Forest Biology Commons^™

Silviculture For Coastal Forest Resilience: Promoting Forest Regeneration And Managing Invasive Plant Species, Ryan Bohannon

All Dissertations

Coastal forests of the southern United States and the ecosystem services they provide are threatened by an intensifying and interacting suite of disturbances associated with global change. Silvicultural strategies such as enrichment planting, invasive plant management, and browse mitigation treatments can enhance the resilience and adaptive capacity of forests to these threats by promoting sustainable regeneration and recruitment dynamics. To improve our understanding of coastal forest disturbance regimes and their impacts on forest stand dynamics, I conducted a systematic literature review of maritime forest disturbance ecology and identified coastal storms, ungulate browsing pressure, and invasive plants as primary disturbances shaping …

Exploring The Effects Of Pest-Induced Hemlock Mortality On Growth In Neighboring Trees, Sidney L. Booher

McNair Culminating Research Projects

Trees provide many important products and services to humans. In particular, tree growth is critical to carbon storage, air and water quality, and helps determine demographic processes like population growth and reproductive success. Importantly, tree growth is sensitive to both abiotic (environmental) and biotic factors and is vulnerable to ecological disturbances. Understanding how tree populations respond to disturbances, like invasive pests, is therefore crucial to formulating timely and effective forest management practices.

Here, I used tree ring analysis to investigate how competition for water between neighboring trees changes following the decline of Eastern and Carolina Hemlock(ECH) trees due to the …

Clethra Alnifolia: A Fact Sheet For Seed Transfer Considerations, Taylor Houggy

Plant Science Articles

Clethra alnifolia is a highly prized fragrant deciduous shrub, often found in many home gardens across Eastern North America. Despite its popularity in the landscape industry, there is little research comparing C. alnifolia's natural habits in the wild to its habits as a landscaped cultivar. Information such as flowering phenology, genetic diversity, and growth habits have the potential to change considerably depending on C. alnifolia's location. Because of this, it is important that landscape growers as well as forest conservationists have access to ecological fact sheets in order to make informed decisions when transferring seed to different areas. In this …

Forest Overstory Mortality & Recruitment Patterns Eight Years Following Wildfire In The Southern Appalachians, Ruth Cumberland

All Theses

In this study, we investigated patterns of forest overstory mortality and recruitment eight years after wildfire in a large wildfire site the Southern Appalachians, a topic that has not been thoroughly investigated to date. With evidence that pre-fire drought promotes post-fire mortality through impaired physiological function and increased fuel consumption, unknown patterns following wildfire are important to study under shifting climate and land-use conditions. In Chapter 1, three areas of interest were investigated: (a) functional group mortality response to wildfire effects, (b) temporal differences in early (1-3 years) and late (5-8 years) periods of delayed forest overstory mortality patterns following …

Testing The Intermediate Disturbance Hypothesis On Anthropogenic Pressure In Central Alabama, Gavin Terrell

Theses

Biodiversity is fundamental to maintaining ecosystem structure and function globally. Prior to the late 20th century, ecological theory generally predicted that biodiversity would be highest in systems experiencing minimal disturbance. However, Joseph H. Connell challenged this view with the Intermediate Disturbance Hypothesis (IDH), which posits that species diversity peaks at intermediate levels of disturbance and declines under conditions of both low and high disturbance. Although widely cited, the applicability of the IDH to natural systems remains debated, particularly in the context of anthropogenic disturbances and when diversity is measured beyond species richness alone.

This study evaluated the predictions of the …

Leaf Droppage Delayed In Sugar Maple Trees On An Urban To Rural Gradient, Isabella S. Bastien, Isabella Bastien

The Cardinal Edge

This study investigates the timing of leaf abscission in Sugar Maple (Acer saccharum) trees along an urban-to-rural gradient in Louisville, Kentucky, to determine how proximity to urban environments influences leaf drop. We hypothesized that urban trees would retain their leaves longer than suburban or rural trees due to environmental stressors and tested this using weekly leaf collection and canopy cover measurements from three locations—urban, suburban, and rural. Results showed that urban trees exhibited delayed leaf drop and slower canopy opening compared to suburban and rural trees. These findings suggest that urban stressors significantly alter tree phenology, which may signal underlying …

Impacts Of Native And Nonnative Plant Species On Avian Community Diversity, Matty John Mackay, Steven Van Dang, Brandon Lee Corn

