Treesearch

Even-aged silvicultural methods have been successfully used to manage longleaf pine (Pinus palustris Mill.) forests for wood production; however, successful use of uneven-aged methods to manage this ecosystem is less well documented. In this study, the effects of varying levels of residual basal area (RBA) (9.2, 13.8, and 18.4 m2·ha-1) on longleaf pine germination and establishment under selection silviculture marked using the Proportional-B method were observed. In addition to RBA, photosynthetically active radiation (PAR) was measured, and the relationships between light penetration,...

The goal of this study was to test the sensitivity of water yield to forest thinning and other forest management/disturbances and climate across the conterminous United States (CONUS). Leaf area index (LAI) was selected as a key parameter linking changes in forest ecosystem structure and functions. We used the Water Supply Stress Index model to examine water yield response under 18 scenarios that combine hypothetical LAI changes (+10%, ±20%,
50%, and
80%), uniform increases in temperature (+1 °C and +2 °C) and precipitation change (±10%), and four climate change scenarios projected by...

The southeastern United States is among the most productive forested areas in the world. Four endemic southern pine species – loblolly, longleaf, shortleaf, and slash - contribute significantly to the economic and ecological values in the region. A recently described phenomenon known as Southern Pine Decline (SPD) has been reported as having widespread impact in the southern pine region, particularly on loblolly pine. Root-feeding weevils and their associated fungi have been suggested as causal agents, even though literature and empirical research suggests that they are secondary insects...

This study examines the distributional equity of urban tree canopy (UTC) cover for Baltimore, MD, Los Angeles, CA, New York, NY, Philadelphia, PA, Raleigh, NC, Sacramento, CA, and Washington, D.C. using high spatial resolution land cover data and census data. Data are analyzed at the Census Block Group levels using Spearman’s correlation, ordinary least squares regression (OLS), and a spatial autoregressive model (SAR). Across all cities there is a strong positive correlation between UTC cover and median household income. Negative correlations between race and UTC cover exist in bivariate...

Recent years have seen growing interest within the United States fire management community in exploring alternatives to the standard approach of evacuating entire populations that are threatened by a wildfire. There has been particular interest in what can be learned from the Australian approach, whereby residents choose whether or not to evacuate under the 'prepare, stay and defend or leave early' approach, also called Stay or Go. Given these developments, it is useful to understand what elements are taken into consideration by those who would be most affected by a new approach when they...

Prescribed burning is the major viable option that land managers have for reducing hazardous fuels and ensuring the regeneration of fire-dependent species in a cost-effective manner in Pine Barren ecosystems. Fuels management activities are directly linked to carbon (C) storage and rates of C sequestration by forests. To evaluate the effects of prescribed burning on forest C dynamics, we quantified consumption and accumulation of the forest floor and understory vegetation and measured net CO2 exchange in upland forest stands in the New Jersey Pinelands burned with prescribed fires....

Ecologists are increasingly tackling questions that require significant infrastucture, large experiments, networks of observations, and complex data and computation. Key hypotheses in ecology increasingly require more investment, and larger data sets to be tested than can be collected by a single investigator’s or s group of investigator’s labs, sustained for longer than a typical grant. Largescale projects are expensive, so their scientific return on the investment has to justify the opportunity cost-the science foregone because resources were expended on a large project rather than...

Pine-oak ecosystems are globally distributed even though differences in anatomy and leaf habit between many co-occurring oaks and pines suggest different strategies for resource use, efficiency and stomatal behavior. The New Jersey Pinelands contain sandy soils with low water- and nutrient-holding capacity providing an opportunity to examine trade-offs in resource uptake and efficiency. Therefore, we compared resource use in terms of transpiration rates and leaf nitrogen content and resource-use efficiency including water-use efficiency (WUE) via gas exchange and leaf carbon isotopes and...

The density and composition of regeneration drives future forest character for forests in need of replacement. Forested ecosystems face numerous regeneration stressors including invasive plants, insects and diseases, herbivory, lack of management, and climate change. As stands that make up these systems age, it is imperative to track the viability of forest reproduction. The information required for understanding the complexity of forest dynamics during the stand establishment stage has been lacking in our Nation's forest inventory. This poses a particular problem for analysts working with...

Interactions between ecological disturbances have the potential to alter other disturbances and their associated regimes, such as the likelihood, severity, and extent of events. The influence of exposure to wind and yellow cedar decline on the landslide regime of Alaskan temperate rainforests was explored using presence-only modeling techniques. The wind regime was found to be a significant influence on the spatial distribution of landslide events. This effect was mediated by slope, with little interactive effects at low angles and stronger influences on steeper slopes. Mechanistically,...