Our understanding of nitrogen (N) and phosphorus (P) variability in forested stream systems with minimal disturbance is confounded by the complex interactions of hydrologic and biogeochemical controls. In this thesis, our studies evaluate the variability of stream water N and P in a forested, headwater system in the Oregon Coast...
Forest harvest practices can impact nutrient concentrations and stream temperatures, altering aquatic ecosystems. To better inform future sustainable forest resource management practices, quantifying the impact of current practices on water quality, particularly in headwater streams is important. In this study, I quantified monthly nitrate-nitrite (N) and orthophosphate (P) concentrations, 7-day...
In recent decades, the occurrence of large, high severity wildfires has increased substantially in many parts of the world, including the western United States. These fires have the potential to impact water quality, aquatic ecosystems, and downstream communities for many decades. As such, it is increasingly important to understand the...
The extent and severity of wildfires in forested regions are increasing throughout many regions on the planet, including western North America. High-severity wildfires directly affect soils and vegetation by altering soil hydraulic properties, reducing soil organic matter, exporting carbon and nitrogen, and killing trees and understory vegetation. These impacts can...
Shallow subsurface flow and surface runoff are spatially and temporally variable in forested environments. The location and timing of this runoff depends on both site characteristics (e.g., vegetation, soil texture, geology, and topography) and on time-varying conditions (e.g., soil water content, precipitation type, duration, magnitude, and intensity). Forest management activities...
Timber harvesting practices can increase fine sediment inputs to streams due to increased hillslope soil erosion and mass wasting of roads, hillslopes, and stream channels. Excessive fine sediment depositions have been shown to impact aquatic ecosystems, fish habitat, and downstream community water supply. Despite these deleterious impacts, the influence of...
Wildfires can affect soil physical properties, resulting in changes in infiltration, hillslope runoff, groundwater recharge, and sediment and dissolved nutrients to streams. In November 2016, the Chimney Tops 2 Fire burned 4,617 ha of Appalachian hardwood forest in eastern Tennessee. A portion of the fire burned through a National Ecological...
The purpose of this study was to investigate the effects of wildfire on soil hydraulic properties of forested hillslopes. The study site was located within the Stouts Creek wildfire, which burned approximately 10,705 ha of forest in southwestern Oregon in summer 2015. Three soil hydraulic properties (soil moisture, unsaturated hydraulic...
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...
Mountainous headwater streams make up ~80 % of stream length globally and are strongly connected with catchment hillslopes and riparian areas, which can influence water quantity, quality, and availability for downstream uses. Accordingly, effective management of headwater streams and riparian zones to maintain desired ecosystem services downstream is critical, particularly...