SPARK Symposium Presentations

Avian communities play an essential role in maintaining a healthy ecosystem dynamic by regulating insect populations, assisting in plant pollination, and seed dispersal. These contribute to the overall health of natural ecosystems and mitigate ecological disruptions that would arise in their absence. However, the introduction of non-native invasive plant species can interrupt the balance avian communities bring to ecosystems by reducing availability of food sources, altering habitat structures, increasing competition among individuals, and disrupting ecological relationships through rapid invasion of ecological spaces. Point count observations of birds at Shelby Bottoms Park, Nashville, Tennessee in areas dominated by non-native privet and …

Assessing Forest Health And Small Mammals After A Limited Suppression Wildfire In Colville National Forest, Samantha J. Kennel

EWU Masters Thesis Collection

In the face of a wildfire crisis, there is a growing need to expand the pace and scale of forest treatments, including the strategic use of wildfire as a management tool. However, ecological outcomes remain uncertain in forests shaped by more than a century of fire suppression. The 2022 Thor Fire, a managed wildfire in the Colville National Forest, Washington, provides an opportunity to evaluate forest health in a relatively understudied system. Using a control–impact design, I established 100 monitoring plots in burned and adjacent unburned forests to assess how wildfire and fire severity influence forest structure, fuels, and tree …

Ectomycorrhizal Fungi Associated With Pinus Species Of California's Northwestern Coast, Monika Audrey Richardson

Cal Poly Humboldt theses and projects

Ectomycorrhizal (ECM) fungi are vital for increasing host plant uptake of nutrients and stress tolerance within ECM forest ecosystems. The species assemblage of ECM fungi can vary locally in response to numerous biotic and abiotic environmental factors. In California’s northwestern coast the occurrence of three Pinus species, along with a disjunction between populations of Pinus muricata in Mendocino and Humboldt Counties, offer a unique opportunity to investigate the spatial and host effects on pine-associated ECM fungi. Ectomycorrhizal fungal community structure was quantified from host tree roots and sequenced sporocarps occurring at the same sites to create a project specific ITS …

Some New Ecological Aspects Of The Lesser Sunda Endemic Drepanosticta Berlandi (Odonata: Zygoptera: Platystictidae), Muhammad Zulhariadi, Muhammad Setyo Nugroho, Nurul Hidayani

Makara Journal of Science

Drepanosticta berlandi is an endemic damselfly in the Lesser Sunda region of Indonesia, which was first recorded on Lombok Island in the 19th century. Albeit recognized for a century, information on its ecology is still lacking; hence, this study aims to reveal its distribution and habitat preferences. The research was conducted at the Tibu Ijo Waterfall tourist area in West Lombok Regency using line transects combined with field survey in the Kekait River and on footpaths on both sides of the river. Vegetation density, topography, and land survey temperature (LST) were measured at the sampling area using ArcGIS 10.4.1 software. …

The Ecology Of Arthropod Rain In A Tropical Forest., Andrew Robert Seiler

Electronic Theses and Dissertations

Tropical forests are structured by complex vertical linkages and nutrient exchanges between canopy and understory habitats. These linkages include the downward flux of organisms, the movement of canopy fauna, and the recycling of nutrients through litter and organic matter deposition. This dissertation investigates arthropod rain and its role in connecting the canopy and forest floor processes in a lowland tropical forest in Panama. Chapter 2 quantifies “arthropod rain”, the fall of canopy arthropods into the understory. Using pan and pole traps, I measured the composition, abundance, and biomass of arthropods falling from the canopy and assessed environmental drivers of the …

Examining Private Landowner And Stakeholder Attitudes, Perceptions, And Knowledge Of Prescribed Fire In Louisiana, Chloe E. Crawford

LSU Master's Theses

Periodic fire was a primary driver of ecosystems across the Southeastern United States for millennia; however, fire suppression policies have become pervasive in the United States and led to increased fuel loads in forests as well as reduced biodiversity and reduced disease resilience. Prescribed fire presents a risk mitigation strategy and land management tool whereby practitioners can apply fire to the landscape in a controlled manner, thus reaping the benefits of fire while minimizing the risks associated with fire. Land in Louisiana is primarily privately managed and owned, so state-level conservation goals cannot be met without private landowner participation. As …

