Treesearch

The structure and function of terrestrial ecosystemsare maintained by processes that vary with temporal and spatial scale. This study examined temporal and spatial patterns of net nitrogen (N) mineralization and nitrification in mineral soil of three watersheds at the Fernow Experimental Forest, WV: 2 untreated watersheds and 1 watershed receiving aerial applications of N over a 25-year period. Soil was sampled to 5 cm from each of seven plots per watershed and placed in two polyethylene bags—one bag brought to the laboratory for extraction/analysis, and the other bag incubated in situ at...

Green spaces embedded within the urban matrix, particularly residential yards, could mitigate negative aspects of urban development and provide pollinator habitat. Lawns represent a dominant green space, and their management consists of frequent mowing to inhibit the growth of ostensibly “weedy” species (e.g., dandelions and clover). Since widespread population declines of bees and other pollinators from habitat loss are a growing concern, these spontaneous flowers could provide pollen and nectar sources throughout the growing season. We experimentally tested whether different lawn mowing...

The wildland-urban interface (WUI) is the area where houses and wildland vegetation meet or intermingle, and where wildfire problems are most pronounced. Here we report that the WUI in the United States grew rapidly from 1990 to 2010 in terms of both number of new houses (from 30.8 to 43.4 million; 41% growth) and land area (from 581,000 to 770,000 km2; 33% growth), making it the fastest-growing land use type in the conterminous United States. The vast majority of new WUI areas were the result of new housing (97%), not related to an increase in wildland vegetation. Within the perimeter of...

An improved understanding of atmospheric perturbations within and above a forest during a wildland fire has relevance to many aspects of wildland fires including fire spread, smoke transport and dispersion, and tree mortality. In this study, the ARPS-CANOPY model, a version of the Advanced Regional Prediction System (ARPS) model with a canopy parameterization, is utilized in a series of idealized numerical experiments to investigate the influence of vertical canopy structure on the atmospheric response to a stationary sensible heat flux at the ground ("fire heat flux"), broadly consistent...

Restoring the estimated 1 billion hectares of degraded forests must consider future climate accompanied by novel ecosystems. Transformational restoration can play a key role in adaptation to climate change but it is conceptually the most divergent from contemporary approaches favoring native species and natural disturbance regimes. Here, we review concepts of novelty in ecosystems with examples of emergent/neonative and designed novel ecosystems, with application to transformational restoration. Danish forests have a high degree of novelty and provide a realistic context for discussing...

The aim of this study was to quantify street tree population dynamics in the city of Claremont, CA. A repeated measures survey (2000 and 2014) based on a stratified random sampling approach across size classes and for the most abundant 21 species was analyzed to calculate removal, growth, and replacement planting rates. Demographic rates were estimated using a hierarchical Bayesian framework. The community-level (all species) median growth rate was 1.41% per year (95% CI: 1.21–1.65%) with Pinus brutia and Pistacia chinensis growing significantly faster than the community-level median. The...

An effective management plan for invasive herb populations must consider the potential for regeneration from the soil seedbank. To test chis potential, we examined two species, Japanese scilcgrass and garlic mustard, at deciduous forest sites in southeastern Ohio. Seeds were buried in nylon mesh bags and recovered at regular intervals over 24 mo. Recovered seeds were tested for germination and viability. Burial was replicated on north- and south-facing slopes to test for environmental control of dormancy state. Stilcgrass seeds experienced severe mortality in the soil, rarely surviving the...

This update provides an overview of forest resources in Illinois following an inventory by the USDA Forest Service, Forest Inventory and Analysis program, Northern Research Station. Estimates are derived from field data collected using an annualized sample design. Current variable estimates such as area and volume are based on 5,994 (1,046 forested) plots measured in 2011–2017. Change variables such as net growth, removals, and mortality are based on 5,914 (964 forested) plots measured in 2005–2011 and resampled in 2011–2017. See Bechtold and Patterson (2005), O'Connell et al. (2014),...

Regional (climate/soils) and local (aspect) physiography determine plant community composition. However, changes in initial floristic composition after a disturbance may be severe enough to alter the successional trajectory predicted by physiography. We addressed the question of which is more important, disturbance or physiography, in determining vegetation composition and the consequent successional trajectory. We evaluated understory vegetation of forest communities exposed to four disturbance types (control, single burn, diameter-limit cut, and first-removal shelterwood) 2–5 yr postdistu...

Resource managers have long mapped biophysical forest data. Often lacking, however, is relevant social science data for understanding the variety of human needs a given landscape fulfills. For nearly a decade, Lee Cerveny has been exploring how to provide this data on public lands around the Pacific Northwest. Cerveny is a research social scientist with the Pacific Northwest Research Station. In collaboration with several colleagues, she is using in-person mapping exercises and workshops with graphic information system software to capture social values, ecosystem benefits, and resource...