Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"Forest canopies"”.
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Rainfall redistribution and change of water quality in tropical forest canopies : patterns and persistence
… During the passage of rain water through a forest canopy two main processes take place. First, water is redistributed; and second, its chemical properties change substantially. The rain water redistribution and the brief contact with plant surfaces results in a large variability of both …
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Assessing ice storm damage to hardwood forest canopies using the Advanced Solid-State Array Spectroradiometer (ASAS) and Landsat TM imagery
… in January 1998 damaged 17 million acres of forestland in the Northeastern United States and Quebec Province. In July 1998 the airborne multiangle hyperspectral sensor, Advanced Solid-State Array Spectroradiometer (ASAS), acquired imagery for nine ice damaged target areas in the White …
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DISTRIBUTED ENERGETICS OF BOREAL FOREST SNOWMELT
The energetics of snowmelt under boreal forest canopies in central Saskatchewan were examined with respect to the influence of forest canopy structure on the snow cover depletionrate. The distribution of snow water equivalent was examined prior to melt and during melt in five distinct boreal forest …
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The Polarimetric Impulse Response and Convolutional Model for the Remote Sensing of Layered Vegetation
… model to compute the radar backscatter from forest canopies. Several models attempt to predict the backscatter coefficient for random forest canopies by using the Vector Radiative Transfer (VRT) Theory with success, however, these models often rely on purely time-harmonic formulations and …
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Multi-trophic Biodiversity Increases with Increasing Structural Complexity of Forest Canopy
<p>Understanding the effects of forest canopy structural complexity on multi-trophic diversity is critical for conserving biodiversity and managing land sustainably. But multi-trophic diversity is often ignored when making decisions about land management due to lack of cost- and time-effective …
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Fine Characterization of Leafing Phenology in the Brazilian Atlantic Forest by Optical and Microwave Remote Sensing
<p>Tropical forests provide important ecosystem functions in the global biosphere, but they remain among the most poorly understood elements of land surface models, especially with regard to their seasonal dynamics. For instance, in seasonally dry forests, the pattern of the annual green-up in …
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Building A Mechanistic Understanding Of Biodiversity And Ecosystem Functioning In Forests
… trees living in the area. I studied trees in a forest biodiversity experiment at different spatial and temporal scales using remote sensing, leaf-level physiological measurements, and soil analyses. First, I found that fast-growing, early successional tree species created a buffered microclimate …
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Using Airborne Laser Altimetry to Characterize Surface Fuels in Western Montana
Quantifying surface fuels in forests is problematic for land managers due to the difficulty in measuring fuels of different sizes and spatial variability. Estimating fuel loads is important for identifying departures from historical fire regimes, predicting fire behavior and effects, and …
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Using Airborne Laser Altimetry to Characterize Surface Fuels in Western Montana
Quantifying surface fuels in forests is problematic for land managers due to the difficulty in measuring fuels of different sizes and spatial variability. Estimating fuel loads is important for identifying departures from historical fire regimes, predicting fire behavior and effects, and …
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Modeling Forest Canopy Distribution from Ground-Based Laser Scanner Data
… ground-based laser scanner was used to assess forest canopies and measure individual tree parameters. The instrument is comparable to scanning airborne light detection and ranging (lidar) technology but gathers data at higher resolution over a more limited scale. The raw data consist of a …
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The effects of grass invasion and fire severity on Acacia koa regeneration
… grass so that land managers can increase their forested landscapes’ fire resilience. One challenge to this line of inquiry is that remotely-sensed data often fails to accurately measure grass cover underneath forest canopies. The 2018 Keauhou Ranch Fire in Hawaiʻi presents an opportunity to …
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Understory Composition, Seedling Growth, and Snag Frequency Across a Water-Limited Forest Landscape
… more uncertain. These changes can affect forest plant communities directly by altering demographic rates, and indirectly through interspecific interactions. Impacts can vary among forest strata. Here, I asked how different forest strata respond to topographic variation in soil moisture and …
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Mediterranean forest resilience to drought and climate change
… the tools needed to quantify the resilience of forests to drought and evaluate the effectiveness of management plans remain limited. This thesis examines how freely available satellite data can be used to quantify changes in forest canopies in response to climate variability. Using a combination …
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Terrestrial laser scanning to characterise three-dimensional foliage and woody material distributions in trees
… of foliage and wood distribution within forests is essential for understanding, managing and monitoring forest ecosystems. The recent advances in terrestrial laser scanning (TLS) technologies have provided new opportunities to measure the 3D structure of forest canopies, which in turn can …
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Thermal Evaluation of an Urbanized Watershed using SWMM and MINUHET: a Case Study of Stroubles Creek Watershed, Blacksburg, VA
… by reducing albedo, and increased vegetation canopies. An index titled Percentage of Time Temperature Exceeded 21°C Threshold (PTTET) for trout habitat was used to represent the effectiveness of thermal mitigation practices. Installing concrete pavement (thermal diffusivity: 15×10-7 m²/s, …
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Forest structure in unharvested old-growth: understanding the influence of soils on variability of long-term tree dynamics and fire history
Western North American forests adapted to frequent fires have been fundamentally altered and fragmented as a result of fire exclusion, the transportation infrastructure, development patterns, and other landscape level changes. In order to enhance the resiliency, diversity, and productivity of …
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Biosphere-Atmosphere Exchange of Peroxyacetyl Nitrate: Development of a Flux Measurement System and its Application on a Grassland Ecosystem
… is preferably used above high vegetation such as forest canopies. Due to large errors of the HREA application, this thesis presents a detailed analysis of the effects of an imprecise sampling of up- and downdraft events for REA applications. Especially, the implication of a long inlet tube may …
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Urban Restoration Ecology: Investigating environmental change, ecological function, and enrichment planting
… with long development timelines, such as forests, it is unclear how dynamics change after planting and over the long-term, and hence what best management practices should be used in the decades following initial plantings. This thesis addresses these knowledge gaps through three separate …
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Snowfall Interception and Ablation in Needleleaf Canopies: Observations and Model Development
Snow falls on forests covering 23% of the global landmass. Here, interception by forest canopies plays a crucial role in the terrestrial water cycle and land-atmosphere energy exchanges. Global changes in climate and vegetation cover have the potential to alter how snowfall is intercepted and …
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