Catching A Fever: A Comparison Of Vachellia Xanthophloea Populations In The Limpopo And Luvuvhu River Floodplains Of The Makuleke Contractual Park, Kianie B. David

School of Natural Resources: Dissertations, Theses, and Student Research

This study investigates patterns of stand structure regeneration, growth characteristics, and coarse woody debris (CWD) patterns in Vachellia xanthophloea (fever tree) stands within the Makuleke Contractual Park (MCP), a semi-arid savanna system in northern Kruger National Park (KNP), South Africa. Fieldwork was conducted across two stand types: a monospecific fever tree stand in Rietbok Vlei and a mixed-species stand in the Western Nhlangaluwe Floodplain where fever tree is established with Faidherbia albida (ana tree). Data were collected from 20 total 1/4-acre (1,011 m²) circular plots between both stands in 2024 and 2025, including seedling root collar diameter (RCD), …

Belowground Biomass Shifts Along A Temperate Forest Edge, Lara Holbrook Roelofs

Dartmouth College Undergraduate Theses

Anthropogenic land use change and development has caused widespread global forest fragmentation, resulting in a greater proportion of forests at or near a forest edge. Temperate forests are the most fragmented forest biome, and forests in the Northeastern U.S. are particularly fragmented due to a history of intense land use and development pressure. Nearly a quarter of these forests are now within 30 meters of a forest edge. These edge ecosystems have distinct abiotic and biotic gradients that differentiate them from forest interiors, including increased light, temperature, and exposure to wind and other disturbances, as well as decreases in humidity …

Monitoring Mangrove Dynamics And Evaluating Future Afforestation Potential In The Egyptian Red Sea, Rasha M. Abou Samra, Mansour Almazroui, Wenzhao Li, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Mangrove forests are vital for ecosystem services and coastal management but face stressors from anthropogenic activities and climate change. This study estimates the extent and afforestation potential of mangroves along the Egyptian Red Sea coast from 1984 to 2022 using NDVI derived from Landsat-5 and Sentinel-2 data in Google Earth Engine. Aboveground biomass (AGB), belowground biomass (BGB), carbon (C) stock, and CO₂ sequestration potential were evaluated using Sentinel-2 and elevation data. Future afforestation suitability (2020–2050) under SSP2-4.5 and SSP5-8.5 scenarios was assessed with the MaxEnt model. Mangrove area increased from 0.95 km² in 1984 to 1.46 km^{2 …}

Patterns Of Fire History And Vegetation Changes In The Last 5000 Years: A Paleoecological Study Of Iquitos, Annabel Zwarts

Theses and Dissertations

The vegetation of the Amazonian rainforest is hypothesized to have been shaped by pre-Columbian activities, such as burning and palm management to various extents. Management of palms is hypothesized to have caused some of the most useful species to become hyperdominant in Amazonia. This study investigated the extent to which human activities over the past 5000 years affected palm abundances in mature lowland rainforests near Iquitos, Peru. I used phytoliths and charcoal from soil cores to determine the history of local floras, and modern palm surveys to compare modern phytolith occurrence with modern vegetation. Because pre-Columbian activity clustered along the …

Life After Death: Investigating The Resistance And Recovery Of Fungal Communities To Foundation Tree Mortality, Jessie F. Marlenee

Biology ETDs

Tree mortality can have cascading effects on the composition and resilience of interacting fungal communities. Yet, little is known about the impact tree mortality, distinct from abiotic drivers (i.e., drought), has on these communities. This dissertation focuses on the resilience of fungal communities to experimental tree mortality in a piñon-juniper woodland. In chapter one, I found that piñon mortality reduced piñon fine root biomass and piñon mycorrhizal fungal diversity, whereas juniper mycorrhizal fungi were unaffected by juniper mortality. In chapter two, I revealed that piñon mortality altered the composition and spatial structure of mycorrhizal and saprotrophic fungi in the soil, …

Occurrence Of Spotted Wing Drosophila (Drosophila Suzukii) In Wild Berries In Forested Areas Of Marquette And Keweenaw Counties, Upper Peninsula Of Michigan, Alexis M. Shatrau, Erika I. Hersch-Green

