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 64 for “"forest canopy"”.
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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 influence of epiphytes on arthropods in the tropical forest canopy
… of the extraordinary biodiversity in tropical forests is a major challenge for modern biology. In this context, epiphytes are presumed to play an important role. To investigate the biological reality of this persistent yet insufficiently investigated notion, I conducted the present study. The …
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BEES IN THE WOODS: SPRING ORCHARD POLLINATORS USE FOREST CANOPY POLLEN
… the Northeastern United States is historically forested. Research consistently finds that bee abundance, richness, and crop yields are higher near forests despite their common perception as inhospitable for bees. Inspired by anecdotal reports that bees collect wind-pollinated canopy pollens, we …
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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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Prediction of Foliar Biochemistry in a Boreal Forest Canopy Using Imaging Spectroscopy and LiDAR Data
… and pigments for a boreal mixedwood forest composed of black and white spruce, balsam fir, northern white cedar, white birch, and trembling aspen was investigated. Specifically, imaging spectroscopy (IS) and light detection and ranging (LiDAR) are used to model the foliar N:P ratio, …
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Fluxes of the NO-O3-NO2 triad above a spruce forest canopy in south-eastern Germany
… low NOx concentration levels over large rural forest ecosystems (0.2-10 ppb) are assumed to be important potential counterparts to the high NOx concentration levels over industrialized urban areas (10-1000 ppb). Being able to directly and simultaneously measure the concentrations of the triad …
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Assessing the cumulative impact of disturbance on canopy structure and chemistry in Appalachian forests
Eastern forests experience a range of disturbance events over time, from stand-replacing disturbances, such as clear cuts, to ephemeral disturbances, such as insect outbreaks. By understanding the cumulative impact of disturbances on canopy structure and chemistry, we can gain insight into …
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Absolute localization of mobile robots in forest environments by correlating ground LiDAR to overhead imagery
… the autonomous geolocation of ground vehicles in forest environments is presented. The method provides an estimate of the global horizontal position of a vehicle strictly based on finding a geometric match between a map of observed tree stems, scanned in 3D by Light Detection and Ranging (LiDAR) …
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Field measurement of the fate of atmospheric H₂ in a forest environment : from canopy to soil
… H₂ were made both above and below the forest canopy for over a year using a custom, automated instrument at the Harvard Forest. H₂ fluxes were derived using a flux-gradient technique from the H₂ concentration gradient and the turbulent eddy coefficient. A ten-fold improvement in …
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Erweiterung der `Localized Near Field' Theorie zur Bestimmung von Quellstärken bei beliebiger thermischer Schichtung in einem Waldbestand
… and source/sink profiles inside the plant canopy. This work describes a general method based on the LNF to calculate source distributions from measured concentration profiles inside a plant canopy. The LNF is used for the first time to examine the effects of the so called roughness …
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Variability within the 10-year pollen rain of a seasonal neotropical forest
… and stratification of pollen flow within the forest canopy. Inter-annual variation in pollen rain composition varied most strongly with the preceding year’s precipitation, with a smaller secondary effect of the current year’s temperature and photosynthetically active radiation (PAR). Our …
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Disturbance ecology and size class structure of the Mulanje cedar of Malawi, Widdringtonia whytei and associated broadleaved forest
… size structures in the mixed conifer-broadleaved forests of Mt. Mulanje, Malawi. The size-class structures of the emergent cedar populations were characterised by even-sized, disjunct frequency distributions. Seedling recruitment was found in recently burnt sites and not in middle-aged or …
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Eavesdroppers : how scientists are learning to listen in on the animal kingdom : four stories on wildlife and sound
… like whales in the ocean, elephants under a forest canopy, or birds at night. Sound gives scientists a new way of knowing what is swimming, roaming, and flying where. And some scientists are using these sounds for conservation, to identify the habitats animals need to survive and to protect …
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Modeling the exchange of energy and matter within and above a spruce forest with the higher-order closure model ACASA
… relevant exchange processes above and within a forest canopy. The Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) model incorporates such an advanced turbulence scheme, the third-order turbulence closure. This study presents the application of the ACASA model for a spruce forest at the …
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Throughfall variation in a mixed deciduous forest
… were measured in an uneven-aged, mixed deciduous forest in western Virginia from August 6, 1972 to June 19, 1973. Storms were grouped according to leafy (growing) season and leafless (dormant) season for analysis of gross rainfall and throughfall. Average leafy season throughfall was 78.2 percent …
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The response of Keen's mice populations to riparian restoration treatments on Lyell Island, Haida Gwaii
The complexity of the forest floor in the pacific coastal forest is largely dependent on coarse woody debris and light transmitting though the forest canopy for promoting understory plant growth and diversity. The purpose of my study was to test the importance of coarse woody debris (CWD) and …
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Habitat Use and Spatial Patterns of a Cottonmouth Snake (Agkistrodon Piscivorus Leucostoma) Population and Thermoregulation of Male Cottonmouth Snakes in Southwestern Missouri
… their use of habitat edges and gaps within the forest canopy to accommodate thermal needs during gestation. The thermal preference range (Tset) of four male snakes was determined to be 23.5 - 29.5 oC with a mean temperature of 26.3 oC (+- 0.253). The mean body temperature of field-active males …
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Post-wildfire black carbon deposition on the snowpack in the Cascade Range, Washington State: Temporal and spatial variability with implications for accelerated melt
… accumulation and ablation patterns by decreasing forest canopy and depositing light absorbing impurities (LAI) on the snowpack. LAI such as black carbon (BC), burned woody debris, and dust reduce snow albedo (reflectance), accelerate melt, and affect the timing and availability of water resources. …
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Classification and dynamics of the forest vegetation of Hluhluwe Nature Reserve, Kwa Zulu-Natal
The forests of Hluhluwe Nature Reserve, Kwa Zulu-Natal, were examined to determine composition, grain, classification, dynamics and conservation value. Field sampling took the form of recording DBH for all species in twenty-one 0.04 ha circular plots, walking 5-metre wide transects in mature and …
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