Dissertations / Theses on the topic 'Canopy'
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Medina, Alejandro Josue. "Urban Canopy." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/44892.
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This thesis explores the definition of an urban canopy, how civic architecture can create a space for the pedestrian in the city, and the elements which can compose such a space.
Experimentation in the urban canopy allows definition into the protective nature of such an archetype. Filtering and entrance techniques are discovered to allow access by the pedestrian only. The structural and spatial composition of the space is also developed to enhance human interaction and usability. Layering provides different levels of access and privacy as different groups use the space. And finally the employment of light highlights key elements and creates a presence in the space.
This covering is designed to protect more than just the citizens below. It creates a place that fosters civic community under the a the generous shelter of a new urban institution.Master of Architecture
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Carlyle, Erin. "Magnolia Canopy Otherworld." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1555331993434814.
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Newell, Felicity L. "A Bird’s Eye View of the Forest: How Does Canopy Openness Affect Canopy Songbirds?" The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276875484.
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Noble, Sidney Lake. "The Influence of Canopy Cover and Canopy Heterogeneity on Plant Diversity within Oak Savannas." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1595843486558554.
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Udumala, Savary Sajith Kumar Jose. "Study of the force distribution in the citrus canopy during harvest using continuous canopy shaker." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041324.
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Grant, Eleanor Rose. "Canopy-atmosphere interactions over complex terrain." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550799.
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The study of boundary layer flow through a forest canopy on complex terrain has, until recently, been limited to modelling and laboratory studies. This thesis presents a unique set of field measurements from within and above a canopy situated on a ridge. A climatological study of the observed dataset is presented to identify the significant fea- tures of these flows that differentiate them from air flows above and within a homogeneous canopy on flat terrain. The ridge is found to impact on the flows in the following ways. On the summit the velocity profile resembles that of a canopy profile on flat terrain with little variation in wind.speed below the canopy and an obvious inflection point at the canopy top. On the windward slope, the inflection point disappears. Significant amounts of -u'w' at the canopy top indicates that turbulent mixing acts strongly to transport higher mo- mentum air down into the canopy, which smooths the layer of shear. The profile on the lee slope is dependent on the size of a separation region that can develop on the lee slope of the forested ridge. The direction of the mean wind within the canopy on the lee slope is dependent on the hill-induced pressure gradient, which tends to drive a reversed flow up the lee slope, and on the turbulent mixing which tends to drive the flow down-slope through the mixing of higher momentum air from above the canopy. If the hill slope is sufficiently large (so the pressure gradient is large), or the canopy is sufficiently deep (so that turbulence is unable to mix the higher momentum air all the way to the bottom), then flow separation can occur. Case studies are presented to investigate the formation and development of the separation region on the lee slope of the forested ridge. The presence of a flow separation region is observed to extend the width of the dynamic pressure profile such that, as the separation region expands up the lee slope towards the summit, the minimum is forced back to the upwind edge of the separation region. Large scale separation is observed on the ridge, whereby the separation region extends beyond the top of the canopy. Within the separation region, there is little variation in wind speed or vertical momentum flux with height as the inflection point is elevated to the top of the separation region. Comparisons between the observed case studies and model simulations are made to quan- tify the success of the model at simulating canopy air flows over complex terrain. The model is found to successfully capture the main features the these flows. Areas where the model was less successful are attributed to the inhomogeneous nature of the canopy and the terrain at the field site, and to the low resolution of the model.
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Holland, M. R. "Canopy collapse of dried pea crops." Thesis, University of Edinburgh, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305741.
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Jackson, Robin Geoffrey. "Remote sensing of forest canopy gaps." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327361.
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Cuello, Nerea. "NEW CONCEPT OF A STROLLER CANOPY." Thesis, Tekniska Högskolan, Jönköping University, JTH, Industridesign, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-49442.
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This master thesis report describes the process of designing, developing and building an accessory for a stroller that protects the kid from rain and sun. The project is a collaboration with Thule Sweden AB, in Hillerstorp.The work starts with developing a new concept idea for Thule’s category “Active with kids”, in the line of strollers, and with a focus on the Southern Europe market, more concretely Spain. The design proposal fits and expresses Thule’s vision and brand language.The project started with gaining knowledge about the market, investigating the user needs with surveys to find out the design goals. An iterative process of ideation, brainstorming and building mock-ups ended with a final concept that was going to be further developed. A full-scale model was built to test the idea from the functional and aesthetic perspective. The materials used were mainly fabrics, foam, zippers, thread and a lot of sewing.The result is a new stroller canopy for different weather conditions. It is well equipped to improve parents experience when going out for a ride with their child.It has to be mentioned that this master thesis research section was conducted in pairs, between Berta Cester and Nerea Cuello, and the rest of the phases was an individual work. As a result, two different products were produced for the same category, the stroller market.
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Monteleone, Susan Elaine. "Light Spectra Distributions in Temperate Conifer-Forest Canopy Gaps, Oregon and in Tropical Cloud-Forest Canopy, Venezuela." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc279052/.
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Light spectra distributions were measured in two different montane forests: temperate and tropical. Spectral light measurements were made in different sized canopy gaps in the conifer forest at H. J. Andrews Experimental Forest in Oregon, USA. Researchers at Oregon State University created these
gaps of 20 m, 30 m, and 50 m in diameter. In the tropical cloud forest, spectral light measurements were made in two plots that were permanently established at La Mucuy Parque Nacional in Venezuela, in collaboration with researchers at Universidad de Los Andes. In both studies, spectra and distributions of physiologically active light were analyzed: red, far-red, R/FR ratio, and blue light.
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Balduzzi, Mathilde. "Plant canopy modeling from Terrestrial LiDAR System distance and intensity data." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20203.
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Le défi de cette thèse est de reconstruire la géométrie 3D de la végétation à partir des données de distance et d'intensité fournies par un scanner de type LiDAR. Une méthode de « shape-from-shading » par propagation est développée pour être combinée avec une méthode de fusion de données type filtre de Kalman pour la reconstruction optimale des surfaces foliaires.-Introduction-L'analyse des données LiDAR nous permet de dire que la qualité du nuage de point est variable en fonction de la configuration de la mesure : lorsque le LiDAR mesure le bord d'une surface ou une surface fortement inclinée, il intègre dans sa mesure une partie de l'arrière plan. Ces configurations de mesures produisent des points aberrants. On retrouve souvent ce type de configuration pour la mesure de feuillages puisque ces derniers ont des géométries fragmentées et variables. Les scans sont en général de mauvaise qualité et la quantité d'objets présents dans le scan rend la suppression manuelle des points aberrants fastidieuse. L'objectif de cette thèse est de développer une méthodologie permettant d'intégrer les données d'intensité LiDAR aux distances pour corriger automatiquement ces points aberrants. -Shape-From-Shading-Le principe du Shape-From-Shading (SFS) est de retrouver les valeurs de distance à partir des intensités d'un objet pris en photo. La caméra (capteur LiDAR) et la source de lumière (laser LiDAR) ont la même direction et sont placés à l'infini relativement à la surface, ce qui rend l'effet de la distance sur l'intensité négligeable et l'hypothèse d'une caméra orthographique valide. En outre, la relation entre angle d'incidence lumière/surface et intensité est connue. Par la nature des données LiDAR, nous pourrons choisir la meilleure donnée entre distance et intensité à utiliser pour la reconstruction des surfaces foliaires. Nous mettons en place un algorithme de SFS par propagation le long des régions