Treesearch

Forest management activities can reduce ectomycorrhizal fungus diversity and forest regeneration success. We examine contrasts in structural retention as they affect sporocarp production of ectomycorrhizal fungi (EMF)--functional guild of organisms well suited as indicators of disturbance effects on below-ground ecosystems. Our results are from an experiment that tests the biodiversity assumptions behind current guidelines for ecosystem management. Ours is the first study complete with pre-treatment data that examines the effects of silvicultural manipulations on both epigeous (mushroom)...

Elk (Cervus elaphus) populations in western North America have been intensively managed for the past century. The species' popular appeal as an animal for hunting and viewing, and its potential to damage agricultural crops and to compete with livestock make it a species that is closely scrutinized by managers and many public interest groups. Today, elk continue to have significant ecological, cultural and economic values. For example, the species provides substantial revenue for rural communities from hunting and viewing. Since the 1960s, elk in some areas of the western United States...

We studied habitat relations of the Prince of Wales flying squirrel (Glaucomys sabrinus griseifrons), an endemic of the temperate, coniferous rainforest of southeastern Alaska, because of concerns over population viability from extensive clear-cut logging in the region. We used stepwise logistic regression to examine relationships between microhabitat use (i.e., captures among traps spaced at 40-m intervals) and 26 vegetative and structural habitat features measured in plots centered on trap stations. Seasonal (spring, autumn) models were created for two old-growth forest types: upland,...

The extent of water uptake by lateral roots of savanna trees in the Brazilian highlands was measured by irrigating two 2 by 2 m plots with deuterium-enriched water and assaying for the abundance of deuterium in stem water from trees inside and at several distances from the irrigation plots. Stem water of trees inside the irrigation plots was highly enriched compared to that of control trees, whereas stem water of trees just outside the plot was only slightly enriched compared with that from control trees. Therefore, bulk water uptake in the savanna trees studied occurred in a horizontally...

Fourteen authors, ranging from transportation specialists to ecologists, have collaborated to write this very useful compendium describing the newly minted discipline of "road ecology." The authors state that road ecology "uses the science of ecology and landscape ecology to explore, understand, and address the interactions of roads and vehicles with their surrounding environment." The book is not aimed at ecologists; rather, the book's intended primary audience is people associated with transportation, including engineers, planners, environmental specialists, economists, and social...

Previous studies of model performance at varying resolutions have focused on winter storms or isolated convective events. Little attention has been given to the static high pressure situations that may lead to severe wildfire outbreaks. This study focuses on such an event so as to evaluate the value of increased model resolution for prediction of fire danger. The results are intended to lay the groundwork for using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) as input to the National Fire Danger Rating System to provide...

Breast-high stem sections were sampled from 56 western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees growing in 15 plots representing a wide range of tree and site conditions in northwestern Oregon. Growth and wood density traits of individual rings were measured via X-ray densitometry, and relationships of ring density and its components to age and growth rate were analyzed. Ring density was highest (0.49 g/cm3) near the pith, declined to 0.40 g/cm3 at age 10, remained stable to about age 25, and then increased gradually and remained between 0.43 and 0.44 g/cm3 from age 38 to 45 and...

This work was undertaken under a joint fire science project "Assessing the need, costs, and potential benefits of prescribed fire and mechanical treatments to reduce fire hazard." This paper compares the future mix of timber projects under two treatment scenarios for New Mexico.We developed and demonstrated an analytical method that uses readily available tools to evaluate pre- and posttreatment stand conditions; size, species, and volume of merchantable wood removed during thinnings; size and volume of submerchantable wood cut during treatments; and financial returns of prescriptions that...

Net canopy interception (Inet) during rainfall in an old-growth Douglas-fir-western hemlock ecosystem was 22.8 and 25.0% of the gross rainfall (PG) for 1999 and 2000, respectively. The average direct throughfall proportion (p) and canopy storage capacity (S) derived from high-temporal resolution throughfall measurements were 0.36 and 3.3 mm, respectively. Derived values of S were very sensitive to the estimated evaporation during canopy wetting (Iw). Evaporation during wetting was typically small due to low vapor pressure deficits that usually occur at the start of an event, therefore I,...

The Biscuit Fire in southwestern Oregon was one of the largest and most costly in recent history, burning over 499,000 acres and costing over 150 million dollars in suppression efforts. This study uses prefire resource information in conjunction with postfire burn severity to generate statistically reliable prefire resource estimates for the land within the Biscuit Fire perimeter. Resource parameters such timber volume, down woody material, area by forest type, and understory cover compared between burn severity classes.