Life Sciences Commons^™

Targeted Browsing With Goats For Eastern Redcedar (Juniperus Virginiana L.) Control, Alanna M. Hartsfield

Electronic Theses and Dissertations

As eastern redcedar (ERC) (Juniperus virginiana L.) grassland encroachment progresses, all potential control methods should be explored in the interest of Great Plains grassland health and longevity. Targeted browsing with goats has been proven as an effective control method on some juniper species; however, little is known about its ability to control ERC. These studies intend to mend knowledge gaps of how targeted browsing with goats control ERC by causing tree death without chemicals or machinery. The first study is two 3x3 Latin squares comparing protein-supplemented diets. The second study is a randomized complete block design of five 0.224 ha …

Eastern Redcedar (Juniperus Virginiana L.) Encroachment On South-Central South Dakota Rangelands: Impact On Plant Communities, Austin K. Domeier

Electronic Theses and Dissertations

Grasslands historically covered 46 million km2 of Earth’s surface representing nearly 42% of the living vegetation. Encroachment of woody species onto grasslands and savannas is a widely researched global phenomenon, with eastern redcedar (ERC) (Juniperus virginiana L.) trees being the most prominent woody encroacher in the Northern Great Plains (NGP) due to the lack of prescribed fire and planted ERC escaping from shelterbelts. This encroachment poses a threat to native plant communities in terms of their reproduction, regeneration, and diversity. ERC are fierce competitors and can establish in most soil types, are drought tolerant, and prolific seed reproducers. These qualities …

Soil Organic Carbon In Maine, Its Responses To Biochar Addition, And Climate Change, Xue Bai

Electronic Theses and Dissertations

Soil organic carbon (SOC), as one of the largest C pools in terrestrial ecosystems, plays a key role in governing soil ecosystem processes and climate regulation. Climate change concerns have resulted in a rapidly growing interest in understanding the potential for natural climate solutions (NCS) that include enhancing SOC sequestration and reduce net atmospheric greenhouse gas (GHG) emissions. This research focused on addressing information needs about SOC in Maine, specifically in evaluating available soil databases to accurately quantify SOC density and concentration, and study the response of selected representative Maine soils to biochar amendments under a changing climate.

Maine SOC …

Economics And Operational Decision Constraints Of Small-Diameter Tree Harvesting, Libin Thaikkattil Louis

Electronic Theses and Dissertations

Sustainably managed forests are crucial in balancing trade-off between various ecosystem functions and optimum product utilization. Improving the utilization of these renewable resources through diversified forest wood products faces various socio-economic, ecological, and cultural challenges. A major challenge faced by forest managers in the Northeastern United States is overstocked stands dominated by small-diameter trees (SDT). Major woody portion of the harvested residues is constituted by SDT and are typically of low value. Data from the national inventory indicates a high number of SDT in Northeastern forests such that the average size of all trees in the region is less than …

Utilization Of Secondary Processing Mill Residues In Maine To Produce Raw Materials For Manufacturing Wood-Plastic Composites (Wpcs), Geeta Pokhrel

Electronic Theses and Dissertations

The overall objective of this study was to explore the potential of utilizing secondary processing mill residues generated in Maine (1.6 million tons annually) in Wood-Plastic Composites (WPCs). Attributable to the huge shipping costs for transporting wood flour over long distances, wood pellets are explored as alternative feedstock for WPCs manufacturing. The mill residues from four species based on their abundance and potential applicability for utilization in WPCs manufacturing were used to make the two different feedstocks. The properties of the wood flour and pellets were studied along with the comparison of the properties of polypropylene-based WPCs using both of …

Seasonal Flammability Comparisons Of Native And Exotic Plants In The Post Oak Savannah, Blackland Prairie, And Pineywoods Ecoregions Of Texas, Michael Tiller

Electronic Theses and Dissertations

East Texas’ diverse landscape can present year-round wildfire seasons that can be influenced by seasonal and regional differences in climate and physiography. Greater insight into the fundamental thermal behavior of wildland fuels can aid in fire behavior prediction and development of fire-resistant plant lists. This study focused on estimating seasonal and regional flammability characteristics of five evergreen species: yaupon (Ilex vomitoria), Chinese privet (Ligustrum sinense), greenbrier (Smilax spp.), eastern red cedar (Juniperus virginiana), and escarpment live oak (Quercus fusiformis); and two deciduous species: Chinese tallow (Triadica sebifera) and southern …

