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...
Sediment cores were retrieved from a landslide-dammed lake, recording events back to the 5th century AD in a forested, mountainous catchment. These cores provide an opportunity to compare the impacts of known recent perturbations, including floods and timber harvesting with those of the early period of the core, flood, fire,...
Forest soils of the Pacific Northwest contain immense amounts of carbon (C). Increasing acreage burned by severe wildfire in the western Oregon Cascades threatens belowground carbon stocks and future site viability. This study investigates forest soil carbon changes after the 2020 Holiday Farm wildfire in a young, intensively managed Douglas-fir...
Climate change is occurring at an increasingly rapid rate, with impacts heightened in the cold regions of the world including the Arctic. Warming effects are widespread, with one impacted process – freeze-thaw cycles – increasing in frequency and potentially triggering additional changes in permafrost soils that have previously acted as...
Public lands in the Pacific Northwest are managed for multiple uses including timber production, recreation and aesthetic value, maintaining wildlife habitat, conserving native species, and carbon storage. Wildfires impact large areas encompassing broad environmental conditions. Interactions among underlying environmental gradients and alteration of overstory competition by fire of varying severities...
Landscape positions have been used to determine soil properties. My soil study in Monteverde on the Pacific slope of Costa Rica was designed to examine soil-landscape relationships for sites with various land use histories and management. Soil pits were dug at Nacimiento y Vida, Crandell, Curi-cancha, La Calandria, and Finca...
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...
In ponderosa pine (Pinus ponderosa) forests of the western United States, prescribed fires are used to reduce fuel loads and restore historical fire regimes. The season in which prescribed burns are performed and the interval between burns can have complex consequences for the ecosystem, including soil carbon cycling through the...
In intensively managed forest plantations in the northern Oregon Coast Range, herbicides are often applied during site preparation and early stand regeneration to reduce competition for resources for planted conifer seedlings. In addition to reducing competition for crop trees, herbicide applications may affect soil processes including decomposition and nutrient cycling,...
Arctic warming is exposing thawing permafrost to repeated freeze-thaw, a disruptive process that can alter soil biogeochemistry and physical structure. To investigate the impact of permafrost exposure to freeze-thaw, soil response was tested across three scales: 2.5 cm³ aggregates, a forested hillslope, and two sites at contrasting latitudes. XCT imaging...