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Articles 1 - 7 of 7
Full-Text Articles in Forest Sciences
Influence Of Silvicultural Treatment, Site Characteristics, And Land Use History On Native And Nonnative Forest Understory Plant Composition On The Penobscot Experimental Forest In Maine, Elizabeth Bryce
Electronic Theses and Dissertations
This study investigates forest understory plant diversity and composition in managed and unmanaged stands within the context of a long-term silvicultural experiment in the Acadian Forest of Maine. I examined the effects of silvicultural intensity and past land use on understory plant species diversity and composition. Silvicultural treatments include three variants of the selection system, three variants of the shelterwood system, modified and fixed diameter-limit cutting, and an unregulated harvest. Two types of unmanaged stands were studied: a continuously forested natural area and secondary forest stands on old fields. Chapter 1 presents analysis of understory plant diversity and composition in …
The Chemistry Of Acidic Soils In Humid, Temperate Forested Watersheds With Emphasis On Phosphorus, Aluminum And Iron, Micheal Sanclements
The Chemistry Of Acidic Soils In Humid, Temperate Forested Watersheds With Emphasis On Phosphorus, Aluminum And Iron, Micheal Sanclements
Electronic Theses and Dissertations
Acidification of soils can result from natural processes (i.e. pedogenesis) and from atmospherically derived sulfur (S) and nitrogen (N) which originate from anthropogenic emissions. Research on the effects of acidification has typically focused on base cations, N and aluminum (Al). The Bear Brook Watershed in Maine (BBWM) (a long-term, whole-watershed acidification experiment) demonstrated increased episodic stream export of Al, iron (Fe), and phosphorus (P) in the treated watershed, suggesting that acidification can also affect P. This research evaluates (a) the physical and chemical distribution of P, (b) mechanisms controlling soil P accumulation, mobilization, and availability in humid, temperate forested ecosystems, …
Soil Amino Acids At Upper Tree Line, Montane And Lower Tree Line, Kelly C. Owens
Soil Amino Acids At Upper Tree Line, Montane And Lower Tree Line, Kelly C. Owens
Electronic Theses and Dissertations
The classic view of the nitrogen cycle in soils is for plants to take up inorganic N in solution for N nutrition. More recent studies reveal plants can take up low molecular weight dissolved organic N such as amino acids directly from the soil. In ecosystems where the rate of microbial mineralization is limited, plants may take up 10 to 200 percent more amino acid N than mineral N. It is not known if plants take up amino acids in all ecosystems, however recent research shows that plants generally take up amino acids when they are present in high quantities …
A Case Study Approach For Assessing Operational And Silvicultural Performance Of Whole-Tree Biomass Harvesting In Maine, Charles E. Coup
A Case Study Approach For Assessing Operational And Silvicultural Performance Of Whole-Tree Biomass Harvesting In Maine, Charles E. Coup
Electronic Theses and Dissertations
In the Northeastern United States, re-emerging markets for renewable energy are driving interest in increasing the harvest of underutilized biomass material from Maine’s forest. These markets may offer opportunities for forest managers to implement silvicultural treatments that have previously been foregone due to their high cost. However, many operational challenges arise in using current harvesting systems to harvest biomass material profitably while simultaneously achieving silvicultrual objectives. This research uses a case study approach to analyzing some of the possibilities and obstacles in implementing biomass harvesting in Maine. The first three studies investigate a factorial silvicultural and operational case study involving …
Development Of A Ligno-Cellulosic Polymeric And Reinforced Sheet Molding Compound (Smc), Ryan Harris Mills
Development Of A Ligno-Cellulosic Polymeric And Reinforced Sheet Molding Compound (Smc), Ryan Harris Mills
Electronic Theses and Dissertations
The overall objective of this dissertation was to study the surface energy and acid-base characteristics of natural fibers, glass, a wood extract, and a sheet molding compound prepreg to facilitate the fabrication of totally synthetic and partially renewable sheet molding compounds (SMCs). The water absorption and micro-mechanical performance of the totally synthetic and partially renewable SMC composites were compared through accelerated aging experiments. Reinforcing glass sized for polyester, bast kenaf fibers, hot water extract from Acer rubrum, and a dicyclopentadiene modified polyester prepreg were analyzed by inverse gas chromatography to evaluate and help predict how the various components may interact …
The Influence Of Hot Water Extraction On Physical And Mechanical Properties Of Osb, Juan Jacobo Paredes Heller
The Influence Of Hot Water Extraction On Physical And Mechanical Properties Of Osb, Juan Jacobo Paredes Heller
Electronic Theses and Dissertations
The finite reserves of petroleum are driving renewed interest in technologies that allow for sustainable production of energy. There are a wide variety of technologies with well-developed infrastructure like the oriented strand board (OSB) industry, which could be used as launch point for developing biorefineries. The effects of hot water extraction (HWE) on two hardwood species (Acer rubrum, Populus tremuloides) and softwood species (mixture of southern yellow pine, Tsuga canadensis) were studied. The HWE resulted in a weight loss (WL) that increased as the severity factor (SF) was extended. Hardwood had the biggest WL values at equivalent extraction conditions. The …
The Influences Of Conventional And Low Density Thinning On Leaf Area, Growth, And Growing Space Relationships Of Eastern White Pine (Pinus Strobus L.), Christopher Henry Guiterman
The Influences Of Conventional And Low Density Thinning On Leaf Area, Growth, And Growing Space Relationships Of Eastern White Pine (Pinus Strobus L.), Christopher Henry Guiterman
Electronic Theses and Dissertations
Despite the commercial importance and widespread management of eastern white pine {Pinus strobus L.) in the Northeast, surprisingly little is known about the effects of thinning on even-aged stand development. To address this, patterns of leaf area, bole form, volume growth, and growth efficiency - defined as volume increment per unit leaf area - were examined over a 17-year period within a thinning study in central Maine designed to compare the conventional B-line and low density thinning regimes. At the tree-level, many of the effects of thinning were as expected. Heavier, low density thinning resulted in significantly larger and deeper …