Remote sensing provides methods to infer vegetation information over large areas at a variety of spatial and temporal resolutions that is of great use for terrestrial carbon cycle modeling. Understory vegetation and foliage clumping in forests present a challenge for accurate estimates of vegetation structural information. Multi-angle remote sensing was used to derive and refine new information about the vegetation structure for the purpose of improving global leaf area index mapping. A field experiment with multi-angle, high resolution airborne observations over modified and natural backgrounds (understory, moss, litter, soil) was conducted in 2007 near Sudbury, Ontario to test a methodology for the background reflectivity retrieval. The experiment showed that it is feasible to retrieve the background information, especially over the crucial low to intermediate canopy density range where the effect of the understory vegetation is the largest. The tested methodology was then applied to background reflectivity mapping over conterminous United States, Canada, Mexico, and Caribbean land mass using space-borne Multi-angle Imaging SpectroRadiometer (MISR) data. Important seasonal development of the forest background vegetation was observed across a wide longitudinal and latitudinal span of the study area. The previous first ever global mapping of the vegetation clumping index with a limited eight-month multi-angular POLDER 1 dataset was expanded by integrating new, complete year-round observations from POLDER 3. A simple topographic compensation function was devised to correct negative bias in the data set cause by topographic effects. The clumping index reductions can reach up to 30% from the topographically non-compensated values, depending on terrain complexity and land cover type. The new global clumping index map is compared with an assembled set of field measurements, covering four continents and diverse biomes. Finally, inclusion of the new vegetation structural information, including background reflectivity and clumping index, gained from the multi-angle remote sensing was then shown to improve the performance of LAI retrieval algorithms over forests.

Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 174-204).

En milieu agricole, on observe depuis plusieurs décennies une régression des prairies ainsi qu’uneévolution de leur mode de gestion liées à l’intensification de l’agriculture. Face aux enjeux que ces changementsimpliquent tant sur le plan environnemental qu’économique, l’estimation de la place des prairies dans les systèmes de production et la détermination des pratiques agricoles qui leur sont associées sont stratégiques. Avec l’arrivée de nouveaux capteurs de télédétection à Haute Résolution Spatiale (HRS) caractérisés par une résolution temporelle élevée, il est désormais possible d’envisager l’étude des couverts prairiaux à une échelle fine et à partir d’observations régulières dans le temps. L’objectif de cette thèse est d’identifier les couverts prairiaux à l’échelle des territoires agricoles et de déterminer leurs modes de gestion à partir de paramètres dérivés de séries temporelles d’images de télédétection à HRS. Pour cela, plusieurs séries intra–annuelles d’images à haute résolution spatiale optiques et radars ont été constituées afin de recenser les prairies et d’identifier trois de leurs modes de gestion : le pâturage, la fauche et l’exploitation mixte, sur un bassin versant dont le système d’exploitation dominant est l’élevage laitier. Les résultats obtenus à partir du traitement et de l’analyse des séries temporelles optiques ont permis de montrer qu’il est possible d’estimer avec une bonne précision la biomasse des prairies, de les identifier et de les caractériser. Ils mettent aussi en évidence le fait que les images radars améliorent l’identification des prairies sans pouvoir discriminer leurs modes de gestion, l’utilisation combinée des deux types d’images augmentant encore le taux d’identification des prairies. Par ailleurs, les résultats montrent que les méthodes de classification s’appuyant sur des critères de comparaison adaptés aux séries temporelles (distances élastiques) produisent des résultats nettement plus satisfaisants pour discriminer les modes de gestion des prairies que les méthodes de classification standards. / In agricultural areas, we observed a decrease of grasslands and change in their management in the last half–century, which are commonly associated with agriculture intensification. These changes have affected environmental and economic systems. In this context, the evaluation of grassland status and grassland management in farming systems is a key–issue for sustainable agriculture. With the arrival of new Earth observation sensors with high spatial and temporal resolutions, it is now possible to study grasslands at fine scale using regular observations over time. The objective of this thesis is to identify grasslands and their management practices using parameters derived from time–series of high spatial resolution (HSR) remote sensing data. For that purpose, several intra–annual time series of HSR optical and Synthetic Aperture Radar (SAR) satellite images were acquired in order to identify grasslands and three of their management practices: grazing, mowing and mixed management, on a catchment area mainly oriented towards cattle production. Results obtained from the processing and analysis of the optical time series have shown that it is possible to estimate with good accuracy grassland biomass, to identify and to characterize them. They also highlighted that radar images improve grassland identification without being able to distinguish management practices, the combined use of the two types of images further increasing grassland identification. Furthermore, results showed that the classification methods based on comparison criteria adapted to time series (warping criteria) increase significantly results for discriminating grassland management practices compared to standard classification methods