iso-intenses pour pouvoir intégrer la correction de la distance grâce à l'intensité via un filtre de type Kalman. -Design mathématique de la méthode-Les morceaux de surface correspondant aux régions iso-intenses sont des morceaux de surfaces dites d'égales pentes, ou de tas de sable. Nous allons utiliser ce type de surface pour reconstruire la géométrie 3D correspondant aux images d'intensité.Nous démontrons qu'à partir de la connaissance de la 3D d'un bord d'une région iso-intense, nous pouvons retrouver des surfaces paramétriques correspondant à la région iso-intense qui correspondent aux surfaces de tas de sable. L'initialisation de la région iso-intense initiale (graine de propagation) se fait grâce aux données de distance LiDAR. Les lignes de plus grandes pentes de ces surfaces sont générées. Par propagation de ces lignes (et donc génération du morceau de la surface en tas de sable), nous déterminons l'autre bord de la région iso-intense. Puis, par itération, nous propagerons la reconstruction de la surface. -Filtre de Kalman-Nous pouvons considérer cette propagation des lignes de plus grande pente comme étant le calcul d'une trajectoire sur la surface à reconstruire. Dans le cadre de notre étude, la donnée de distance est toujours disponible (données du scanner 3D). Ainsi il est possible de choisir, lors de la propagation, quelle donnée (distance ou intensité) utiliser pour la reconstruction. Ceci peut être fait notamment grâce à une fusion de type Kalman. -Algorithme-Pour procéder à la reconstruction par propagation, il est nécessaire d'hiérarchiser les domaines iso-intenses de l'image. Une fois que les graines de propagation sont repérées, elles sont initialisées avec l'image des distances. Enfin, pour chacun des nœuds de la hiérarchie (représentant un domaine iso-intense), la reconstruction d'un tas de sable est faite. C'est lors de cette dernière étape qu'une fusion de type Kalman peut être introduiteThe challenge of this thesis is reconstruct the 3D geometry of vegetation from distance and intensity data provided by a 3D scanner LiDAR. A method of “Shape-From-Shading” by propagation is developed to be combined with a fusion method of type “Kalman” to get an optimal reconstruction of the leaves. -Introduction-The LiDAR data analysis shows that the point cloud quality is variable. This quality depends upon the measurement set up. When the LiDAR laser beam reaches the edge of a surface (or a steeply inclined surface), it also integrate background measurement. Those set up produce outliers. This kind of set up is common for foliage measurement as foliages have in general fragmented and complex shape. LiDAR data are of bad quality and the quantity of leaves in a scan makes the correction of outliers fastidious. This thesis goal is to develop a methodology to allow us to integrate the LiDAR intensity data to the distance to make an automatic correction of those outliers. -Shape-from-shading-The Shape-from-shading principle is to reconstruct the distance values from intensities of a photographed object. The camera (LiDAR sensor) and the light source (LiDAR laser) have the same direction and are placed at infinity relatively to the surface. This makes the distance effect on intensity negligible and the hypothesis of an orthographic camera valid. In addition, the relationship between the incident angle light beam and intensity is known. Thanks to the LiDAR data analysis, we are able to choose the best data between distance and intensity in the scope of leaves reconstruction. An algorithm of propagation SFS along iso-intense regions is developed. This type of algorithm allows us to integrate a fusion method of type Kalman. -Mathematical design of the method-The patches of the surface corresponding to the iso-intense regions are patches of surfaces called the constant slope surfaces, or sand-pile surfaces. We are going to use those surfaces to rebuild the 3D geometry corresponding to the scanned surfaces. We show that from the knowledge of the 3d of an iso-intensity region, we can construct those sand-pile surfaces. The initialization of the first iso-intense regions contour (propagation seeds) is done with the 3D LiDAR data. The greatest slope lines of those surfaces are generated. Thanks to the propagation of those lines (and thus of the corresponding sand-pile surface), we build the other contour of the iso-intense region. Then, we propagate the reconstruction iteratively. -Kalman filter-We can consider this propagation as being the computation of a trajectory on the reconstructed surface. In our study framework, the distance data is always available (3D scanner data). It is thus possible to choose which data (intensity vs distance) is the best to reconstruct the object surface. This can be done with a fusion of type Kalman filter. -Algorithm-To proceed a reconstruction by propagation, it is necessary to order the iso-intensity regions. Once the propagation seeds are found, they are initialized with the distances provided by the LiDAR. For each nodes of the hierarchy (corresponding to an iso-intensity region), the sand-pile surface reconstruction is done. -Manuscript-The thesis manuscript gathers five chapters. First, we give a short description of the LiDAR technology and an overview of the traditional 3D surface reconstruction from point cloud. Then we make a state-of-art of the shape-from –shading methods. LiDAR intensity is studied in a third chapter to define the strategy of distance effect correction and to set up the incidence angle vs intensity relationship. A fourth chapter gives the principal results of this thesis. It gathers the theoretical approach of the SFS algorithm developed in this thesis. We will provide its description and results when applied to synthetic images. Finally, a last chapter introduces results of leaves reconstruction
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Perkins, Kelly A. "Cerulean warbler selection of forest canopy gaps." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4596.
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Gao, Jincheng. "Canopy chlorophyll estimation with hyperspectral remote sensing." Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/252.
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Pilger, Neal, and University of Lethbridge Faculty of Arts and Science. "Canopy reflectance modeling of forest stand volume." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2004, 2004. http://hdl.handle.net/10133/230.
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Three-dimensional canopy relectance models provide a physical-structural basis to satellite image analysis, representing a potentially more robust, objective and accurate approach for obtaining forest cover type and structural information with minimal ground truth data. The Geometric Optical Mutual Shadowing (GOMS) canopy relectance model was run in multiple-forward-mode (MFM) using digital multispectral IKONOS satellite imagery to estimate tree height and stand volume over 100m2 homogeneous forest plots in mountainous terrain, Kananaskis, Alberta. Height was computed within 2.7m for trembling aspen and 1.8m fr lodgepole pine, with basal area estimated within 0.05m2. Stand volume, estimated as the product of mean tree height and basal area, had an absolute mean difference from field measurements of 0.85m3/100m2 and 0.61m3/100m2 for aspen and pine, respectively.xiii, 143 leaves : ill. (some col.) ; 29 cm.
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Narayanan, Sruthi. "Canopy architecture and water productivity in sorghum." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8760.
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Master of ScienceDepartment of Agronomy
Robert M. Aiken
Increasing crop water use efficiency (WUE), the amount of biomass produced per unit water consumed, can enhance crop productivity and yield potential. The objective of the first study was to evaluate the factors affecting water productivity among eight sorghum (Sorghum bicolor (L.) Moench) genotypes, which differ in canopy architecture. Sorghum genotypes, grown under field conditions, showed significant differences in (a) biomass production, (b) water use, (c) intercepted radiation, (d) water productivity and (e) radiation use efficiency (RUE; the amount of biomass produced per unit of intercepted radiation which is suitable for photosynthesis). WUE and RUE were more strongly correlated to biomass production than to water use or intercepted radiation, respectively. RUE was positively correlated to WUE and tended to increase with internode length, the parameter used to characterize canopy architecture. These results demonstrate that increased utilization of radiation can increase water productivity in plants. Sorghum canopies that increase light transmission to mid−canopy leaves can increase RUE and also have the potential to increase crop productivity and WUE. The objective of the second study was to develop a quantitative model to predict leaf area index (LAI), a common quantification of canopy architecture, for sorghum from emergence to flag leaf stage. LAI was calculated from an algorithm developed to consider area of mature leaves (leaves with a ligule/collar), area of expanding leaves (leaves without a ligule/collar), total leaf area per plant and plant population. Slope of regression of modeled LAI on observed LAI varied for photoperiod sensitive (PPS) and insensitive (non−PPS) genotypes in 2010. A good correlation was found between the modeled and observed LAI with coefficient of determination (R[superscript]2) 0.96 in 2009 and 0.94 (non−PPS) and 0.88 (PPS) in 2010. These studies suggest that canopy architecture has prominent influence on water productivity of crops and quantification of canopy architecture through an LAI simulation model has potential in understanding RUE, WUE and crop productivity.
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Carr, Daniel. "Non-intrusive load monitoring with canopy clustering." Thesis, University of South Wales, 2012. https://pure.southwales.ac.uk/en/studentthesis/nonintrusive-load-monitoring-with-canopy-clustering(14629d2f-4fdf-47c0-aa3e-9cb7924ce5df).html.