The Great Lakes Entomologist

Spotted-wing Drosophila (SWD, Drosophila suzukii Matsumura, Diptera: Drosophilidae) is an invasive fly that targets unripe soft-fruits causing premature ripening, dehiscence, and rotting. While the presence of SWD in agricultural systems is well-documented, much less is known about the host range of SWD in wild areas, especially in more northern latitudes where colder temperatures and short summers are thought to restrict their life-cycles and limit population growth. In 2019 and 2020, we collected wild berries from two counties in the Upper Peninsula of Michigan, with long, cold winters, to determine the prevalence, host range, and seasonal/temporal variation of SWD. We found …

Woody Plant Reinvasion Shortens The Lifespan Of Grassland Restoration Treatments, Dillon T. Fogarty, Michele Beadle, Craig R. Allen, Christine Bielski, Dirac Twidwell

Biology Student Work

An important question in restoration ecology is whether restored ecological regimes are more vulnerable to transitions back to a degraded state. In woody-invaded grasslands, high-intensity fire can collapse woody plant communities and induce a shift back to a grass-dominated regime. Yet, legacies from woody-dominated regimes often persist and it remains unclear whether restored regimes are at heightened vulnerability to reinvasion. In this study, we utilize a 17-year history of fire-based restoration in Nebraska's Loess Canyons Experimental Landscape to determine whether restored grassland regimes experience faster rates of Juniperus virginiana (eastern redcedar) reinvasion compared to the initial invasion process in adjacent …

Dam It All: A Multi-Scalar Investigation Into The Ecological Role And Function Of Beaver Dams, Kenneth Larsen

Dissertations, Master's Theses and Master's Reports

The central theme of this dissertation is ecological scaling, which examines how small, localized features, such as beaver ponds, contribute to large-scale watershed processes and how different modeling approaches at various scales reveal distinct insights. Through a combination of probabilistic modeling and high-resolution empirical research, this work demonstrates that small ponded systems, particularly those created by beavers (Castor canadensis), serve as critical biogeochemical control points, whose contributions to sediment and nutrient dynamics have been historically underestimated.

In Chapter 1, I contextualize this research within the broader fields of freshwater ecology, watershed modeling, and ecological restoration. I introduce the …

Age Class Is Not Related To Size Or Composition Of Home Ranges Among Suburban White-Tailed Deer During Parturition, Nathan D. Pyburn

Journal of Earth and Life Science

How white-tailed deer use the landscape in an urban environment can help us understand the effects of urbanization on deer populations. White-tailed deer form observable matriarchal hierarchies in studied populations. This study examines the matriarchal structure, home range size, and home range composition of 25 collared white-tailed deer within the city limits of Bemidji, MN. The results found no significant difference between age class and home range size or composition. However, movement metrics from yearling and mature age classes were more similar than the juvenile age class females. I propose this is because social acceptance between mature females was higher …

Sugar Maple (Acer Saccharum Marsh.) Tree-Ring Growth And Carbon Stable Isotope Responses To Nitrogen And Climate, Libbie Ring

Dissertations, Master's Theses and Master's Reports

This dendrochronological and stable carbon isotope study used tree rings from sugar maple (Acer Saccharum Marsh.) collected at long-term nitrogen (N) amended sites throughout Michigan to understand N amendment and deposition, climate, and growth relationships. Climate responses varied by site, however, we found importance in grouping sites by “productivity” which is related to inherent N and soil nutrients. Our results did not detect an overall effect of N amendments on growth during the treatment period. However, data shows N amendments benefiting larger diameter trees, while smaller diameter trees responded more positively without amendments, especially on more productive sites. Results …

Acer Rubrum: Descending Towards Forest Dominance, Elyssa L. Pearson, Christopher M. Gough

UROP Posters

Acer rubrum, more commonly known as the red maple, is a hardwood, late successional species of tree commonly planted for its deciduous nature and vibrant coloring of its leaves in the beginning of autumn (Abrams, 1998). The species is very tolerant of varying light and soil moisture levels and often dominates sub and mid-canopy levels of hardwood forests (Missouri Botanical Gardens). It was hypothesized that as the I moved from an upland location to a lowland location near a wetland that the A. rubrum trees would be more productive and have a greater above ground biomass. This was not …

The Role Of Floodplain Complexity In Wood Turtle Habitat Use, Laura S. Deming

Antioch University Dissertations & Theses

Wood turtles occupy cold, low-gradient riverine habitat throughout the northeastern United State and southeastern Canada. Stream alterations, such as dams, channel straightening, and floodplain development have diminished the natural hydrologic and sedimentation regimes that result in complex channel and floodplain geomorphology. Studies throughout the species’ range have quantified many aspects of their habitat, but none have quantified components of geomorphology of wood turtle sites. The goal of this study was to explore the role of stream channel and floodplain geomorphology in wood turtle habitat use, with specific objectives to (1) quantify components of stream channel and floodplain geomorphic complexity, (2) …

