In this thesis, we first examine the principle hypotheses behind the improved exotic growth of select timber species, and the evidence for each, with special focus on studies which examine growth between several ranges of a species. We find that literature suggests environmental factors directly tied to net primary production...
Early establishment of competing vegetation often presents an obstacle to the success of planted white spruce (Picea glauca (Moench) Voss) seedlings. We followed growth and development of white spruce and associated vegetation for up to 17 years in Alaska's boreal forests to quantify roles of overtopping plant cover in suppressing...
Temperate coniferous forests, such as those that cover vast areas of the western US and Canada, have evolved to depend on cycles of disturbance for succession of species and overall ecosystem maintenance. Many of these forest systems are managed, often for timber production, where disturbances are of anthropogenic origin and...
Fuel accumulation and climate shifts are predicted to increase the frequency of high-severity fires in pon-derosa pine (Pinus ponderosa) forests of central Oregon. The combustion of fuels containing large downedwood can result in intense soil heating, alteration of soil properties, and mortality of microbes. Previousstudies show ectomycorrhizal fungi (EMF) improve...
Measurements of physical tree crown dimensions were of subjective character in the past, even though they can be considered important for the management of many silvicultural operations, such as timing of thinning operations. In our study we investigated if and how measures of physical crown dimensions of trees differed when...
Wildfires can create alternative pathways for forest development, and wildfires have expanded in size, frequency, intensity, and severity across the western United States. The purpose of this paper is to compare forest development of a mature Douglas-fir forest in western Oregon across fire severities. Postburn field measurements were collected in...
The intensity and scale of wildfires has increased throughout the Pacific Northwest in recent decades, especially within the last decade, destroying vast amounts of valuable resources and assets. This trend is predicted to remain or even magnify due climate change, growing population, increased housing density. Furthermore, the associated stress of...
Quaking aspen, Populus tremuloides, has experienced severe declines in recent years in part due to the effects of changing climate and extreme drought. As the dominant deciduous tree in Western North American forests, aspen plays a critical role in forest biodiversity and ecosystem function. Therefore, the persistence of this species...
Headwater streams represent the majority of the drainage area of a river network and provide many critical functions supporting aquatic and terrestrial ecosystem health. The riparian zones that surround these streams are transitional areas between terrestrial and stream ecosystems, which provide key habitat for aquatic and terrestrial organisms, especially during...
Fuel accumulation and climate shifts are predicted to increase the frequency of high-severity fires in ponderosa pine (Pinus ponderosa Dougl. ex Laws) forests of central Oregon. The combustion of fuels containing large downed wood can result in intense soil heating, alteration of soil properties, and mortality of microbes. Previous studies...