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Dwindling fossil fuels and the rising price of energy has meant that attitudes towards energy usage have changed in both domestic and commercial settings. This change in attitude has led to the development of smart metering technologies that are currently being rolled out across the world. The research has been developed to be able to add functionality to smart metering devices by providing information about energy usage within the premises through Non-Intrusive Load Monitoring (NILM). The thesis provides a detailed description of the work undertaken to develop a novel method of load disaggregation within NILM to aid in the monitoring of energy usage and the provision of consumer feedback which can be integrated into smart metering technologies. The research aims to provide a novel approach to NILM through the use of canopy clustering for its main process of load disaggregation. Canopy clustering provides the necessary tools for separating out appliances and groups of appliances for later classification into individual loads, which brings many benefits compared to other technologies. The research methodology has been developed with robust techniques of data gathering, model development and validation through a rigorous testing approach. Real world examples of loads have been used for the creation and development of the models. The use of contemporary appliances within the research has meant that the NILM algorithm developed is current and usable. In the final implementation it could be commercialised for use by the general public. The full procedures of the algorithm have been explained in detail with the addition of information on the final classification methods that could be used when implemented within smart metering devices. Further work and improvements to the research have also been included for consideration.
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Jenkins, Stuart Rees. "The ecology of sheltered, canopy dominated shores." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481202.
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Edwards, Clinton Lee. "Free-space optical communications through a forest canopy." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1742.
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Thesis (M.S.) -- University of Maryland, College Park, 2004.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Bamatraf, Abdurhman Mohamed. "Temporal and spatial relationships of canopy spectral measurements." Diss., The University of Arizona, 1986. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1986_25_sip1_w.pdf&type=application/pdf.
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Pera, Gizelle M. "Canopy Demographics at the Firestone Reserve, Costa Rica." Scholarship @ Claremont, 2010. http://scholarship.claremont.edu/cmc_theses/707.
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Though Costa Rica has suffered numerous bouts of deforestation to its valuable tropical rainforest area, especially in the 1970s, it has become a leader in its efforts to regenerate and restore its rainforest. However, studies and protocols for the assessment of forest regeneration are urgently required. Research has shown that the percentage of light penetrating the canopy floor, or light fraction, is a good indicator of rainforest maturity. In this study, digital rectilinear photography and a global positioning system receiver were used to survey the Firestone Reserve inCosta Rica in order to measure the light fraction differences between primary/riparian forest, bamboo plantation, secondary hardwood plantation, and natural secondary regrowth. The images were used to calculate light fractions with the software program ImageJ. Using ArcGIS, a kernel density plot was created, along with a map organizing the light fractions in the vegetation types. Significant differences in light fraction were found between bamboo and all other vegetation types, between secondary natural regrowth and secondary hardwood plantation, and between secondary natural regrowth and primary/riparian forest. No significance was noted between primary/riparian and secondary hardwood plantation, or between primary/riparian and secondary forest. Inaccuracies of the study could be due to the high amount of variance, low sample size, or high levels of sunlight that distort the photographs. Nevertheless, the study provided useful information concerning the differences between vegetation types and has implications towards regrowth and recovery of the rainforest.
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Wells, Rachel. "Genetic control of canopy architecture in Brassica napus." Thesis, University of East Anglia, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439928.
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Rowland, Clare Sharon. "Forward and inverse modelling of forest canopy reflectance." Thesis, University of Salford, 2001. http://usir.salford.ac.uk/46521/.
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Fort, Tania. "Functions, transmission and emission of the canopy microbiota." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0338.
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Les arbres interagissent avec des communautés microbiennes diversifiées qui influencent leur fitness et le fonctionnement des écosystèmes terrestres. Contrairement aux micro-organismes associés aux racines et au sol, les micro-organismes qui colonisent la canopée forestière sont encore mal connus. L’objectif de cette thèse est de mieux comprendre les fonctions des micro-organismes associés aux parties aériennes des arbres (feuilles, tiges, graines) ainsi que leur dynamique de transmission verticale (de l’arbre à ses descendants) et horizontale (émission de l’arbre vers l’atmosphère), en combinant des analyses d’écologie moléculaire et d’écophysiologie végétale. Le premier chapitre [P1] montre une stratification verticale des communautés fongiques et bactériennes foliaires au sein de la canopée du hêtre (Fagus sylvatica). Cette stratification est plus marquée chez les micro-organismes épiphytes que chez les endophytes, elle s’atténue au cours de la saison végétative chez les bactéries et semble être liée à la morphologie plutôt qu’à la physiologie foliaire. La stratification verticale des fonctions microbiennes est en cours d’analyse. Le deuxième chapitre [P2] met en évidence la présence de champignons dans les tissus internes des glands du chêne sessile (Quercus petraea), y compris l’embryon, suggérant que le microbiote peut être transmis verticalement de l’arbre mère à ses descendants et influencer la régénération forestière. Les glands contiennent en particulier plusieurs espèces de champignons pathogènes, en association avec leurs mycoparasites. Ces communautés fongiques varient significativement en fonction de l’arbre mère et de la population de chêne. Enfin, le troisième chapitre [P3] teste un prototype de mesure des flux d’émissions bactériennes au-dessus des couverts végétaux. Il montre que la moitié des espèces capturées dans l’atmosphère est présente sur la surface des feuilles et suggère que la composition des bioaérosols est fortement influencée par la plante cultivée dominante localement, la vigne (Vitis Vinifera). Des mesures complémentaires, incluant une plus large gamme d’habitats forestiers et non-forestiers, devront être réalisées pour mieux cerner l’origine des émissions, qui sont connues pour influencer le cycle de l’eau. Cette thèse apporte donc des éléments pour modéliser la dynamique et l’évolution du système arbre-microbiote-atmosphère, qu’il conviendra de renforcer et d’intégrer aux connaissances sur le système sol afin de répondre aux défis posés par le changement climatiqueTrees interact with diverse microbial communities that influence their fitness and the functioning of terrestrial ecosystems. Unlike microorganisms associated with roots and soil, microorganisms that colonize the forest canopy are still poorly understood. The objective of this thesis is to better understand the functions of microorganisms associated with the aerial parts of trees (leaves, stems, seeds) as well as their vertical (from the plant to its offspring) and horizontal (emission from the plant to the atmosphere) transmission dynamics, by combining molecular ecology and plant ecophysiology analyses. The first chapter [P1] shows a vertical stratification of fungal and foliar bacterial communities within the beech canopy (Fagus sylvatica). This stratification is more pronounced for epiphytic microorganisms than for endophytes. It also decreases during the growing season in bacteria and appears to be related to morphology rather than foliar physiology. Vertical stratification of microbial functions is being analyzed. The second chapter [P2] highlights the presence of fungi in the internal tissues of the acorns of sessile oak (Quercus petraea), including the embryo, suggesting that the microbiota can be transmitted vertically from the mother tree to its offsprings and influence forest regeneration. Acorns contain in particular several fungal pathogens, in association with their mycoparasites. These fungal communities vary significantly depending on the mother tree and the oak population. Finally, the third chapter [P3] tests a prototype for measuring bacterial emission fluxes over plant cover. It shows that half of the species captured in the atmosphere are present on the leaf surface and suggests that the composition of bioaerosols is strongly influenced by the locally dominant cultivated plant, the grapevine (Vitis vinifera). Complementary measures, including a wider range of forest and non-forestry habitats, will have to be carried out to better understand the origin of emissions, which are known to influence the water cycle. This thesis therefore provides elements for modelling the dynamics and evolution of the tree-microbiota-atmosphere system, which will need to be strengthened and integrated into knowledge of the soil system in order to respond to the challenges raised by climate change
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Carr, Daniel. "Canopy Disturbance and Reproduction in Cornus florida L." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2245.