Understanding how structure and function change across environmental gradients is a fundamental goal of ecology, with important applications in a changing world. In this dissertation, I explore how environmental variations in temperature and precipitation affect three-dimensional canopy structure, and how this, in turn, affects forest function. Characterising how climatic variations affect forest structure and function is particularly important in tropical forests, which are globally important carbon stores that have already shown vulnerability to climate change. The future of tropical forest carbon stocks is highly uncertain, with plant physiological responses representing the largest source of model uncertainties. As such, my dissertation research comprises empirical investigations into how tropical forests will respond to high temperatures and drought. Firstly, I examine tropical forest response to high temperature by conducting a comparison of natural forest sites and a tropical forest mesocosm using eddy-covariance data. I present evidence that high temperature declines in tropical forest photosynthesis are not due to direct temperature effects (i.e., that cause damage to the photosynthetic machinery), but instead are predominantly due to indirect temperature effects that result from concurrent increases in vapour pressure deficit (VPD). While both mechanisms reduce photosynthesis, the impact of increased VPD under future climate may be partly mitigated by enhanced water-use efficiency associated with rising atmospheric CO2 concentrations, suggesting that tropical forests may have opportunities for resilience in the face of global warming. The second part of my dissertation research examines how tropical forest canopy structure responds to seasonal dry periods and anomalous droughts on seasonal and interannual timescales, using data from ground-based LiDAR (Light Detection and Ranging). I show that total leaf area index (LAI) does not represent the seasonality of forest structure, since the upper and lower canopy levels exhibit divergent seasonal responses. The seasonal pattern of upper canopy LAI shows good agreement with the seasonal pattern of enhanced vegetation index (EVI) measured from satellites, suggesting that satellites are not capturing the response of the lower canopy. These results indicate that smaller trees are responding to seasonal water limitations and larger trees to light availability. I found that the response of canopy structure to anomalous (El Niño-induced) drought was similar to seasonal dry periods, but that the trends in LAI and vertical canopy structure were amplified. In particular, I document a delayed loss of LAI from the upper canopy following extreme drought, which supports the idea that while smaller trees may be more responsive to shorter, less severe dry periods, larger trees are more susceptible to prolonged or more severe droughts. Finally, I combine a long-term ground-based LiDAR dataset with tree inventory data in order to identify the mechanisms (i.e., changes in leaf area and/or woody biomass) of structural changes caused by droughts. I present evidence that loss of lower canopy LAI following an El Niño-induced drought was due to the mortality of small trees, not loss of leaf area, while an increase in LAI in the upper canopy predominantly resulted from plastic leaf area changes. If small trees are susceptible to drought-induced mortality and the incidence of droughts increases, this could prevent the recovery of tropical forests from drought-induced disturbances.

