Canopy gap formation is a major factor contributing to maintenance of overstory species diversity and stand structure in forests and may be integral to development of understory shrub and herb layers as well. Acknowledgement of gap formation as a fundamental feature of natural forests has led to consideration of gaps...
Previous observations of light levels and phytoplankton abundances along the Oregon coast demonstrated that phytoplankton attenuated light sufficiently to potentially limit the growth of intertidal macrophytes and therefore structure local intertidal communities. Inspired by this observation, in spring 2004, I initiated a study to quantify the direct and indirect benthic...
Four studies were conducted on late-summer diet quality and quantity of cattle (Bos taurus), mule deer (Odocoileus hemionus hemionus), and elk (Cervus elaphus) in response to prior grazing by cattle and elk on mixed-conifer rangelands and on related research techniques. In our first study we assessed a photographic technique to...
Although the Pacific Northwest has the least proportion of non-native plant species in relation to other regions of North America, exotic species continue to spread into mountainous areas, including the Cascade Range. In a forested landscape, road networks can act as corridors for exotic plant dispersal and establishment, helping species...
This document provides information on the palatability of plants on Mongolian rangelands including native and introduced vascular plants by major seasonal periods: winter (January - March), spring (April- June), summer (July - September), and autumn (October - December). In addition to this, some species of valuable lichen species are also...
Tree species directly and indirectly affect soil nutrient cycles. I sought to characterize soils and foliage associated with four common canopy tree species (Douglas-fir, western hemlock, western redcedar, and bigleaf maple) in mixed-species old-growth forests of the Oregon Coast Range and to determine whether and how soils differ among the...
We evaluated the regeneration behavior and early growth rates of 10 non-pioneer canopy tree species in medium-height, semi-evergreen dry tropical forest in Quintana Roo, Mexico. These species provide timber and non-timber forest products for local communities and include evergreen and deciduous species with varied dispersal mechanisms. The species were Coccoloba...
Juniper is a native species to Oregon and confers ecological benefits to wildlife when it is at savannah and transitional densities. Its range and extent have fluctuated with climatic change, but the current range expansion is unprecedented in its extent. The range expansion has been associated with the degradation of...