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This study examined aspects of local reproductive variation in the flowering dogwood (Cornus florida L.) coincident with recent differences in primary canopy architecture. The dogwood trees in this study were impacted by a hurricane that created numerous treefall gaps, which created fine scale heterogeneity in the primary canopy. Fine scale disturbances in a forest can result in changes for multiple members of the forest community, including the reproductive responses of the trees and interspecific pollination mutualisms. Previously determined differences in offspring genetic structure suggested that pollen movement among genetically unstructured maternal individuals was significantly impacted between open, or disturbed, canopy and closed, or undisturbed, types. To further understand mechanisms by which this nonrandom mating occurred, this study examined both intrinsic and extrinsic reproductive factors for C. florida. The first chapter examines several parameters of the reproductive phenology of sample groups of dogwood between the canopy types as intrinsic factors. The parameters observed included initiation, course and termination of flowering, seed set and seed germination ratios. The results showed some significant differences between the sampling areas in flowering intensity, although the majority of the variation was between maternal individuals throughout the entire sample. The second chapter examines insect community composition across areas of differential canopy disturbance. Community analysis showed that the open canopy contained a larger and more diverse assemblage of insects than the closed canopy or the field, which represented an area of complete canopy removal. This shift in insect community composition may have created functional differences in the local pattern of pollen flow by altering the functional composition of local potential pollinator assemblages. The major finding of this study was that the impact of intermediate natural disturbance on the mating systems of understory plant populations may be more indirect than direct. In conclusion, the observed differences in insect community structure within these habitat types in this study were consistent with predetermined patterns of pollen flow; this structure can explain some of the previously observed genetic structure within locally proximate understory tree populations.
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Monje, Oscar A. "Effects of Elevated CO2 on Crop Growth Rates, Radiation Absorption, Canopy Quantum Yield, Canopy Carbon Use Efficiency, and Root Respiration of Wheat." DigitalCommons@USU, 1993. https://digitalcommons.usu.edu/etd/6763.
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Wheat canopies were grown at either 330 or 1200 μmol mol-1 CO2 in sealed controlled environments, where carbon fluxes and radiation interception were continuously and nondestructively measured during their life cycles. The effects of elevated CO2 on daily growth rates, canopy quantum yield, canopy and root carbon use efficiencies, and final dry mass were calculated from carbon flux measurements in an open gas exchange system. Dry biomass at harvest was predicted from the gas exchange data to within ± 8%. The greatest effect of elevated CO2 occurred in the first 15d after emergence; however, several physiological processes were enhanced throughout the life cycle. Elevated CO2 increased average net photosynthesis by 30%, average shoot respiration by 10%, and average root respiration by 40%. Crop growth rate, calculated from gas exchange data, was 30% higher during both vegetative growth and reproductive growth. Elevated CO 2 did not affect radiation interception, but increased average canopy quantum yield from 0.039 to 0.051 (31%). Average canopy carbon use efficiency was increased by 12%. Although harvest index was unaffected, these increases in the physiological determinants of yield by elevated CO2 resulted in a 14% increase in seed yield.
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Peterson, Birgit Ellen. "Canopy fuels inventory and mapping using large-footprint lidar." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3189.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Geography. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Burlison, Alison Jean. "Sward canopy structure and ingestive behaviour in grazing animals." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/27546.
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Espinoza, Fermin Owens Robb E. "Identifying roads and trails hidden under canopy using Lidar." Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Sep%5FEspinoza.pdf.
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Thesis (M.S. in Science in Space Systems Operations)--Naval Postgraduate School, September 2007.Thesis Advisor(s): Olsen, R. C. "September 2007." Description based on title screen as viewed on October 22, 2007. Includes bibliographical references (p.105-108). Also available in print.
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Larrivée, Maxim. "Diversity of canopy spiders in north-temperate hardwood forests." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115856.
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The objective of this thesis was to understand the spatial patterns and processes responsible for canopy and understorey spider (Arachnida: Araneae) diversity at multiple spatial scales in north-temperate hardwood forests. I sampled tree trunks (sticky traps) and foliage (beating) of sugar maple and American beech tree canopies and their understorey saplings in old growth forests near Montreal, Quebec. Results show the composition of canopy and understorey assemblages differed significantly, and so did sugar maple and American beech canopy assemblages. Each stratum was also dominated by different species. The rank-abundance distribution of species from each habitat wsa also verticaly stratified because it fit different distribution models. Different factors likely structure assemblages in both habitats, particularly since the canopy is a less stable environment. Spiders from canopy and understorey foliage were tested in a laboratory for their propensity to balloon. General linear models indicated that small sized web-building spiders of the RTA and Orbicularia clades have the highest propensity to balloon. Small bodied species initiated ballooning regardless of the habitat they were collected in or their developmental stage. My results support the mixed evolutionarily stable strategy theory and indicate the absence of risk-spreading in the dispersal strategy of canopy spiders. My last chapter focused on dispersal capacity and diversity patterns of spiders at multiple spatial scales. Analyses of the species diversity of limited and high dispersal capacity species subsets through nested-multivariate ANOVA, additive diversity partitioning, and species-abundance distribution curves all point towards species-sorting processes as the main driver of local community spider diversity at the tree and stand spatial scales. Mass-effects and patch-dynamic processes drive site and regional scale diversity patterns. This thesis demonstrates that spiders provide good models to test many biological hypotheses. The research chapters of this thesis test hypotheses on the vertical stratification of forest spider diversity, the evolution of local dispersal adaptations, and the importance of dispersal capacity on species diversity patterns through a metacommunity framework.
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Owens, Robb E. "Identifying roads and trails hidden under canopy using Lidar." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/3329.
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LIDAR data collected from four geographic regions are studied to determine the feasibility of reliably identifying roads and trails hidden under dense jungle and forest canopies. The four analyzed regions include the Elkhorn Slough in Central California (2005), Kahuku Training Area on the North side of Oahu Island in Hawaii (2005), La Selva Biological Station near Puerto Viejo de Sarapiqui, Costa Rica (1997), and Cougar Mountain Park in Bellevue, Washington (2001). Using the commercial product, Quick Terrain Modeler, 3-D interactive analysis was done to identify roads and trails hidden under canopy. Results are compared to overhead panchromatic imagery and verified by significant ground truth. Trails with widths of 2.5 meters and narrower were found with overall accuracies up to 85%.
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Krougios, Prokopios. "Extracting hidden trails and roads under canopy using LIDAR." Thesis, Monterey, California. Naval Postgraduate School, 2008. http://hdl.handle.net/10945/3823.
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The field of Remote Sensing has been greatly benefited by the development of LIDAR. The extraction of bare earth under tree canopies and especially the identification of hidden trails are important tools for military and civilian operations in dense forests. LIDAR data from Sequoia National Park in California (2008) and Fort Belvoir Military Base in Virginia (2007) were two areas that were selected for analysis. Quick Terrain Modeler software was used in order to recognize hidden trails. The entire procedure was followed by ground truth verifications in Sequoia National Park and all the necessary preparations for the analysis of Fort Belvoir data were studied. The ground truth results in Sequoia were promising and the analysis of Fort Belvoir data was encouraging for further development of the system. Trails with a width less than 2 m were easily recognized in Fort Belvoir during the analysis of the data, which affirmed the high accuracy of the sensor. In the Sequoia area, only paved trails with a width less than 1.5 m were identified.
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Luker-Brown, M. "Simulating the interactions between canopy microclimate and vegetation physiology." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299539.
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PAULA, REGINALDO ROSA COTTO DE. "NUMERICAL INVESTIGATION OF FLOW WITHIN AND ABOVE FOREST CANOPY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11570@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICONeste trabalho três métodos foram utilizados para estudar o escoamento turbulento em regiões de florestas. No primeiro método, a influência da vegetação no escoamento foi modelada através da adição de termos fontes nas equações de quantidade de movimento, energia cinética turbulenta e sua taxa de dissipação. No segundo, a vegetação foi considerada um meio poroso homogêneo. Finalmente, a camada do dossel foi representada por modelos 3-D de árvores, consideradas como obstáculos individuais. As equações foram resolvidas através do modelo de turbulência k −E padrão com o programa comercial FLUENT 6.2.16. As previsões dos perfis verticais da velocidade do vento médio, da intensidade da turbulência e dos tensores de Reynolds, foram comparadas com dados de experimentos de túnel de vento. Os resultados preditos dos perfis verticais da velocidade média e intensidade da turbulência, na primeira e na segunda metodologias, apresentaram boa concordância com os valores experimentais, porém, foram observadas discrepâncias nos perfis modelados do tensor de Reynolds. Entretanto, qualitativamente, a modelagem consegue capturar o comportamento físico do tensor de Reynolds no interior de florestas. Uma possível explicação para este fato, é que o modelo considera a isotropia para a viscosidade turbulenta, implicando na incapacidade de prever qualquer forte anisotropia do campo turbulento. Na terceira metodologia, as previsões dos perfis verticais de velocidade média e intensidade da turbulência apresentaram discrepâncias em relação às medições. Porém, os perfis verticais do tensor de Reynolds apresentaram boa concordância. Todos os perfis verticais da velocidade média apresentaram um ponto de inflexão na interface vegetação-atmosfera, característico de uma camada de mistura. Nas duas primeiras metodologias, este padrão foi confirmado nos perfis de tangente hiperbólica de uma camada de mistura.
