the endangered red-cockaded woodpecker (Picoides borealis). In 2003, we established a study at Camp Lejeune, NC, to determine the effects of common site preparation treatments (mounding, bedding, herbicide, and chopping) on longleaf pine restoration on wet sites. We monitored mortality and measured root-collar diameter and height after three growing seasons. Although we found early increases in seedling growth in response to site...

Preliminary results are given for development of an eastern redcedar (Juniperus virginiana) cubic-volume equation based on measurements of redcedar sample tree stem volume using dendrometry with Monte Carlo integration. Monte Carlo integration techniques can be used to provide unbiased estimates of stem cubic-foot volume based on upper stem diameter measurements obtained at randomly selected stem heights. Monte Carlo integration with importance sampling and antithetic variates was used to obtain sample tree volume estimates in this study. Importance sampling is a variance reduction...

Five years after a Southern Appalachian cove was regenerated, vegetation was dominated by a dense stand of yellow-poplar (Liriodendron tulipifera), which averaged 9,181±13,042 stems per acre, and other mesophytic hardwood seedlings and saplings. The stand was prescribed burned during late spring to improve habitat for turkey by reducing density of saplings to stimulate greater production of grasses and herbs. The prescribed fire completely killed about 69 percent of the saplings; the others were topkilled and produced basal sprouts that reclaimed much of the canopy growing space after one...