Treesearch

Montane forests in the High Tatra Mountains are exposed to high ambient ozone (O3) concentrations that may adversely affect the physiological processes and health of plants. This study presents the modelled results of the phytotoxic ozone dose (POD) for dwarf mountain pine (P. mugo) in 2016. POD metrics were calculated using the deposition model DO3SE, with O3 concentration and meteorological data measured in three altitudinal zones. In addition, maximal stomatal conductance (Gmax) derived from gasometric field measurement in local conditions was included in the model. Field measurements...

Tall trees and vertical forest structure are associated with increased productivity, biomass and wildlife habitat quality. While climate has been widely hypothesized to control forest structure at broad scales, other variables could be key at fine scales, and are associated with forest management. In this study we identify the environmental conditions (climate, topography, soils) associated with increased tree height across spatial scales using airborne Light Detection and Ranging (LiDAR) data to measure canopy height. The study was conducted over a large elevational gradient from 200 to...

Knowledge of how tree groups and gaps are formed and maintained in frequent-fire forests is key to managing for heterogeneous and resilient forest conditions. This research quantifies changes in tree group and gap spatial structure and abundance of ponderosa pine (Pinus ponderosa) and California black oak (Quercus kelloggii) with stand development after wildfires in 1990 and 1994 in an old-growth forest in the Ishi Wilderness, southern Cascades, California. Forest demography and tree group and gap structure were quantified by measuring, mapping, and aging trees in six 1-ha permanent plots...

Residential development is one of the most intensive and widespread land uses in the United States, with substantial environmental impacts, including changes in forest cover. However, the relationships between forest cover and residential development are complex. Contemporary forest cover reflects multiple factors, including housing density, time since development, historical land cover, and land management since development. We investigated how forest cover varies with housing density, housing age, and household income over a range of development intensities, in six ecoregions within New...

Population responses to environmental extremes often dictate the bounds to species' distributions. However, population dynamics at, or near, those range limits may also be affected by sublethal effects. We exposed late instars and pupae of an invasive leafroller, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), to cold temperatures and measured the effects of exposure on subsequent survivorship, development, and reproduction. Cold temperature was applied as acute exposure to –10 °C (a low, but not immediately lethal temperature for this species) or the onset of freezing (the peak...

Coptotermes formosanus, known in its native China as the ‘House White Ant’, was introduced to the southeast USA likely in the 1950s, where it is known as the Formosan subterranean termite. In the USA it is best known as a pest of buildings in urban areas, however C. formosanus also attacks live trees along streets and in urban parks, suggesting it may be able to invade forests in the USA. A survey of 113 forest patches around Charleston South Carolina and New Orleans Louisiana, where C. formosanus was first recorded, found that 37% and 52%, respectively, were infested. Resistograph...

Using natural disturbance as a guide to management is an approach to develop resilience, maintain or restore natural processes, and sustain ecosystem goods and service. Here, we compare features of mounds resulting from tree uprooting, tree structure and composition, and browsing in recent 10–12-year-old moderate-severity wind disturbance events and reference stands in old hemlock– (Tsuga canadensis–) hardwood forests in Wisconsin, USA. Compared to reference stands, recent, partial blowdown stands had reduced overstory tree density and canopy heights, and more large gaps, coarse woody...

Ecological restoration projects that include reforestation require that land managers select appropriate source of seeds for long-term persistence. In California, the standard approach for making this choice is based on seed zone and elevational band, both geographically-based measures. However, given the pace of contemporary climate change, populations previously adapted to local conditions may become increasingly mismatched to the changes in climate. If there is a lag in adaptation, current seed zones which assume local is best, would be less useful for reforestation guidelines. Here we...

Winter walks around my Portland neighborhood remind me how fungi are exquisitely tuned in to environmental factors including short term weather and seasonal change. Most of this past growing season has been especially rich in fungal abundance and diversity. The same cold snaps that signal autumnal senescence and fall foliage coloration in broadleaved trees also seem to stimulate a last wave of fruiting by a range of macro-fungi. As the northern forest moves into the more muted tones of late fall and the monochrome of winter, I like to imagine that the fungi know that they have a limited...

Forest managers and policymakers rely heavily on broad-scale spatial information to better channel scarce funds to address important issues, especially those related to restoration. The abundance of white-tailed deer (Odocoileus virginianus) and their impact on young-forest habitat (YFH) establishment and development qualifies as such an issue. Restoring broadleaf deciduous forests in the Midwest and Northeast has become nearly impossible in many areas, because deer are devouring the next generation of trees. With YFH increasingly rare and invasive plants and pests expanding, foresters are...