This work investigates different procedures in order to study the turbulent flow over the scale model of a forest region. Initially, the canopy flow was modeled by using source terms in the momentum, turbulent kinetic energy and its dissipation rate equations. After that, the forest canopy was considered a homogeneous porous medium. In the last step, the canopy boundary layer was modeled by artificial 3-D tree models. This was done by using the standard k−E turbulence model with the FLUENT commercial program. The modeled profiles of mean velocity, turbulence intensity and Reynolds stress were compared against data from wind tunnel experiments. In the two first methodologies, the model predictions of the vertical profiles of the wind speed and turbulence intensity showed good agreement with the experimental data. It was found that predictions of the Reynolds tensor were sensitive to the parameterization scheme of the standard k −E model. However, qualitatively, the model was capable of predicting the physical behavior of the Reynolds stress tensor in the canopy flow. A possible explanation for this behavior is the omission of any anisotropic eddy-viscosity effects within the k - E modelling approach. When it was considered the tree array, the model predictions for the wind speed and turbulence intensity were less satisfactory. However, it was found that the predicted results of the Reynolds stress tensor agreed well with the measured data. All the vertical profiles of the mean velocity contained an inflection point, something which is a necessary criterion for the mixing layer flow. In the tree array, the modeled results failed to the capture this behavior of the canopy flow. In the 2-D numerical simulations, it was found the characteristic hyperbolic tangent profile of a mixing layer.
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Roberts, Anthony. "The influence of acacias on below canopy grass communities." Bachelor's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/26501.
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The influence of acacia species through their varying life stages (seedlings, juveniles, adults and dead trees) on sub-canopy grass communities was investigated at various sites in the Hluhluwe-Umfolozi Park (HUP). There were significant differences between classes (at p < 0.05} to each other and to the open sites, but to differing extents at the different rainfall regions within the HUP. Significant differences occurred between young acacias and the open sites more frequently at the drier sites than at the wetter sites. Young acacias do not influence below canopy grass communities in the high rainfall regions. ln the low rainfall sites, the young acacias act as refugia for 'bunch' grass species in the sea of 'lawn'. A switch back to lawns occur below the adult acacias dominated by the 'lawn' grass Dactyloctenium australe which occurs at differing proportions to the 'bunch' grass Panicum maximum below the canopy depending on the extent of animal disturbance, measured as density of droppings. Rainfall was responsible for separating communities out between the various sites in HUP. However, the impact of animals on the grass communities within each of the sites had more influence on the resulting grass communities in each of the classes. The response of a variety of grass species to light levels failed to explain the presence of particular species below adult acacias and others away from the influence of these acacias. Succession is occurring between grass communities as a result of establishment of acacias with the process being more evident in the dry areas of the HUP. The grass communities in the high rainfall areas revert back to early successional communities more rapidly once a tree dies than they do in the low rainfall areas. The influence of the adult acacias on the below canopy soils is greater and affects grass communities for a longer period of time in thc low rainfall areas than it is in the high rainfall areas even after the tree has died.
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Kimball, Pulelehua L. "Urban Tree Canopy Assessments in the Chesapeake Bay Watershed." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48057.
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An urban tree canopy assessment (UTCA) is a new technology that can inform management decisions to optimize the economic, social and environmental benefits provided by urban forests. A UTCA uses remote sensing to create a comprehensive spatial snapshot of a locality's land cover, classified at a very fine scale (1 meter or less). Over the past decade, UTCAs have been conducted for numerous localities in the Chesapeake Bay watershed (CBW) as part of a strategy to enhance urban tree canopy (UTC) and reduce stormwater runoff that pollutes the Chesapeake Bay. Our research examined how local governments employ these UTCAs and identified barriers to and drivers of UTCA use for urban forest planning and management. We conducted a web-based survey of all localities in the CBW with populations over 2,500 for which a UTCA existed as of May 2013. We found that 33% of respondents reported being unaware that a UTCA existed for their locality. Even so, survey results showed that localities aware of their UTCA were using it to establish UTC goals, create and implement strategies to achieve those goals, and monitoring progress towards UTC goals. Survey localities were segmented based on how they reported using their UTCA to provide insight on possible outreach and technical assistance strategies that might improve future UTCA use. Overall, we found that larger localities with more developed urban forestry programs use their UTCA more frequently. However, we found several exceptions, suggesting that UTCAs could be an important catalyst for expanding municipal urban forestry programs.Master of Science
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Horn, Andrea L. "Assessment of Tree Canopy Effects Overtop Low Volume Roadways." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1564052715480026.
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Teixeira, João Carlos Martins. "WRF sensitivity to lower boundary and urban canopy parametrizations." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/10175.
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Mestrado em Meteorologia e Oceanografia FísicaAo longo dos anos avanços, na tecnologia de satélite viabilizaram a aquisição de informações sobre a superfície da Terra, tais como elevação e uso do solo, com grande detalhe e resolução. Esta informação pode ser incluída em modelos numérico da atmosfera, atualizando e dando-lhes mais detalhes sobre as condições de fronteira inferior. Assim sendo, este trabalho visa estudar a sensibilidade do Weather Research and Forecasting model a três conjuntos de dados de topografia, e dois de uso do solo diferentes. Um caso de estudo em que a precipitação orográfica foi dominante sobre a Ilha da Madeira foi considerado mostrando que, em geral não existe um aumento significativo da performance do modelo ao usar topografia ou uso do solo de alta resolução. Contudo, existe uma melhor performance do modelo em simular a precipitação a barlavento e o fluxo a sotavento da ilha. Dada a natureza deste estudo, considerou-se também um teste à sensibilidade de três parametrizações de microfísica, sendo que os resultados encontrados não mostram alterações significativas aos resultados encontrados. Além disso, a introdução de um novo conjunto de dados de uso do solo tornou possível realizar simulações usando modelos urbanos acoplados. Assim, de forma a estudar a sensibilidade a estes modelos considerou-se um caso de estudo sobre a região de Lisboa. Ao utilizar um modelo urbano verificou-se que sobre a região urbana existe um arrefecimento à superfície quando comparando com as simulações de controlo. Além disso verificou-se uma grande diferença no escoamento e na energia turbulenta produzida sobre esta zona. Estas diferenças podem por sua vez intaragem com ondas gravíticas, alterando a sua fase e amplitude. Além disso, ao comparar os resultados com dados observados verificou-se que, em geral, não existe melhoria na performance do modelo para este caso de estudo. No entanto o uso do modelo urbano BEP melhora significativamente os resultados relativos à altura da camada de mistura.
Through the years, the advances in satellite technology made feasible the acquisition of information about the Earth surface, such as elevation and land use, with great detail and resolution. This information can be included in numerical atmospheric models, updating and giving them more details about the lower boundary. Given so, this work aims to study the sensitivity of the Weather Research and Forecast model to three different topography datasets as well as two different land use datasets. A test case study in which topography driven precipitation was dominant over Madeira Island was considered. Overall, results show that there is no enhancement of model skill when using higher resolution topography or land use. However, there is a higher model skill simulating precipitation on Madeira leeward and wind flow windward. Additionally, given the nature of this event, a sensitivity test was also performed considering three different microphysics parametrizations. This test showed that the choice of the microphysics parametrizations does not significantly change the results found for this event. Furthermore, the introduction of a new land use dataset turned possible to perform simulations using Urban Canopy Models. Therefore, the sensitivity of the model to these urban parametrizations was also performed. In this work, a case study for the Lisbon region was chosen and showed that the simulations that used a urban canopy model presented a cooling in the urban region. Moreover, larger changes were observed for wind flow and turbulence kinetic energy over the area. In addition, it was shown that these could change the phase and amplitude of gravity waves that were generated in the region. When comparing to observed data it was seen that there is no enhancement of model skill when using these models. However, the planetary boundary layer is better represent by BEP urban model.
