Soils contain the largest pool of carbon that is actively cycling on human timescales, leading many to view soils as a natural climate solution with multiple co-benefits. The field of soil science is rapidly evolving, but without a unified understanding of soil carbon dynamics. This dissertation leverages two distinct long-term...
Pacific Northwest temperate rainforests are anticipated to experience increasingly frequent and severe wildfires in the foreseeable future due to climate change, increased fuel loads, and deforestation. Soil, underlying these forests, is the largest terrestrial carbon (“C”) reservoir. Fire disturbance influences soil C persistence, the timeframe and magnitude of which remain...
Soil contains approximately 75% of the carbon pool on land - three times more than the amount stored in living plants and animals (Schlesinger 1999). Therefore, soils play a major role in maintaining a balanced global carbon cycle. Models of the soil carbon ecosystem assume a strong relationship between organic...
Sea-salt aerosols (SSA) impact the cycling of nutrients within coastal soils, including the mobility of dissolved organic carbon (DOC) and ammonium, denitrification, and litter decomposition. These aerosols are formed during tumultuous weather in the open ocean and are transported and deposited inland by wind. Soils closer to the ocean are...
Urban agriculture (UA) is defined as the production of food crops or livestock within urban areas. Despite its popularity in the United States, research into UA systems suffers from a general underrepresentation of commercial urban systems. As a result, urban growers often have unique technological needs that are unmet by...
Soil is a complex living system with high heterogeneity, which makes locating soil map boundaries a challenge. In traditional soil survey, the placement of soil map boundaries relies largely (at least initially) on identifying the soil-forming factors of biota and topographic relief through stereo aerial photo pairs. Future soil survey...
Forest soils contain a substantial portion of global terrestrial carbon stores. Forest management can influence the soil carbon pool and how soil organic matter functions. The long-term productivity of forests is an ongoing goal where land managers utilize biomass and timber. A site-specific understanding of intensively managed forests can ensure...
Many wood composites are known to poorly resist the effects of moisture and temperature extremes over time. Degradation of adhesive bonds, irreversible thickness swell and dimensional instability result in a decrease of properties and a possible failure of the material. Accelerated weathering has become an essential tool for assessment of...
Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM compositions in catchments of the western U.S. are poorly understood. UV and fluorescent spectroscopy is a simpler, faster, and less...
Soil food webs process the majority of terrestrial carbon, and influence overall ecosystem function. A primary distinction among soil food webs is based on fungal versus bacterial pathways of decomposition; these lead to fundamentally different soil function, and are expected to differ in dominance between meadows and forests. This assumption...
There is no doubt that adhesive penetration plays an important role in wood bondline joint performance and durability; yet, to date there is no direct experimental evidence linking penetration depth with bond performance. This is, in part, because adhesive penetration is commonly assessed with various 2D microscopy techniques that are...
Forests are one of the largest repositories of terrestrial C. Understanding factors that drive organic matter transformations and nutrient efflux from these systems is therefore highly important. Temperate forests are of particular significance due to the large fraction of C that is stored below ground in the soil. Characterizing nutrient...
In the last decade regulatory bodies have begun to implement standards to protect populations of non-human biota (NHB) from the consequences of radiation exposure. This is a departure from previous regulatory frameworks which were concerned only with protecting man. The implementation of these new standards has started an ongoing discussion...
Lower and Middle Devonian strata crop out on the former
stable carbonate platform that existed in the Quinn Canyon Range,
through the carbonate shelf edge in the Pancake Range, to the
carbonate slope and outer-shelf basin in the Reveille Range.
The strata of the Reveille Range record a transition from...
Many studies suggest that weedy plant species are most successful when
soil nitrogen in abundant. Consequently, I used soil nitrogen manipulations to
determine if altering nitrogen would affect the establishment of both weedy and
native plant species in a western Oregon wetland prairie. In two studies, we
added carbon amendments...
