We examined bird-habitat relationships within and across a range of aspen habitats in four major watersheds in the eastern Sierra Nevada mountains of California and Nevada to identify habitat features of importance to aspen-breeding birds. Using point counts and vegetation assessments from 462 individual stations between 2001 and 2003 allowed us to investigate important habitat features at wate...

This research aims at developing anoperator training simulator (OTS) using AspenOTS Frameworkfor fatty acid methyl ester (FAME) production plant. All over the world, there is an increasing interest towards the use of vegetable oils in much desired ecofriendly biodiesel production. In view of environmental concerns due to high polluting nature of fossil fuels and also because of the limited avai...

Aspen has been an ecologically important, though relatively minor, component of the Lake States (Michigan, Wisconsin, and Minnesota) forests for millennia. General Land Office records from the 1800s indicate that aspen comprised a small fraction of the region’s eastern forests, but was more extensive on the western edge. Then Euro-American settlement in the 1800s brought land clearing, timber h...

The Central Plains of Western Canada comprise the Prairies Ecozone and the Boreal Plains Ecozone. The former has the most grasslands and is divided into seven ecoregions: Mixed Grassland, Cypress Upland, Moist Mixed Grassland, and Fescue Grassland in southern Alberta and Saskatchewan; Aspen Parkland, which extends in an arc from central Alberta and Saskatchewan southeast to southwestern Manitob...

—Widespread establishment of seedling aspen (Populus tremuloides) occurred in Yellowstone National Park (YNP) following the extensive1988 fires. Aspen stands occupy ;2% of YNP and aspen stems are intensively browsed by native ungulates. Chemical composition, especially secondary compounds, may influence levels of herbivory and, hence, survival of aspen, but concentrations of such compounds in a...

As human activity continues to increase CO2 and O3, broad expanses of north temperate forests will be simultaneously exposed to elevated concentrations of these trace gases. Although both CO2 and O3 are potent modifiers of plant growth, we do not understand the extent to which they alter competition for limiting soil nutrients, like nitrogen (N). We quantified the acquisition of soil N in two 8...

In Rocky Mountain National Park (RMNP), aspen (Populus tremuloides Michx.) has been observed to be declining on elk (Cervus elaphus nelsoni) winter range for many decades. To support elk management decisions, the SAVANNA ecosystem model was adapted to explore interactions between elk herbivory and aspen dynamics. The simulated probability of successful vegetative regeneration for senescent aspe...

Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlak...

Current understanding of aspen fire ecology in western North America includes the paradoxical characterization that aspen-dominated stands, although often regenerated following fire, are “fire-proof”. We tested this idea by predicting potential fire behavior across a gradient of aspen dominance in northern Utah using the Forest Vegetation Simulator and the Fire and Fuels Extension. The wind spe...

Understanding the responses of species and ecosystems to human-induced global environmental change has become a high research priority. The main aim of this thesis was to investigate how certain environmental factors that relate to global change affect European aspen (Populus tremula), a keystone species in boreal forests, and hybrid aspen (P. tremula × P. tremuloides), cultivated in commercial...