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Karatolios, Apostolos Krougios Prokopios. "Extracting hidden trails and roads under canopy using LIDAR." Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Dec/08Dec%5FKaratolios.pdf.
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Thesis (M.S. in Applied Physics and M.S. in Applied Physics and M.S. in Electronic Warfare Systems Engineering)--Naval Postgraduate School, December 2008.Thesis Advisor(s): Olsen, R. C. ; Jenn, David C. "December 2008." Description based on title screen as viewed on January 29, 2009. Includes bibliographical references (p. 91-95). Also available in print.
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Pauthenet, Martin. "Macroscopic model and numerical simulation of elastic canopy flows." Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0072/document.
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On étudie l'écoulement turbulent d'un fluide sur une canopée, que l'on modélise comme un milieu poreux déformable. Ce milieu poreux est en fait composé d'un tapis de fibres susceptibles de se courber sous la charge hydrodynamique du fluide, et ainsi de créer un couplage fluide-structure à l'échelle d'une hauteur de fibre (honami). L'objectif de la thèse est de développer un modèle macroscopique de cette interaction fluide-structure, afin d'en réaliser des simulations numériques. Une approche numérique de simulation aux grandes échelles est donc mise en place pour capturer les grandes structures de l'écoulement et leur couplage avec les déformations du milieu poreux. Pour cela nous dérivons les équations régissant la grande échelle, au point de vue du fluide ainsi que de la phase solide. À cause du caractère non-local de la phase solide, une approche hybride est proposée. La phase fluide est décrite d'un point de vue Eulerien, tandis que la description de la dynamique de la phase solide nécessite une représentation Lagrangienne. L'interface entre le fluide et le milieu poreux est traitée de manière continue. Cette approche de l'interface fluide/poreux est justifiée par un développement théorique sous forme de bilan de masse et de quantité de mouvement à l'interface. Ce modèle hybride est implémenté dans un solveur écrit en C$++$, à partir d'un solveur fluide disponible dans la librairie CFD \openfoam. Un préalable nécessaire à la réalisation d'un tel modèle macroscopique est la connaissance des phénomènes de la petite échelle en vue de les modéliser. Deux axes sont explorés concernant cet aspect. Le premier consiste à étudier les effets de l'inertie sur la perte de charge en milieu poreux. Un paramètre géométrique est proposé pour caractériser la sensibilité d'une microstructure poreuse à l'inertie de l'écoulement du fluide dans ses pores. L'efficacité de ce paramètre géométrique est validée sur une diversité de microstructures et le caractère général du paramètre est démontré. Une loi asymptotique est ensuite proposée pour modéliser les effets de l'inertie sur la perte de charge, et comprendre comment celle-ci évolue en fonction de la nature de la microstructure du milieu poreux. Le deuxième axe d'étude de la petite échelle consiste à étudier l'effet de l’interaction fluide-structure à l'échelle du pore sur la perte de charge au niveau macroscopique. Comme les cas présentent de grands déplacements de la phase solide, une approche par frontières immergées est proposée. Ainsi deux méthodes numériques sont employées pour appliquer la condition de non-glissement à l'interface fluid/solide: l'une par interface diffuse, l'autre par reconstitution de l'interface. Cela permet une validation croisée des résultats et d'atteindre des temps de calcul acceptables tout en maîtrisant la précision des résultats numériques. Cette étude permet de montrer que l'interaction fluide-structure à l'échelle du pore a un effet considérable sur la perte de charge effective au niveau macroscopique. Des questions fondamentales sont ensuite abordées, telles que la taille d'un élément représentatif ou la forme des équations de transport dans un milieu poreux soupleWe study the turbulent flow of a fluid over a canopy, that we model as a deformable porous medium. This porous medium is more precisely a carpet of fibres that bend under the hydrodynamic load, hence initiating a fluid-structure coupling at the scale of a fibre's height (honami). The objective of the thesis is to develop a macroscopic model of this fluid-structure interaction in order to perform numerical simulations of this process. The volume averaging method is implemented to describe the large scales of the flow and their interaction with the deformable porous medium. An hybrid approach is followed due to the non-local nature of the solid phase; While the large scales of the flow are described within an Eulerian frame by applying the method of volume averaging, a Lagrangian approach is proposed to describe the ensemble of fibres. The interface between the free-flow and the porous medium is handle with a One-Domain- Approach, which we justify with the theoretical development of a mass- and momentum- balance at the fluid/porous interface. This hybrid model is then implemented in a parallel code written in C$++$, based on a fluid- solver available from the \openfoam CFD toolbox. Some preliminary results show the ability of this approach to simulate a honami within a reasonable computational cost. Prior to implementing a macroscopic model, insight into the small-scale is required. Two specific aspects of the small-scale are therefore studied in details; The first development deals with the inertial deviation from Darcy's law. A geometrical parameter is proposed to describe the effect of inertia on Darcy's law, depending on the shape of the microstructure of the porous medium. This topological parameter is shown to efficiently characterize inertia effects on a diversity of tested microstructures. An asymptotic filtration law is then derived from the closure problem arising from the volume averaging method, proposing a new framework to understand the relationship between the effect of inertia on the macroscopic fluid-solid force and the topology of the microstructure of the porous medium. A second research axis is then investigated. As we deal with a deformable porous medium, we study the effect of the pore-scale fluid-structure interaction on the filtration law as the flow within the pores is unsteady, inducing time-dependent fluidstresses on the solid- phase. For that purpose, we implement pore-scale numerical simulations of unsteady flows within deformable pores, focusing for this preliminary study on a model porous medium. Owing to the large displacements of the solid phase, an immersed boundary approach is implemented. Two different numerical methods are compared to apply the no-slip condition at the fluid-solid interface: a diffuse interface approach and a sharp interface approach. The objective is to find the proper method to afford acceptable computational time and a good reliability of the results. The comparison allows a cross-validation of the numerical results, as the two methods compare well for our cases. This numerical campaign shows that the pore-scale deformation has a significant impact on the pressure drop at the macroscopic scale. Some fundamental issues are then discussed, such as the size of a representative computational domain or the form of macroscopic equations to describe the momentum transport within a soft deformable porous medium
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Thomas, Daniel. "Hitchhiking in the Canopy: Ecological Patterns of Forest Mycobiomes." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23141.
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The fungal microbiome, or “mycobiome” of plants is diverse and important to
host health, but the fluxes of fungi among plant hosts and with the surrounding
environment are poorly understood. In chapter two, we employed sterile culture
techniques and spatial sampling to examine leaves as possible vectors for transfer of their
endophytic fungi from the canopy to substrate on the forest floor, as predicted by the
Foraging Ascomycete hypothesis. Some foliar endophytic fungal species are also present
as wood-decomposing fungi on the forest floor, that transfer of mycelium across these
two life history stages can occur, that endophytic life history stages are buffered from
environmental conditions in comparison to wood-decomposing fungi, and that spatial
linkages between the two life history stages can be observed. In another study, described
in chapter 3, wood and leaf wood endophytes were sampled across a 25 ha plot, to
explore landscape patterns of mycobiomes, and to explore the concept of a core
microbiome in aerial plant tissues. We found that core microbiomes may be observed in a
real ecological setting, but that the concept of core must be carefully defined and that
some level of buffering from disturbance may be necessary to allow core microbiomes to
assemble. In chapter four, we return to examine some of the assumptions and
implications of the Foraging Ascomycete hypothesis, with an agent-based model. We
model the conditions under which dispersal through falling leaves may represent a
fitness-enhancing dispersal strategy for fungi, and that deforestation as is currently
underway throughout the world may have impacts on fungi that rely upon a canopy-
inhabiting life stage for dispersal. In chapter five, some challenges associated with
environmental sampling of microbes using illumina© MiSeq sequences are critically
examined. We find that biases introduced by random sampling at various stages of
IVenvironmental DNA extraction and illumina© MiSeq sequencing are not well corrected
by currently accepted bioinformatic algorithms. In addition, information loss from
differential extraction, PCR amplification, and sequencing success, requires that users of
MiSeq read libraries to interpret read abundances carefully.
