Treesearch

Several aspects of wildland fire are moderated by site- and landscape-level vegetation changes caused by previous fire, thereby creating a dynamic where one fire exerts a regulatory control on subsequent fire. For example, wildland fire has been shown to regulate the size and severity of subsequent fire. However, wildland fire has the potential to influence other properties of subsequent fire. One of those properties - the extent to which a previous wildland fire inhibits new fires from igniting and spreading within its perimeter - is the focus of our study. In four large wilderness study...

To investigate natural enemies of emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), in northeastern China, we conducted field surveys of ash (Fraxinus Linnaeus (Oleaceae)) trees in semi-natural forests and plantations at variable EAB densities from 2008 to 2013. Our surveys revealed a complex of natural enemies including eight hymenopteran parasitoids and two apparently parasitic Coleoptera, woodpeckers, and several undetermined mortality factors. Parasitoid complex abundance and its contribution to EAB mortality varied with the time of year, type of ash...

We contend that traditional approaches to forest conservation and management will be inadequate given the predicted scale of social-economic and biophysical changes in the 21st century. New approaches, focused on anticipating and guiding ecological responses to change, are urgently needed to ensure the full value of forest ecosystem services for future generations. These approaches acknowledge that change is inevitable and sometimes irreversible, and that maintenance of ecosystem services depends in part on novel ecosystems, i.e., species combinations with no analog in the past. We propose...

Peatlands are a subset of wetlands that have accumulated significant amounts of soil organic matter. Soils of peatlands are colloquially known as peat, with mucks referring to peats that are decomposed to the point that the original plant remains are altered beyond recognition (Chapter 6, SSSA 2008). Generally, soils with a surface organic layer >40 cm thick have been classified as Histosols in the U.S. soil classification system—Soil Taxonomy (Soil Survey Staff 2014). Permafrost-affected organic soils are classified as the Histels suborder in the Gelisols order (Soil Survey Staff 2014)....

These proceedings report invited presentations and contributions to the 2015 Forest Inventory and Analysis (FIA) Symposium, which was hosted by the Research and Development branch of the U.S. Forest Service. As the only comprehensive and continuous census of the forests in the United States, FIA provides strategic information needed to evaluate sustainability of current forest management practices across all ownerships. Papers and abstracts included in the publication have been sorted into general topic areas, including forest carbon accounting, change detection, and techniques development....

The Maximal Covering Location Problem (MCLP) is a classic model from the location science literature which has found wide application. One important application is to a fundamental problem in conservation biology, the Maximum Covering Species Problem (MCSP), which identifies land parcels to protect to maximize the number of species represented in the selected sites. We trace the evolution of the MCSP from the MCLP, review extensions, and offer suggestions for new lines of research related to the MCSP.

Creating, restoring, and sustaining forests in urban areas are complicated by habitat fragmentation, invasive species, and degraded soils. Although there is some research on the outcomes of urban reforestation plantings during the first 5 years, there is little research on longer term outcomes. Here, we compare the successional trajectories of restored and unrestored forest sites 20 years after initiating restoration. The sites are located within the Rodman's Neck area of Pelham Bay Park, in the northeast corner of the Bronx in New York City (NYC), U.S.A. Compared with unrestored sites, we...

The effects of thermal radiation and moisture content on the pyrolysis and gas phase ignition of a solid fuel element containing high moisture content were investigated using the coupled Gpyro3D/FDS models. The solid fuel has dimensions of a typical Arctostaphylos glandulosa leaf which is modeled as thin cellulose subjected to radiative heating on one side. We incorporated a five-step extended Broido-Shafizadeh reaction model for thermal degradation, moisture evaporation, and pyrolysis of cellulose in Gpyro3D. The solid-phase model was successfully validated against published data....

Previous studies at the scale of a city have shown that surface soil nutrients, pH, and soil organic matter (SOM) can vary by land cover, land use, and management. This study was conducted in Baltimore County, Maryland, to quantify the differences in characteristics of soil in a residential neighborhood and adjacent forest patch sampling at a fine scale. The first objective was to compare soil characteristics in a residential neighborhood among ecotope types of forest, lawn, and planting beds that were underlain by the same parent material and thus only differed in plant cover. Another...

To increase the availability of improved, adapted white oak (Quercus alba L.) for midwestern United States landowners, we analyzed data from three 23-year-old provenance/progeny tests of 70 open-pollinated progenies from 17 provenances. Our goal was to estimate the heritability of height growth and range of adaptation and ultimately to determine the value of converting the sites to seed orchards. Tree growth was marked by positive spatial autocorrelation (SA) for height in all three test sites despite differences in management and mortality. Microsites with the highest SA changed little...