Natural Regeneration Dynamics And Survival Influenced By Abiotic And Biotic Factors In A Bottomland Hardwood Forest, Lydia J. Voth Rurup

Electronic Theses and Dissertations

Riparian ecosystems are vital to the landscape, providing critical services including water filtration and purification, flood and erosion control, carbon sequestration, biodiversity support, and aesthetic value. Bottomland hardwood forests, however, are threatened by invasive species, land loss/conversion, inconsistent or absence of harvesting disturbances, and altered hydrological patterns, leading to reduced success of desired, native species. This research assessed regeneration dynamics and one-year survival in a seasonally-flooded bottomland hardwood forest at Boggy Slough Conservation Area in East Texas to identify abiotic and biotic factors important for successful establishment of native regeneration. Areas sampled included two that were previously treated with herbicide …

Assessing Freezing Effect On Kiwifruit Cultivars And Mapping Suitable Areas For Growing The Crop In Eastern Texas, Lais De Oliveira Machado

Electronic Theses and Dissertations

Kiwifruit is a perennial vine originating from China where it has been grown for centuries. In the United States, green kiwifruit (Actinidia deliciosa) is primarily produced commercially in California. They are fuzzy, green fleshed and well known in the marketplace. Kiwifruit plants require low to moderate soil pH, adequate winter chilling and adequate precipitation to guarantee plant development and good fructification. Actinidia chinesis or golden kiwifruit are smooth skinned, feature golden flesh and are a more recent introduction into the global market. Kiwifruit crops have attributes that favor production in east Texas, including low pest problems, current long …

Forest Disturbance And Occupancy Patterns Of Carnivores: Results Of A Large-Scale Field Study In Maine, Usa, Bryn E. Evans

Electronic Theses and Dissertations

Understanding trends in the abundance and distribution of carnivores is important at global, regional and local scales due to their ecological role, their aesthetic and economic value, and the numerous threats to their populations. Carnivores in Maine range from the American black bear (Ursus americanus), to numerous native mesocarnivore species, such as American marten (Martes americana), fisher (Pekania pennanti), coyote (Canis latrans), red fox (Vulpes vulpes), bobcat (Lynx rufus), Canada lynx (Lynx canadensis) and to two small weasel species (Mustela erminea and Neogale frenata). …

Cellulose Nanofibril Coated Bio-Based Composites For Food Serving Applications, Rakibul Hossain

Electronic Theses and Dissertations

Cellulose nanofibrils (CNFs) and lignin-containing cellulose nanofibrils (LCNFs) have excellent binding properties with lignocellulosic materials such as wood particles, cellulose fibers, and other particles. They also have excellent oil and grease barrier properties. A novel application by utilizing the binder and barrier properties of CNF and LCNF has been proposed. In this study, multi-layer oil-resistant food serving containers were made using cellulose nanofibril coated wood flour composites. Composites were made with different formulations by using LCNF from old corrugated containers (OCC) at different fines content and CNF at 20, 30, and 40% binder content combined with wood particles. LCNF and …

Understanding The Adhesion Mechanism In Mycelium-Assisted Wood Bonding, Wenjing Sun

Electronic Theses and Dissertations

The increasing environmental awareness has led to an increased interest in developing more sustainable materials as alternatives to petroleum-derived products. Among different nature-based products, fungal-mycelium-based bio-composites have gained considerable attention in various applications. Multiple materials with different densities and structures and potential applications can be fabricated by inoculating filamentous white-rot fungi in lignocellulosic materials and other substrates. Different from lower-density as-grown foam-like mycelium composites, higher-density mycelium-lignocellulosic panels have the potential to replace commercial particleboard and fiberboard bonded by petroleum-based resins. This kind of composite can be produced by directly adding heat and pressure to the low-density foams or by assembling …

Remote Sensing Identification Of Black Ash (Fraxinus Nigra) In Maine Via Hyper- And Multi-Spectral Imagery, John W. Furniss

Electronic Theses and Dissertations

North American ash species (Fraxinus spp.) are under dire threat from the invasive pest, emerald ash borer (Agrilus planipennis, EAB). Black ash (F. nigra) has shown no resistance to EAB while its cultural and ecological importance render it irreplaceable. Traditional field forestry techniques are not suitable for the large-scale identification of individual black ash trees to facilitate conservation, thus necessitating the need for other identification and classification techniques. The objective of this research is to develop remote sensing techniques that can be used to identify ash trees, in particular black ash, at the individual tree level using both hyperspectral and …