This dissertation includes previously published, co-authored material.
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Wang, Wei-Min. "Estimation of component temperatures of vegetative canopy with Vis/NIR and TIR multiple-angular data through inversion of vegetative canopy radiative transfer model." Strasbourg, 2009. http://www.theses.fr/2009STRA6027.
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Les mesures de la température de brillance des couverts végétaux s’appliquent à de très nombreux domaines comme la climatologie, l’hydrologie, l’agronomie, écologie. Son intérêt principal est de permettre d’accéder à l’estimation du bilan énergétique de la surface. Les mauvaises performances des modèles actuels en terme de restitution de la température de surface sont attribuées, en grande partie, à l'hétérogénéité des surfaces continentales. Les modèles actuels sont inaptes à rendre compte correctement des flux dans ces conditions (même éventuellement avec une correction de type kB-1). Les espoirs portent sur les modèles à deux sources qui traitent de façon différente les flux surface/atmosphère pour les sols et pour la végétation. Ce travail a permis de montrer que les paramètres structurels de la végétation comprenant l'indice de superficie foliaire, la distribution d'angle foliaire et l’indice de groupement exercent de grands effets sur la simulation du transfert radiatif dans le couvert végétal, et également sur la séparation des températures composantes du couvert végétal à partir des données multidirectionnelles dans les domaines visible et infrarouge thermique. Ce travail a aussi montré qu’il était possible d’amélioration la séparation des températures composantes du couvert végétal en utilisant la distribution d'angle foliaire et l’indice de groupement obtenus de données satellitaires. Un modèle analytique en tenant compte de la structure de la végétation a été développé et l'architecture optimale du réseau neuronal a été étudiée et proposée pour extraire les températures composantes du couvert végétal à partir des données multidirectionnelles dans les domaines visible et infrarouge thermiqueThe separation of component temperature is the basic step for the application of two-source algorithm. Multi-angular thermal infrared measurements provide a chance for the estimation of component temperatures (namely, soil and vegetation temperatures) with remotely-sensed data. The objective of this study is to explore the factors that affect the estimation of component temperatures and propose new algorithm for inverting the canopy radiative transfer models to compute component temperatures. The objectives of this dissertation include: (1) finding an appropriate candidate leaf angle distribution functions for modeling and inversion, (2) evaluating the scaling behavior of Beer's law and its effect on the estimation of component temperatures, (3) proposing an analytical model for directional brightness temperature at top of canopy, (4) retrieving component temperatures with neural network and simplex algorithms. The effects of leaf angle distribution function on extinction coefficient, which is a key parameter for simulating the radiative transfer through vegetative canopy, is explored to improve the radiative transfer modeling. These contributions will enhance our understanding of the basic problems existing in thermal IR remote sensing and improve the simulation of land surface energy balance. Further work can be conducted to continue the enhancement and application of proposed algorithm to remote sensing images
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Wang, Wei-Min Li Zhao-Liang. "Estimation of component temperatures of vegetative canopy with Vis/NIR and TIR multiple-angular data through inversion of vegetative canopy radiative transfer model." Strasbourg : Université de Strasbourg, 2009. http://eprints-scd-ulp.u-strasbg.fr:8080/00001118.
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Strydom, Janéne. "Canopy manipulation practices for optimum colour of redglobe (V.Vinifera L.) /." Link to the online version, 2006. http://hdl.handle.net/10019/1228.
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Van, der Vyver Marius Lodewyk. "Restoring the biodiversity of canopy species within degraded spekboom thicket." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1564.
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I investigated the return of plant canopy diversity to degraded spekboom thicket landscapes under restoration treatment. I attempted the reintroduction of five nursery propagated and naturally-occurring plant species in severely degraded Portulacaria afra Jacq. (spekboom) dominated thickets that have been subjected to a restoration method involving the planting of dense rows of P. afra truncheons for various time periods and also in degraded and intact thickets. I also planted nursery propagated P. afra cuttings. An average of 30 propagules of each species, were planted in each of the chosen areas in two distinct seasons that exhibited distinct rainfall peaks. Sixteen propagules of P. afra were also planted in each treatment only once. Propagules of the two thicket woody canopy species (S. longispina and P. capensis) showed a total survival of 1% and 9%, respectively. Survival of L. ferocissimum and R. obovatum was 19% and 70% and all propagules of P. afra survived. Analyses showed that survival is primarily tied to a species effect, with R. obovatum and P. afra showing significantly better survival than the other species. Within the other surviving few species a significant preference for overhanging canopy cover was observed. The results show little significance of restoration treatment for propagule survival, suggesting that a range of conditions is needed for the successful establishment of canopy species that likely involves a microclimate and suitable substrate created by canopy cover and litter fall, combined with an exceptional series of rainfall events. I found that the high costs involved with a biodiversity planting endeavour, and the low survival of propagules of thicket canopy plant species (P. afra excepted), renders the proposed biodiversity planting restoration protocol both ecologically and economically inefficient. Restoration success involves the autogenic regeneration of key species or functional groups within the degraded ecosystem. Heavily degraded spekboom-dominated thicket does not spontaneously regenerate its former canopy species composition and this state of affairs was interpreted in terms of a state-and-transition conceptual model. Floristic analyses of degraded, intact and a range of stands under restoration treatment for varying time periods at two locations in Sundays Spekboomveld revealed that the stands under restoration are progressively regenerating canopy species biodiversity with increasing restoration age, and that intact sites are still the most diverse. The high total carbon content (TCC) measured within the older restored stands Rhinosterhoek (241 t C ha-1 after 50 years at a depth of 50 cm) rivals that recorded for intact spekboom thickets, and the number of recruits found within older restored sites rivals intact sites sampled. 2 The changes recorded in the above- and belowground environments potentially identify P. afra as an ecosystem engineer within spekboom dominated thickets that facillitates the build-up of carbon above- and belowground and the accompanying changes in soil quality and the unique microclimate aboveground, which enables the hypothetical threshold of the degraded state to be transcended. This restoration methodology is accordingly considered efficient and autogenic canopy species return was found to be prominent after a period of 35-50 years of restoration treatment.
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Krayenhoff, Eric Scott. "A multi-layer urban canopy model for neighbourhoods with trees." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51674.
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Over 50% of the world’s population lives in cities, many of which are hot, polluted, and expanding. The design of cities impacts local meteorology and climate, which affect building energy use and the comfort and health of urban residents. Numerical models that incorporate the relevant urban elements and physical processes can predict these effects and guide management strategies.
Addition of vegetation is a key design strategy for moderation of local urban climate, and many cities already boast extensive vegetation. Relative to shorter vegetation, urban trees have unique effects on local climate and pollutant dispersion: they provide shade and shelter, interacting with buildings and streets to alter climate and wind flow.
Urban canopy models (UCMs) predict neighbourhood-scale (10² – 10⁴ m) energy exchange and climate of atmospheric layers between and above the buildings. Few UCMs represent the urban canopy with multiple layers, which permit more flexible and process-based representation of canopy physics. Most UCMs neglect vegetation, or incorporate it with a separate model, neglecting interaction between vegetation and built elements.
This dissertation develops BEP-Tree, the first multi-layer urban canopy model that explicitly includes trees and their interaction with buildings. It consists of an existing multi-layer UCM, a foliage energy balance model, and two major developments: firstly, a model that distributes solar and infrared radiation amongst tree foliage, road, roof, and wall elements at multiple heights, accounting for radiation ‘trapping’ and mutual shading; secondly, parameterization of building and tree foliage effects on flow, including generation and dissipation of turbulence, drag on the mean wind, and explicit consideration of sheltering. The combined model permits a range of building and tree configurations, and makes possible advanced assessment of impacts of trees on urban climate, air quality, human comfort and building energy loads.