During the past several decades, earthquakes have caused extensive damage to
buildings, including wood-frame, single-family dwellings, in the United States. In
order to mitigate future losses, existing buildings in earthquake prone areas should be
evaluated for their seismic safety. This is also an important issue for buildings in
Oregon due...
Forest harvest can have significant impacts on forest ecosystems that may influence the capacity of soils to sequester carbon (C). The microbial community controls decomposition, which is a critical process in partitioning litter- and root-C between CO₂ and storage in semi-permanent soil-C pools. The objectives of this study were to...
Most carbon (C) transformations in soil are carried out by a diverse and complex soil microbial community. The size and composition of the soil microbial community is determined by poorly understood interactions between the quantity and chemical composition of plant inputs, as well as climate. Given the metabolic diversity of...
Streamflow patterns are a result of the interaction of many factors, including climate, vegetation, geology, and topography. Analyses indicate that streamflow patterns have changed around the United States over the past century, raising questions about the possible role of climate variability as a driver of water yield. This thesis examines...
Changes in the type and amount of plant inputs can occur gradually, as with succession, or rapidly, as with harvesting or wildfire. With global change it is anticipated that both gradual and immediate scenarios will occur at increasing frequency. Changes in vegetation inputs alter the quality and quantity of soil...
Successful conservation management requires an understanding of how species respond to intervention. Native and exotic species may respond differently to management interventions due to differences arising directly from their native or exotic origin (i.e., provenance) or from differences in life-history or phylogenetic lineage that are associated with provenance. Thus, selection...
Seasonal and annual patterns of N fluxes and concentrations in streamwater in six conifer-dominated watersheds at the H.J. Andrews Experimental Forest, OR, were studied to gain insight into the factors that influence N retention in this ecosystem. Processes affecting N flux in streamwater differed between organic (DON) and inorganic (DIN;...
Most soil organic C is in a stable form, associated with clay minerals in the upper soil profile. Upon environmental and land-use changes, stable soil C is subject to losses, which influence the global C cycle and the productivity of terrestrial ecosystems. However, mechanisms controlling soil C destabilization are not...
By emulating natural disturbances such as wildfire, managers hope to maintain biodiversity in managed forests. Leaving residual (live) trees in harvested areas is key to this strategy. However, the effectiveness of this approach is unknown. I surveyed songbirds in 176 stands in the Rocky Mountains of southeastern British Columbia, Canada,...
This thesis is comprised of two manuscripts that relate to forest-based management strategies in the context of market-based climate change mitigation policies. The work questions the appropriateness of a singular focus on carbon sequestration given the albedo effect and its possible countervailing climatic impacts. Through a review of salient literature...
This study explored scientists' epistemological views of science and compared
views based upon scientists' discipline area and primary investigative approach.
Participants were 24 scientists, averaging 25 years research experience, representing four discipline areas: life science (10), Earth and space science (5), physics (5), chemistry (5); and four investigative approaches: experimental...
Streamside buffer strips provide numerous benefits to stream ecosystems. The buffer strips create shade, provide shelter for wildlife, act as barriers to logging debris during and after timber harvest, and serve as a continued source of large woody debris. Quantifying woody inputs resulting from windthrow provides managers with estimates for...
The study examines the effect of forest clearance on fire occurrences in major islands of Indonesia, namely: Borneo, Sumatra, Sulawesi and Irian Jaya. The working hypothesis of the study is that forest clearing is a necessary predecessor for extensive fires to occur. The study is designed to test the idea...
The specific objectives of this dissertation are to determine subsurface flow
behaviors across different antecedent wetness conditions from a top-down perspective
and to mechanistically assess the hydrological controls on DOC and N transport at the
hillslope and catchment scale. The study area is a small catchment where hillslopes
issue directly...
Due to growing global competition, especially in the last decade, the United States wood and wood-based industries have suffered significant market share losses. The wood industry in Germany is facing similar challenges. To stay competitive in an increasingly global marketplace, many wood manufacturers are adopting new management/manufacturing approaches. Lean manufacturing...