Tree Responses To Moderate And Extreme Drought In The Northeastern United States, Ruth A. Van Kampen

Electronic Theses and Dissertations

Climate change is expected to lead to novel drought conditions in the Northeastern United States. Therefore, experimental studies that mimic these conditions are crucial to understand the potential impact on forests. Further, recent large scale dendrochronological studies suggest that spring and summer droughts may immediately impact tree growth while fall droughts may cause delayed impacts on growth the following growing season. Therefore, in this study, we investigated the impacts of six-week-long spring, summer, and fall droughts on the physiology and intra-annual growth on 288 saplings of six tree species native to the Northeastern United States. These species (deciduous broadleaf angiosperms, …

Forest Phenology In Maine: Trends And Drivers Over The Past Two Decades And Implications For Resource Managers, Valeria Briones

Electronic Theses and Dissertations

Rapid climate change in recent decades has impacted forest, coastal, and social systems globally. In the northeastern U.S., alterations to the seasonal timing and duration of phenology cycles are a direct result of increasing temperatures, and monitoring these changes serves as a valuable indicator to analyze the impacts of climate change. Furthermore, increasing temperatures can influence when and how visitors recreate in natural landscapes. In the past decade, outdoor spaces have seen an increase in the number of visitors, partly as a result of climate change, that has influenced how resource managers and tourism suppliers plan for and respond to …

Climate Change And Forest Management Impacts On Tree Growth And Physiology, Kelly French

Electronic Theses and Dissertations

Projected changes in temperature and precipitation are expected to lead to declines in many forest tree species across the Northeastern United States. Red spruce (Picea rubens) and balsam fir (Abies balsamea) are two of the most common tree species in Maine that make up about 5.5 million acres of the state’s forest land. As such, future climate conditions pose a major challenge for management of these species, and it is unclear how management may mitigate or exacerbate the negative effects of climate change. Therefore, in this study we investigated how thinning to release suppressed red spruce influences understory microclimate, and …

Community Structure And Dynamics Of Benthic Macroinvertebrates In A Recreated Headwater Stream System On A Valley Fill In A Retrofitted Watershed Located In The Appalachian Coalfields Of Southeastern Kentucky (U.S.A.), Steven W. Bailey

Electronic Theses and Dissertations

The extraction of coal from steep-gradient surface mining sites such as in the Appalachian Coalfields of the U.S. produces excess debris that is often placed in adjacent valleys resulting in the creation of valley fills. Not only are headwater streams buried in the process, but watershed functions are either destroyed outright, or become fragmented and disconnected from adjacent ecosystems resulting in adverse effects to downstream biological communities. In this dissertation, the dynamics of stream macroinvertebrate community structure, composition, diversity, and biotic integrity are assessed at a “proof of concept” stream system recreated on a retrofitted valley fill. For comparison, two …

The Effects Of Prescribed Burning On Soil Water Infiltration Rates And Other Select Soil Physical And Chemical Properties In East Texas, Cassady Pennington Dunson, Brian P. Oswald, Kenneth Farrish, Tyson Hart

Electronic Theses and Dissertations

This study focused on whether prescribed burning affects soil physical and chemical properties, especially water infiltration, in Western Gulf Coast forests. Soil water infiltration rates were measured 1) pre-burn (before the fire), 2) post-burn (one month after the fire), and 3) at vegetation green-up (three months after the fire). Soil samples were also collected to determine the effects of prescribed burning on soil pH, bulk density, particle density, pore space, soil strength, O-horizon weight and depth (organic matter), water stable aggregates, and soil fertility. This project was conducted on two different burn intervals. The National Forests and Grasslands of Texas …

Food-Web And Functional Trait Community Structure Of Predator Assemblages In Pine Forests Under Different Management Regimes, Connor Adams

Electronic Theses and Dissertations

Anthropogenic activities can alter natural disturbance regimes in ecosystems, and thereby affect the structure and function of biological diversity. As many of the world’s ecosystems are degraded beyond natural recovery, well-defined restoration goals are necessary to maintain the ecological processes that provide valuable ecosystem services. Utilizing taxonomic, functional, and food-web approaches, I investigated the impacts of forest management practices in structuring predator communities in two pine forest systems of eastern Texas. The results of this study indicate that the increased frequency of forest management practices such as prescribed fires and thinning operations encourages predator diversity while increasing functional and trophic …

