Forest Sciences Commons^™

Late Holocene Fire History Reconstruction Of Beaver Lake In The Northwest Lowlands Of The Olympic Peninsula, Grace Mckenney

All Master's Theses

Fire is an essential component of the landscapes and forests of the Pacific Northwest, including the temperate rainforests of the Olympic Peninsula. Previous fire history reconstructions from the peninsula show that fire return intervals varied throughout the postglacial period, primarily in response to climatic changes and corresponding shifts in vegetation. However, much less is known about the fire history of the low-elevation forests of the Olympic Peninsula and the role of cultural fire regimes in these environments. The purpose of this study was to reconstruct the paleoenvironmental history of a low-elevation study site, Beaver Lake, located in the northwestern part …

Influence Of Landscape Characteristics On Eastern Gray Treefrog (Hyla Versicolor) Occupancy Within Managed Forests Of Pennsylvania And Virginia, Susanna G. Sousa

Antioch University Dissertations & Theses

Understanding the characteristics that influence amphibian occupancy within forest ecosystems is necessary for effective conservation and management. My study focused on how eastern gray treefrog (Hyla versicolor) occupancy is influenced by environmental attributes quantified at various spatial extents. From May through July 2020 and 2021, we deployed autonomous recording units at 986 unique locations within managed forests in Pennsylvania and Virginia. Landcover class and road density were evaluated around each sampling location at ten spatial extents between 60 and 4000 m. Additionally, I measured aspect, elevation, soil drainage class, distance to nearest wetland, and basal area at each …

Quantifying The Ecological Effects Of Salix Fragilis On Riparian Habitat In Kittitas County, Washington, Landon Shaffer

All Master's Theses

Invasive species threaten plant community structure and function globally. Riparian areas, the zone near streams where water influences vegetation, are especially sensitive to invasive species colonization, suffering large-scale shifts in community composition. Salix fragilis (crack willow) is a nonnative riparian species abundant in the lower elevation tributaries of central Washington. Some speculate whether this willow should be listed as invasive in Washington, despite a lack of regional supporting evidence. I studied riparian communities dominated by either S. fragilis or native species in the Kittitas Valley and measured biodiversity, quantified differences in solar attenuation, and compared leaf decomposition rates to learn …

Effects Of Timber Harvest On Understory Vegetation Succession: A Time Series Study, Reese A. Poindexter, Trevor Weeks, Chad Bishop, Akasha Faist

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Timber harvest, as a necessary and common global practice, can significantly affect the ecosystems being harvested through opening the canopy, disturbing the understory, and resetting successional trajectories. This study examined how timber harvest influenced understory plant functional group dominance, understory species richness, and understory species dominance along a 40-year, or older, harvest timeline across two forest types (mesic and xeric) in Northwestern Montana, U.S.A. In our two forest types, vegetation sampling was completed at 208 sites with 1,040 quadrats across six timber-harvest timelines. Harvest timelines varied from the most recent at 1-5 years post-harvest to over 40 years as the …

Aboveground Biomass Density Estimation Using Deep Learning: Insight From Neon Ground-Truth Data And Simulated Gedi Waveform, Ashish Mahaur

Dissertations, Master's Theses and Master's Reports

Accurately estimating Aboveground Biomass Density (AGBD) is crucial for managing Earth's carbon cycle and informing climate strategies. NASA's GEDI mission advances global forest mapping, but traditional linear models often yield less reliable AGBD estimates. This study enhances AGBD estimation using deep learning models with NEON ground-truth data and simulated GEDI waveforms. We compared 1D CNNs, LSTMs, and pre-trained CNNs to traditional models. The ResNet152 model outperformed linear regression, achieving an R² of 0.68, demonstrating a 17% improvement. Our experiments also demonstrate the importance of large, diverse datasets, particularly for training deep learning models.

Assessing Understory Vegetation Response And Fuel Load Levels Following Silvicultural Treatments In Headwaters Forest Reserve, Humboldt County, California, Kyle James Railton, Madison Tatar

Undergraduate Scholarship

Old growth forests are important for ecological resilience, especially in temperate rainforest ecosystems. There are presently 3,000 acres of old growth forest within the 7,472 acres of the Headwaters Forest Reserve (HFR) in Humboldt County, California. Remaining acres were subjected to unsustainable logging practices, such as clearcutting, that resulted in a severely overstocked second-growth forest. The Bureau of Land Management (BLM) created a management plan for the reserve to restore previously harvested areas to their historic condition. The goal for the BLM is to accelerate growth rates of residual forests, to align them on a trajectory of achieving old-growth forest …

