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Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry Aug 2023

Climate Interactions Drive Tree Physiology And Growth In A Northeastern Forest Ecotone, Alexandra M. Barry

Electronic Theses and Dissertations

Climate change is a threat to global forest ecosystems. In the northeastern United States, forest trees are facing rising temperatures and increasingly inconsistent moisture regimes. In addition to long-term changes in climate conditions, there is concern about the potential for more frequent and intense climate extremes, which can have severe and rapid negative effects on tree physiology and growth. Further, climate extremes may co-occur to produce a greater magnitude of effect than the sum of their parts, with a prominent example being hot droughts, which are increasing in occurrence and severity. The impact of these and other extreme climate interactions …


Long-Term Influence Of Commercial Thinning On Spruce-Fir Forests, Bishnu H. Wagle Mr. Aug 2023

Long-Term Influence Of Commercial Thinning On Spruce-Fir Forests, Bishnu H. Wagle Mr.

Electronic Theses and Dissertations

This study investigates long-term influences of pre-commercial thinning (PCT) and commercial thinning (CT) treatments in spruce-fir forests, a key forest type in northeastern North America. Utilizing repeated measurements from replicated experimental research sites (n=15) in Maine, both stand- and tree-level responses to contrasting CT with and without prior PCT (NoPCT) have been quantified. In addition, an in-depth economic analysis, exploring the impact of different thinning treatments, associated costs, merchantability specifications, varying timber and carbon prices, and discount rates, on net present value (NPV) has been carried out using both measured and projected data. Thinning treatments at nine PCT sites combined …


Deconstructing The Art Of Physical Weed Control, Jordan W. Parks May 2023

Deconstructing The Art Of Physical Weed Control, Jordan W. Parks

Electronic Theses and Dissertations

Farmers adjust physical weed control (PWC) tools to optimize efficacy based on observations of weeds, the crop, and soil conditions. These many variables make PWC research challenging. To study PWC tool settings more closely, we constructed a soil bin with a mobile tool carriage inside of a heated glasshouse. The soil bin was 2 m wide by 12 m long by 1 m high, with a tool carriage that can operate at 0.4 to 19.0 km h-1. Tool angle, spacing, depth, and speed can all be precisely adjusted from the tool carriage and control panel. The goal of …


Influence Of Biochar As A Soil Amendment On Soil Water Content And Wild Blueberry Physiology, Abigayl Novak May 2023

Influence Of Biochar As A Soil Amendment On Soil Water Content And Wild Blueberry Physiology, Abigayl Novak

Electronic Theses and Dissertations

Maine wild (or lowbush) blueberries (Vaccinium angustifolium Ait.) continue to face challenges imposed by climate change. Reduced frequency of precipitation and increased drought conditions have negatively impacted this crop since it resides in sandy soils with limited retention of water and nutrients. The wild blueberry plants growing in water- and nutrient-poor sandy soils are likely to have poor resilience to drought, resulting in a decline in berry yield during drought years. Thus, there is an urgent need to find a drought management solution for wild blueberries. Compared with other drought management practices, such as irrigation systems, mulching, and adopting drought-resistant …


Factors Affecting Apothecia Production And Primary Infection By Monilinia Vaccinii-Corymbosi On Vaccinium Angustifolium, Ian Leonard May 2023

Factors Affecting Apothecia Production And Primary Infection By Monilinia Vaccinii-Corymbosi On Vaccinium Angustifolium, Ian Leonard

Electronic Theses and Dissertations

Mummy berry, caused by Monilinia vaccinii-corymbosi (MVC), is a prolific disease of Vaccinium angustifolium (wild blueberry) leading to decreased yield in wild blueberry fields throughout the Downeast (DE) and Midcoast (MC) regions of Maine (ME). This study aimed to identify factors affecting primary inoculum production and infection by MVC on wild blueberry, and what bud stages of wild blueberry are most susceptible to infection. Through common garden (CGE), field and incubation experiments conducted in 2021 and 2022, factors affecting carpogenic germination of MVC pseudosclerotia and relationships between susceptible wild blueberry buds and environmental factors were analyzed. The CGE conducted in …