The Ecological Resilience Of A Tropical Montane Pine Forest To Droughts, Fire, And Hurricane Disturbance, Daniel Erland Brugger Swann

Electronic Theses and Dissertations

Owing to the geographic isolation and unique climatic conditions which occur in tropical montane forests (TMFs), these systems are highly sensitive to changes in both climate and disturbance. Therefore, as ongoing climate change alters disturbance regimes – potentially facilitating multiple disturbance interactions much greater than that of isolated disturbances – TMFs may be shifted to alternate stable states. However, study of TMF resilience is essentially unknown given the lack of long-term studies in these systems. We address the resiliency of the tropical montane pine forests of the Cordillera Central, Dominican Republic using long-term climate records, remeasured vegetation data, and reconstructed …

The Future Of Maine's Forests Under Alternative Socioeconomic, Climate And Conservation Pathways, Jianheng Zhao

Electronic Theses and Dissertations

Maine is a historically important timber supply region in North America and understanding the potential change in forestlands and their product industries affected by climate change and various socio-economic conditions can better improve the forest healthy and sustain a sustainable product industry. A statistical harvest choice model for the state of Maine was developed in chapter 1. It was estimated using a multinomial logit model of two products, under varying management intensities, and ownership classifications across varying market conditions. Results indicate that stumpage prices have a significant effect on forest landowners' harvest decisions and that the expansion of conservation land …

Microsite Requirements For Successful Regeneration In Lowland Northern White-Cedar (Thuja Occidentalis) Forests, Jeanette Allogio

Electronic Theses and Dissertations

Declines in stands of northern white-cedar (Thuja occidentalis L., hereafter cedar) have been observed as both shifts in species composition and reductions in cedar densities, particularly those stands in lowland sites (Curtis 1946, Boulfroy 2012). While several factors inhibiting cedar regeneration have been identified, a thorough understanding of the conditions that best promote regeneration is lacking. Our objectives for the first chapter were to characterize the site conditions associated with successful regeneration in lowland cedar stands and to describe how spatial patterns of various cedar size classes relate to site preference and to regeneration dynamics. These objectives were achieved …

Past, Current, And Future Potential Distributions Of Red Spruce And Fraser Fir Forests In The Southern Appalachians: Interpreting Possible Impacts Of Climate Change, Danika Mosher

Electronic Theses and Dissertations

Spruce-Fir forests are relicts from the Pleistocene and can only be found within the Southern Appalachians. Analyzing the relationships between species distribution, climatic parameters, topography, and biotic interactions through ecological niche modeling creates prediction maps for conservation efforts. Maxent, Boosted Regression, and Random Forest were utilized to compare which model and variable combinations best approximate the unique mountain forest environment. Maxent with a bias file produced optimal results and was used to examine distributional changes that may occur in the future and how these changes compare to paleo-environmental distributions. Fraser fir has shown evidence of being influenced by changing climates …

Airborne Hyperspectral Data Application In Stress Detection Of Blueberry Fields And Ash Trees, Catherine Chan

Electronic Theses and Dissertations

Water management and irrigation practices are persistent challenges for many agricultural systems. Changing seasonal and weather patterns impose a greater need for understanding crop deficiencies and excesses (e.g. water, sunlight, nutrients) for optimal growth while allocating proper resources for prompt response. The wild blueberry industry is at heightened susceptibility due to its unique growing conditions and uncultivated nature. Early detection of stress in agricultural fields can prompt management responses to mitigate detrimental conditions including drought and disease. Remote sensing has provided timely and reliable information covering large spatial extents, while novel applications in hyperspectral data and imaging spectroscopy have shown …

Fostering Climate Change Resilience: A Socio-Ecological Forest Systems Approach, Alyssa R. Soucy

Electronic Theses and Dissertations

As climate change continues to impact socio-ecological systems, those that rely on natural resources are highly sensitive to climatic changes. Maine’s forest industry provides for the economic and social well-being of many residents and is especially vulnerable to climate change impacts. Changes in growing season length and timing, forest health threats imposed by insects and pathogens, extreme weather events, shifting forest composition, and changes in natural disturbance severity and frequency have already begun, and are projected to continue, to impact forest systems in the Northeastern U.S. While climate change presents a threat to forest systems, opportunities also arise due to …

Exploring The Social Effects Of Increased Hiker Use At The Northern Terminus Of The Appalachian Trail, Leah Beck