Development And Application Of Functional Immune Assays To Understand Disease In Wild Smallmouth Bass Populations, Cheyenne R. Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over recent decades, the scientific community has observed a disconcerting trend – a decline in the health and stability of smallmouth bass (Micropterus dolomieu) populations across the Chesapeake Bay watershed with growing economic and ecological implications. Disease, declines, and death have been observed in multiple locations, particularly in the Susquehanna and Potomac drainages with the adults disproportionately affected in the Potomac River basin and young-of-year in the Susquehanna River basin. There has not been a single or consistent cause to the declines or mortality events. More likely, it is believed immunosuppression relating to a complex mixture of stressors has been …

Stabilization Of Pfas-Contaminated Soil With Sewage Sludge- And Wood-Based Biochar Sorbents, Erlend Sørmo, Clara Benedikte Mader Lade, Julie Zhang, Alexandros G. Asimakopoulos, Geir Wold Åsli, Michel Hubert, Aleksandar I. Goranov, Hans Peter H. Arp, Gerard Cornelissen

Chemistry & Biochemistry Faculty Publications

Sustainable and effective remediation technologies for the treatment of soil contaminated with per- and polyfluoroalkyl substances (PFAS) are greatly needed. This study investigated the effects of waste-based biochars on the leaching of PFAS from a sandy soil with a low total organic carbon content (TOC) of 0.57 ± 0.04% impacted by PFAS from aqueous film forming foam (AFFF) dispersed at a former fire-fighting facility. Six different biochars (pyrolyzed at 700–900°C) were tested, made from clean wood chips (CWC), waste timber (WT), activated waste timber (aWT), two digested sewage sludges (DSS-1 and DSS-2) and de-watered raw sewage sludge (DWSS). Up-flow column …

Pcb Remediation In Transitional Floodplain Forests Along The Housatonic River, Soleil Laurin

Scripps Senior Theses

Human development affects natural environments in more ways than climate change, from the introduction of nonnative species and deforestation to pollution and urbanization. This is a case study examining the effects of PCB remediation on transitional floodplain forest along the Housatonic River in Western Massachusetts. The Housatonic River had previously been contaminated with PCBs and portions had been remediated. This study aims to determine the effects this remediation had on transitional floodplain forests, as well as provide a preliminary biodiversity assessment for sites that are planned to be remediated of PCBs by the Environmental Protection Agency. The study was carried …

Movement Behavior And Metapopulation Connectivity Of Stream Salamanders In Response To Disturbance Events, Kathryn M. Greene

Theses and Dissertations--Biology

Metapopulations are shaped by the dispersal between populations in a landscape. Disturbance events can disrupt this connectivity resulting in local population extinction. For my dissertation, I used a combination of empirical and theoretical techniques to examine dispersal in response to disturbance and assessed it’s population-level consequences. My research used capture-mark-recapture sampling techniques to evaluate stream salamander movement in response to (1) a supraseasonal drought and (2) mountaintop-removal-mining (MTR) and valley-filling (VF) and (3) agent-based simulation modeling to evaluate population extinction risk in response to varying dispersal and mortality rates.

First, I evaluated the effects of a supraseasonal drought, a severe …

Investigating Birds As Dispersal Vectors Of Litylenchus Crenatae Subsp. Mccannii (Anguinidae), The Nematode Associated With Beech Leaf Disease, Spencer Rock Parkinson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Beech leaf disease (BLD) is an emerging forest pathogen primarily affecting American beech (Fagus grandifolia, Ehrh.) in North America and has been attributed to tree mortality of sapling sized trees within five to seven years of infection. Symptoms typically occur in regenerating American beech thickets sprouting from roots of trees killed by beech bark disease. Scientists first observed BLD in Ohio in 2012 and currently has spread to 15 states in the USA and one Canadian province. The nematode Litylenchus crenatae subsp. mccannii (Lcm) is highly associated with BLD symptoms, interveinal chlorosis and defoliation of leaves, and is currently …

The Effects Of Experimental Warming On Root Respiration And The Fungal Community Of Tropical Forest Soil, Malik A. Sankofa

Dissertations, Master's Theses and Master's Reports

Climate induced changes in tropical forests fungal communities could impact diversity and abundance, forest health, and carbon release/sequestration. Under warmer soil temperatures and over time, we hypothesized that arbuscular mycorrhizal, pathogen, saprotroph diversity and abundance would increase, that ectomycorrhizal and overall fungal diversity and abundance would decrease, and that root respiration would be unaffected. Experimental warming (+2-3 ℃) was conducted on root ingrowth cores at the Tropical Responses to Altered Climate Experiment (TRACE) in Puerto Rico. ITS2 metabarcoding was used to analyze fungal diversity and abundance in control or warmed root/soil samples. We found that warming decreased arbuscular mycorrhizal diversity, …

