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...
I studied developmental rates in a suite of temperate and tropical passerine bird species from the New World to test the hypothesis that tropical passerines exhibit slower patterns of growth and development than temperate birds. I also investigated how the expression of several developmental rates varied with life history traits...
A number of researchers view farmers’ markets as an appropriate vehicle for
re-embedding food markets into communities (O’Hara & Stagl, 2001, Feenstra, 2002,
Lyson, 2005). Amidst astounding growth in the number of farmers’ markets in the
United States in recent decades, many markets struggle and fail. Recent research
suggests that...
Belowground carbon (C) storage and quality of soil organic matter (SOM) in
forest soils have implications for sustainable forest management and C sequestration,
but how these pools change in response to management is poorly understood. I
investigated whether fertilization and competing vegetation control, applied alone or
in combination early in...
Two case studies of 5 ecosystems were used to examine the nitrogen fixation rate of red alder (Alnus rubra Bong.), varnishleaf (Ceanothus velutinus var. laevigatus (Hook.) T. & G.), deerbrush (C. i ntegerrimus H. & A.), and snowbrush (C. velutinus var. velutinus Dougl. Ex Hook). The first case study assayed...
Predictive Soil Mapping (PSM) has recently become an attractive method for soil scientists wishing to develop a more objective and efficient approach to mapping soils. Due to the potential PSM has for reducing the effort to produce soil maps, as well as its ability to improve the classification accuracy of...
Thermo-hygro-rheology of wood-adhesive systems plays an important role during the hot pressing process of wood based composites. The principal objective of this research is to quantitatively study the thermo-hygro rheological characteristics of wood-adhesive systems used in such composites. This is with a view to providing material characteristics which may be...
Previous studies of bird communities in the mid-Willamette Valley, Oregon, indicated that Oregon white oak (Ouercus garryana) stands supported more cavity-using bird
species than sympatric stands of Douglas-fir (Pseudotsuga menziesii). Mature Oregon oak stands are being harvested and few are regenerating. I compared cavity availability for hole-using fauna among 10...
This research focused on anaerobic transformation of trichloroethene (TCE), a
groundwater contaminant. The mixed anaerobic Evanite culture (EV) was studied to determine community behavior and composition responses to different electron donors and chloroethene electron acceptors. The potential toxicity from high concentrations of TCE and its daughter product cis-1,2-dichloroethene (cDCE) was...
Studies of avian movement ecology afford essential insights regarding species' life histories, population dynamics, habitat and resource requirements, and other ecological relationships. While it is widely recognized that events in different stages of the annual cycle have important implications for processes in avian ecology, evolution, and conservation, challenges associated with...