Economic Analysis And Profitability Of Honey Production And Marketing In Cross River State, Nigeria, Joseph A. Ugbe, Tee T.N., Ancha P.U

Journal of Bioresource Management

The significance of honey in the socio-economic livelihoods of rural and semi-urban populations is paramount, as it tackles issues such as unemployment, income, and ecosystem preservation. The decrease in the timber industry has caused numerous individuals who rely on forests for their income to be without jobs, making it difficult to find other ways to make a living. This study examines the economic analysis and profitability of honey production and marketing in Cross River State, Nigeria, over 5 years (2017-2021) for sustainable forest management. Six hundred and eighty-four (684) respondents were selected from three ecological zones in the state using …

Assessing Ectomycorrhizal Advantage On Tree Species Within Differing Soil Materials In Spring Mountains, Nevada, Kirsten Soriano, Riley Jones, Daniel Thompson

Undergraduate Research Symposium Posters

Ectomycorrhizal fungi (ECM) form symbiotic relationships with their partner plant, creating root systems which allow for the exchange of nutrients among connected plants. The Spring Mountains National Recreation Area (NRA) in Southern Nevada is the study site for examining ECMs due to its diverse ecosystem with numerous inhabiting species. To assess the effects of ECMs on the tree composition, literature review was conducted to outline previous methods. Through data analysis and observations of the sample sites, it is concluded that ECMs are highly likely to have an effect on tree composition of the Spring Mountains NRA. The purpose of this …

Place, Space, And Shifting Views Of Nature, Rachel Tracey

Runkle Woods Symposia

In her reflective presentation, Rachel Tracy explores her evolving relationship with nature and wilderness. Initially disinterested and uncomfortable in natural settings, she describes how her perspective shifted through class discussions, personal reflection, and immersive experiences in the outdoors. Concepts such as “space versus place” helped her understand the emotional and historical significance of natural environments. Through this journey, she discovered joy in simply being present in nature, ultimately gaining a deeper appreciation for the natural world and its ability to exist and thrive without human involvement.

Culture, Nature, And Reflection: The Settler’S Impact On Life Today, Erin Thomas

Runkle Woods Symposia

Erin Thomas, a senior English major at Wright State University, reflects on the intersection of wilderness, identity, and cultural erasure. Drawing from her Indigenous heritage and experiences in the course Woods and Wilderness, she critiques the romanticized, Eurocentric view of nature as untouched and separate from humanity. Instead, Thomas highlights how wilderness has been shaped by settler colonialism and exclusionary narratives that often ignore Indigenous presence and histories. Her presentation calls for a more inclusive and honest understanding of wilderness—one that honors marginalized voices and acknowledges the land’s complex cultural past.

Wilderness Myth And Reality: Human Views And Uses Of Nature, Evan Hardern

Runkle Woods Symposia

In his essay and presentation, Wright State English major Evan Harder critically examines modern conceptions of wilderness and challenges the Romantic ideal that moral purity and personal virtue are inherently tied to time spent in nature. Drawing on writers such as Wordsworth, Emerson, and Thoreau, Harder interrogates the cultural myth of wilderness as a pristine, untouched realm separate from civilization. He argues that our understanding of nature is a constructed concept—born from the development of cities and agriculture—and often overlooks the long histories of human habitation in places now designated as “natural” or “wild.” Through examples like Cuyahoga Valley National …

The Concept Of Wilderness In Western Culture And Its Sacredness, Shannon Doyal

Runkle Woods Symposia

Shannon Doyal, a Professional Writing student at Wright State, explores how wilderness has been perceived throughout American history—as both a physical space and a powerful spiritual symbol. Drawing from Indigenous perspectives, early settler narratives, Transcendentalist writings, and American literature, she traces the evolving cultural and emotional significance of wilderness. From a place of fear and survival to one of introspection and sacred connection, wilderness reflects our changing relationship with nature and ourselves. As someone whose spirituality honors the cycles of nature, Doyal argues that reclaiming wilderness as a sacred and emotional space is vital—not only for environmental preservation but also …