Electronic Theses and Dissertations

The increase of tourism and outdoor recreation popularity has produced a field of research revolved around the social and environmental impacts of visitors. Past research has shown that understanding visitor use and behavior is essential for influencing management strategies. This study focused on understanding the crowding perceptions and experiences of hikers who summit Maine’s tallest mountain, Mount Katahdin. Katahdin is designated as the northern terminus of the Appalachian Trail (AT) which has seen a notable increase in use from long distance hikers in the last 25 years. Increased long-distance AT hikers, and documented issues with hiker behavior in Baxter State …

The Influence Of Environmental Variables On The Height Growth Of Loblolly Pine (Pinus Taeda) In The Western Gulf, Osakpamwan Edo-Iyasere

Electronic Theses and Dissertations

Understanding the effects of environmental factors on stand growth is important in optimizing forest management plans. This study investigated the effects of soil and climate factors on the height growth (site index) of loblolly pine (Pinus Taeda L.) using data collected from permanent plots established in intensively-managed plantations across East Texas and Western Louisiana. The Chapman-Richards model was selected as the base model to describe the height-age relationships and important soil and climate variables were incorporated into the models as model parameter coefficient adjustors. Our results showed that the most important factors for predicting site index were nitrogen …

Simulated Mine Land Reclamation Impact On Biomass Partitioning And Nutrient Contents In Loblolly Pine, Osarumen Egharevba

Electronic Theses and Dissertations

Forest productivity on reclaimed mine land is hindered by soil compaction. Different techniques have been used to alleviate the effect of compaction to various degrees of success. The Forestry Reclamation Approach (FRA) was developed in the Appalachians and has been used to improve forest productivity on reclaimed mines in this region. The FRA provides a step by step method designed to reduce compaction, control erosion, provide land stabilization and accelerate forest succession. This method had not been evaluated in the Gulf Coastal Plain, where the pan scraper reclamation method is commonly used. However, using pan scrapers increases mine soil compaction …

Subalpine Forest Tree Seedling Response To Drought, Alex Goke

Electronic Theses and Dissertations

Knowledge of tree species’ ability to tolerate drought is necessary to anticipate future forest dynamics with climate change, especially at the seedling stage given their role in shaping forest structure. We used precipitation reduction shelters to mimic drought for subalpine conifer seedlings (A. lasiocarpa and P. engelmannii) in the Rocky Mountains and compared survivorship and morphological and physiological responses to assess relative degrees of drought tolerance. We detected no significant investment in morphological tolerance traits (e.g. root biomass, leaf:stem area ratio) but substantial reductions in net photosynthesis. While shading partially ameliorated drought effects when precipitation reduction was moderate, …

Spruce Budworm Defoliation Dynamics And Its Influence On The Acadian Forest, Cen Chen

Electronic Theses and Dissertations

Spruce budworm (SBW; Choristoneura fumiferana (Clem.)) is the primary forest defoliator in North America. SBW defoliation has affected tens of millions ha of forests during its periodic outbreaks and caused severe growth reduction and mortality of spruce-fir (Picea-Abies) species. Evaluating these damaging effects of SBW defoliation requires understandings of the variation and dynamics of defoliation, as well as trees' variable responses to defoliation in consideration of various tree- stand-, and site-level factors. In this dissertation, we developed statistical models to 1) evaluate influences of SBW defoliation on spruce-fir stand dynamics of annual volume net growth, mortality, …

Long-Term Study Of Prescribed Fire Effects On Stand Dynamics And Oak Regeneration Potentials In Degraded Upland Oak-Hickory Stands In Northwestern Arkansas, Mason C. Danheim, Kathryn R. Kidd Dr, Hal O. Liechty Dr, Brian P. Oswald Dr

Electronic Theses and Dissertations

Upland oak-hickory forests in the Ozark Mountains of northwestern Arkansas and south central Missouri were impacted by oak decline during the early 2000s. This decline event was caused by predisposing (e.g., mature, dense stand conditions), inciting (i.e., drought), and contributing (e.g., red oak borer, E. rufulus H., outbreak) factors. Immediately following onset of the decline, substantial crown dieback and tree mortality, particularly for two red oak species (northern red oak, Quercus rubra Michx. and black oak, Q. velutina Lam.), were observed. In addition, densities of advanced oak regeneration were inadequate at this time, resulting in poor regeneration potentials for …