I compared transpiration among different types of forest stands in the western Cascades of Oregon. The three major questions were: 1) How does transpiration compare between a young and old stand and why? 2) Does diversity of overstory trees affect transpiration? and 3) How is transpiration related to stream flow?...
Forest management is rapidly undergoing a transformation from a discipline based on efficient commodity production to one for multiple uses, especially on federally managed land in the United States. This new management paradigm has challenged silviculturists to develop and adapt forest management techniques that can deal with increased demands. Using...
Heartwood can have properties that are distinct from sapwood,
including resistance to insect and microbial attack. Despite the practical
importance of heartwood formation in trees, a review of the literature revealed
that little was known about the effects of environmental factors on heartwood
quality or how variations in heartwood properties...
Peroxiredoxins (Prxs) are dominant peroxide-reducing enzymes with two important roles: they protect all organisms from oxidative damage induced by peroxides, and in eukaryotes, they participate in hydrogen peroxide signaling pathways. This dissertation presents studies aimed at the biophysical characterization of select Prxs and a Prx reductase to elucidate their structure-function...
Quaking aspen (Populus tremuloides Michx) is a species with high phenotypic plasticity and a broad distribution that, in the last decade, has experienced climate stress-induced mortality called Sudden Aspen Decline (SAD). In order to help mitigate the effects of SAD in the future, we need a better understanding of aspen’s...
Understanding how the interactions and feedbacks between plant function, climate, and soils ultimately affects the terrestrial water balance and subsurface flow processes is major challenge in scientific hydrology. This dissertation summarizes the findings of a manipulative climate warming experiment, an observational field study that utilized stable-isotope tracers, and associated modeling...
Soils are the largest terrestrial pool of carbon, therefore it is critical to understand
what controls soil carbon efflux to the atmosphere in light of current climate uncertainty.
The primary efflux of carbon from soil is soil respiration which is typically categorized
into autotrophic and heterotrophic respiration. These two components...
This dissertation investigated the impacts of tree height upon a range of physiological and structural characteristics of Douglas-fir foliage; relationships between structural and functional trends with height; and compensatory mechanisms that mitigate height-related growth constraints. Height-related trends in foliar physiological and anatomical characteristics were examined both within trees as well...
Climate change impacts everyone’s food and water security. Increasing global temperatures accelerate the hydrologic cycle and consequently impact the water resources for billions of people worldwide. Countless models have been developed to represent various components of the hydrologic cycle at various spatial and temporal scales. These are often validated against...
Karl Jordan (1861-1959) was an extraordinarily productive entomologist who influenced the development of systematics, entomology, and naturalists' theoretical framework as well as their practice. He has been a figure in existing accounts of the naturalist tradition between 1890 and 1940 that have defended the relative contribution of naturalists to the...