Hydrologic Pathways Of A Northern Hardwood Catchment In The Great Lakes Basin Using End Member Mixing Analysis, Cory C. Burkwald

Dissertations, Master's Theses and Master's Reports

This study investigated the seasonality of hydrologic pathways, the role of wetlands in streamflow generation, and how hydrologic pathways affect the export of nutrients by streamflow in the Sturgeon River using endmember mixing analysis. The results indicated that streamflow consists of three main components: shallow subsurface water from wetland soils, shallow groundwater, and surface runoff from precipitation. Snowmelt plays a dominating role in regulating stream water chemistry (~80% volume at peak) during the snowmelt season and likely also after that. Wetland soils store snowmelt, together with rainwater though the fraction is unknown, and then gradually release through summer in the …

Validation And Improvement Of Forest Health Risk Maps: A Case Study With Maple Decline/Dieback, Joseph R. Beeson

Dissertations, Master's Theses and Master's Reports

Forest health data collected in a two-phased survey of maple dieback was used to build on previous work, extending analysis into mapping implications. Using the National Insect and Disease Risk Maps (NIDRM) published by the US Forest Service as a baseline, we compared our collected data from 2009-2012 and 2021-2022 with the published 240m resolution sugar maple decline risk map, finding the NIDRM map to be a poor predictor of sugar maple dieback measured at the plots. Measured sugar maple crown dieback was also compared to measured soil characteristics and nutrient levels, and augmented with soil survey maps and long-term …

The Role Of Neighborhood Effects In Maintaining The Hardwood-Hemlock Mosaic, Adam Z. Milenkowic

Dissertations, Master's Theses and Master's Reports

Neighborhood effects are processes mediated by canopy trees that influence the ability of a species to replace itself following canopy mortality. Sugar maple (Acer saccharum Marsh.) and eastern hemlock (Tsuga canadensis (L.) Carr.) are the dominant trees in old-growth northern hardwood forests of Upper Michigan and have been observed to form monodominant patches in the region. Few studies have independently evaluated the demographic and ecological mechanisms that lead to the compositional stability of hemlock and sugar maple patch development. Tree demography data from eight long-term 0.5 ha old-growth plots in Upper Michigan indicate neighborhood effects are playing a …

Bioenergy Cropping Systems Established On Marginal Lands: Effects Of Land Use, Energy Crop, And Fertility Amendments On Soil Health, Mica M. Keck

Graduate Theses, Dissertations, and Problem Reports (ETD)

Bioenergy crops offer a promising strategy for renewable energy production, accompanied by carbon (C) storage benefits when managed sustainably. Utilizing marginal lands for energy feedstock production presents an opportunity for bioenergy generation and concurrent climate mitigation without competing with food crops. However, achieving optimal yields requires strategies to restore soil fertility, which require increased understanding of the interactive effects of prior land use, energy crop species, and fertility amendments available. This study, conducted as part of the Mid-Atlantic Sustainable Biomass (MASBio) Consortium, investigated the effects of biochar incorporation—a C-rich charcoal derived from biomass, intended for soil enhancement—on bioenergy cropping systems …

Characterizing Prescribed Fire With Terrestrial Lidar In The New Jersey Pine Barrens, Samuel Rhule Stockton

Graduate Theses, Dissertations, and Problem Reports (ETD)

Prescribed burning has become a commonly used tool in the mitigation of wildfire, though monitoring the way it changes ecosystems has historically been a time-intensive process. Rapid change across ecosystems has necessitated advancements in remote sensing technologies to quantify the changes taking place. Single-scan terrestrial LiDAR scanning is one such method of monitoring these changes through the quantification of ecosystem structural characteristics. Acute disturbance events such as fire can transform the structure of an ecosystem, and by extension, change the way that ecosystem functions. The purpose of this study is to analyze the changes in vegetation density and distribution following …

Wildfires Are Burning Less Frequently And More Severely Than Historically In The Western Us: A Novel Approach To Calculating Fire-Regime Departures, Jeffrey Ryan Chandler

Graduate Student Theses, Dissertations, & Professional Papers

Changing climate, vegetation, and fire exclusion are altering and homogenizing fire-regime attributes compared to historic conditions. Fire-regime changes are commonly quantified using departure metrics, which are often based on measures of central tendency (i.e. changes in the mean). These metrics can mischaracterize complex changes to the distributional characteristics of fire-regime attributes. Here we develop a fire-regime departure metric that quantifies nonparametric distributional changes to fire-regime attributes over time. We use this metric to compare fire frequency and severity between historical (~1600-1880) and contemporary (1880- 2021) time periods in western US forests. Our analysis revealed that 89% of Western US forests …

Integrating Western Science And Indigenous Knowledge For Just Practices In Conservation, Cierra Lea Keith

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.