BEP-Tree is compared with measurements from the Sunset neighbourhood in Vancouver, Canada. Urban trees channel sensible heat into latent heat (evaporation), shift surface-atmosphere energy exchange upwards, slow canopy wind, and dissipate turbulence, especially if taller than nearby buildings. Effects of trees on canopy thermal climate depend on representation of neighbourhood-scale foliage clumping in radiation versus dynamical processes, and further theoretical advances are required.Arts, Faculty of
Geography, Department of
Graduate
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Gaige, Elizabeth. "Throughfall Dynamics and Canopy Processes in a Nitrogen Fertilized Forest." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/GaigeES2005.pdf.
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Hastwell, Graeme. "Facilitation and fertile islands : linking canopy effects with plant interactions /." Title page, contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phh3588.pdf.
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Costa, Carlos. "Root and canopy characteristics of maize types with extreme architectures." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36898.
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Studies of corn root morphology, canopy description, light and nutrient relationships, have focused on conventional corn hybrids. We are now extending these studies to other corn types with contrasting canopy and root architectures. Field and greenhouse experiments were carried out in order to characterize root morphology, N status in the plant and its relationship with yield and yield components, canopy architecture and light interception of these genotypes. The indoor experiments investigated root morphology and how N affects it. Root fractal geometry and its relationship with standard measured root variables were investigated. The field research, at two sites and over two growing seasons, examined (i) maize canopy architecture with regard to light interception and (ii) nitrogen effects on grain yield of different maize genotypes. Four genotypic types were included: (i) Leafy reduced-stature, Lfy1rd1 (LRS), (ii) non Leafy-reduced stature, lfyrd1 (NLRS), (iii) Leafy normal stature, Lfy1Rd1 (LNS), and (iv) conventional commercial hybrids, lfy1Rd1. Pioneer 3905 served as the check hybrid for late maturity, and Pioneer 3979, the check for early maturity. The work allowed development of following methods: (i) root sampling for measurement of large root systems, (ii) staining to enhance root contrast for measurement with a scanner-based software system, (iii) sample size determination for SPAD meter readings, and (iv) the design and construction of a mobile and multi-strata device for measurement of light interception. Data were collected for mathematical characterization of canopies (i.e. leaf angle, co-ordinates of the maximum height of the leaf, co-ordinates of the leaf tip), plant N status (SPAD meter readings), light interception, yield and grain yield components. Conventional hybrids generally showed greater root length and surface area than their leafy genotypic counterparts at early developmental stages (i.e. up to 15 days from emergence). However, Leafy geno
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Pegoraro, Emiliano. "Environmental control of isoprene emission : from leaf to canopy scale." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/767.
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Isoprene is the most abundant volatile organic compound (VOC) emitted from vegetation, mainly trees. Because it plays an important role in tropospheric chemistry leading to formation of pollutants and enhancing the lifetime of the greenhouse gas methane, concern about the response of isoprene emissions to the rise in atmospheric CO2 concentration and global climate change has been increasing over the last few years. The consequences of predicted climate change will have complex repercussions on global isoprene emission. The increasing atmospheric CO2 per se will have direct effects on terrestrial vegetation since CO2 is the substrate of photosynthesis. Because photosynthesis is limited by CO2 at current ambient concentrations, an increase in CO2 is expected to increase leaf biomass (i.e. isoprene emitting surface). Predicted warmer climate, extended drought periods, the possible shift in plant species in favour of isoprene emitters and the increase in length of growing season, may cause an increase in global isoprene emissions with profound perturbations of air quality and the global carbon cycle. The aim of this thesis was to investigate the effect of environmental variables such as light, temperature, drought and leaf-to-air vapour pressure deficit (VPD), and the short- and long-term effect of atmospheric [CO2] on isoprene emission from temperate and tropical tree species. Both leaf and whole ecosystem level fluxes were studied. At the leaf scale, a short-term experiment with leaves of potted two-year old trees of Quercus virginiana was carried out, exposing plants to two drying-rewatering cycles. Leaf isoprene emission fell, but the process was considerably less sensitive to water stress than photosynthesis and stomatal conductance. In drought conditions, the large reduction in photosynthesis caused the percentage of fixed carbon lost as isoprene to increase as plants became more stressed, reaching peaks of 50% when photosynthesis was almost zero. Isoprene emissions also showed a strong negative linear relationship with pre-dawn leaf water potential (psi-leaf). In another experiment carried out at the large enclosed facility of Biosphere 2 (B2L, Arizona, USA), studying isoprene emission from leaves of three-year-old plants of Populus deltoides grown at three CO2 atmospheric concentrations (430, 800 and 1200 mu mol mol-1 CO2) in non-stressed conditions, instantaneous increases in atmospheric [CO2] always resulted in a reduction of isoprene emission and a stimulation of photosynthesis. Moreover, in the long-term, the CO2 inhibition effect for isoprene emission became a permanent feature for plants growing under elevated [CO2]. Again, isoprene emission was less responsive to drought than photosynthesis. Both water-stress and high VPD strongly stimulated isoprene emission and depressed photosynthetic rate as a result of stomatal closure and the resulting decreases in intercellular [CO2] (Ci). This also led to a dramatic increase in the proportion of assimilated carbon lost as isoprene. The effect of atmospheric elevated [CO2] and its interaction with high VPD and water stress on ecosystem gross isoprene production (GIP) and net ecosystem exchange of CO2 (NEE) in the Populus deltoides plantations was also studied. Although GIP and NEE showed a similar response to light and temperature, NEE was stimulated by elevated CO2 by 72% and depressed by high VPD, while GIP was inhibited by elevated CO2 by 58% and stimulated by high VPD. Similar to what was observed at leaf level, under water stress conditions GIP was stimulated in the short term and declined only when the stress was severe, whereas NEE started to decrease from the beginning of the experiment. This contrasting response led the percentage of assimilated carbon lost by the ecosystem as isoprene to increase as water stress progressed from 2.5% and 0.6% in well-watered conditions to 60% and 40% for the ambient and the elevated CO2 treatments, respectively. Again, we found water limitation and high VPD off-set the inhibitory effect of elevated CO2, leading to increased isoprene emissions. The effect of a mild water stress on GIP and gross primary production (GPP) was also observed in the model tropical rainforest mesocosm of B2L. Although GPP was reduced by 32% during drought, GIP was not affected and correlated very well with both light and temperature. The percentage of fixed C lost as isoprene tended to increase during drought because of the reduction in GPP. Consumption of isoprene by soil was observed in both systems. The isoprene sink capacity of litter-free soil of the agroforest stands showed no significant response to different CO2 treatments, while isoprene production was strongly depressed by elevated atmospheric [CO2]. In both mesocosms, drought suppressed the sink capacity, but the full sink capacity of dry soil was recovered within a few hours upon rewetting. In summary, elevated CO2 increased biomass production and photosynthesis while depressing isoprene production. However, both drought and VPD may off-set the CO2 effect and lead to enhanced isoprene emission. We conclude that the overall effect of global climate change could be of enhancing global isoprene emissions while depressing the soil sink, and that the soil uptake of atmospheric isoprene is likely to be modest but significant and needs to be taken into account for a comprehensive estimate of the global isoprene budget.
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Harmon, Charles F. "Automating identification of roads and trails under canopy using LiDAR." Thesis, Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/5585.
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Approved for public release; distribution is unlimitedAnalysis techniques are developed to automatically extract roads and trails under thick forest canopy. LiDAR data were taken over the Swanton Pacific Ranch in the Santa Cruz Mountains from an airborne laser mapping system, the Optech 3100, on March 9-10, 2010. Collected data were characterized by point densities of 5-10 m2. Point cloud data were reduced to digital surface models using ARCMAP (from ESRI). The DSM was calculated at 1 meter spacing. These surface models were analyzed using topographic tools in ENVI, allowing for calculation of curvature, slope, convexity, and shaded relief. A multi-layer dataset was built and analyzed using spectral analysis tools in ENVI. The classification technique used was a combination of maximum likelihood classifier and a decision tree after use of erosion/dilation operators. Results are compared to ground truth collected in 2011. Classification resulted in 83.6% true positive rate, and the image processing result reduced the false positive rate to 3.0%.