A principal função da arborização viária, nos últimos 30 anos, passou de apenas estética para promotora de serviços ambientais, mas essas árvores estão submetidas a diversos fatores estressantes, como a poluição do ar, a baixa disponibilidade de água, solo compactado, podas severas, e área de crescimento limitada. As redes aéreas de distribuição de energia são um dos elementos que mais interferem no manejo das árvores viárias, pois o conflito, geralmente, já está estabelecido e as concessionárias de energia optam por podas drásticas, que podem comprometer a sanidade da árvore e estimular brotações epicórmicas que crescem rapidamente e vão de encontro com as fiações. Posto isso, o presente estudo teve como objetivo determinar a taxa de crescimento de brotações epicórmicas após poda executada pela Companhia Paulista de Força e Luz (CPFL) em indivíduos das espécies tipuana (Tipuana tipu (Benth.) Kuntze), ipê-roxo (Tabebuia heptaphylla (Vell.) Mart.), e chapéu-de-sol (Terminalia catappa L.), na cidade de Piracicaba/SP e relacionar esta taxa com as características da árvore e do meio. Para isso, foi realizado levantamento em campo de variáveis como a espécie, diâmetro à altura do peito (DAP), índice de área foliar (IAF), tipo de calçada, tipo de solo, fotos do canteiro e dos brotos ao lado de uma baliza para posterior medição digital, que teve sua confiabilidade testada e aprovada nesta pesquisa. A análise foi executada com todas as espécies juntas, para cada espécie, e por classe de DAP dentro de cada espécie. O índice de crescimento médio diário para a tipuana foi de 0,360 cm; para o ipê-roxo, 0,298 cm; e para chapéu-de-sol, 0,404 cm. Houve diferença significativa entre a taxa de crescimento da espécie chapéu-de-sol e ipê-roxo, indicando que a espécie e o grupo sucessional a qual pertencem influenciam no ritmo de crescimento. Não foi constatada influência do tipo de calçada e nem do tipo de solo. O IAF também não influenciou no crescimento, a não ser em ipês com DAP entre 50 e 60 cm. A dimensão do canteiro não influenciou o crescimento dos brotos de chapéu-de-sol, mas influenciou positivamente tanto as tipuanas com 60 a 70 cm de DAP, que foram as árvores com o maior ritmo de crescimento da espécie, como os ipês com DAP entre 30 e 40 cm que ainda estão vigorosos e suas raízes continuam explorando o solo. Os estudos com essa temática são poucos e fatores como clima, época de poda e histórico de manejo da área podem exercer influência na resposta da árvore à poda. Portanto, é sugerido maior tempo de estudo com os mesmos indivíduos e a inclusão de mais árvores. / The main function of the street trees, in the last 30 years, had been switched from aesthetic to the promotion of environmental services. However, this trees are submitted to a lot of stressful factors like limited growth aerea, air pollution, low water availability, compacted soil and drastic pruning. Aerial power networks distribution are the elements that most interfere with the management of street trees, because the conflict is usually already established and the energy concessionaires opt for drastic pruning, which can compromise tree sanity and stimulate epicormic shoots, that grows quickly toward the aerial networks. Therefore, the present study had the objective of determining the growth rate of epicormic shoots after it having been pruned by CPFL for the species Tipuana tipu (Benth.) Kuntze; Tabebuia heptaphylla (Vell.) Mart.; and Terminalia catappa L. in the city of Piracicaba, São Paulo, Brazil, and relate this rate to the tree and environment characteristics. For that, a field survey was made of variables such as the species, diameter at breast height (DBH), leaf area index (LAI), type of pavement, type of soil, and photos of the treebed and shoots next to a beacon for later digital measurement, which had its reliability tested and approved in this study. The analysis was performed with all species together, for each species separately, and by dbh class within each species. The average daily growth rate for Tipuana tipu was 0.360 cm; for Tabebuia heptaphylla was 0.298 cm; and for Terminalia catappa was 0.404 cm. There was a significant difference between the growth rate of Terminalia catappa and Tabebuia heptaphylla, indicating that the species and its successional group influence the growth rhythm. There was no influence of the type of sidewalk or of the type of soil in the growth rate. The LAI also did not influence any growth, just for Tabebuia Heptaphylla with DBH between 50 and 60 cm. The treebed area did not influenced the Terminalia catappa shoots growth, but it had influenced positively the Tipuana tipu with 60 to 70 cm of DBH, wich were the trees with the greater growth rate of the species, as much as the Tabebuia heptaphylla with DBH between 30 and 40 cm, which are at a fairly vigorous age and their roots continue to explore the soil. There are a few studies with this theme and factors such as climate, pruning season and area management history can influence tree response to pruning. Therefore, longer study time with the same individuals and more trees included is suggested.

Thesis (LL. M.)--Judge Advocate General's School, U.S. Army, 1972. / "March 1972." Typescript. Includes bibliographical references (leaves 77-81). Also issued in microfiche.

The aim of the thesis was to evaluate the stand microclimate within fir-beech stand planted in the gap under the adult spruce stand canopy protection at the ecosystem station of Rájec (Drahanská vrchovina Highlands, the Czech Republic) during the growing season (May -- October) in 2014. On the fir-beech stand incident on average for the whole growing season only 11 % of photosynthetically active radiation incident on the adult spruce stand. Values of air temperature were decreasing in the vertical profile of fir-beech stand under the adult spruce stand canopy protection toward to the ground. Air temperature in the height of 2 meters above the ground was lower in the fir-beech stand in the gap compared with the adult spruce stands. The relative air humidity in the height of 2 meters above the ground was higher in the fir-beech stand compared with the adult spruce stands. Total precipitation sum was 447 mm at the ecosystem station of Rájec after the growing season (May -- October) in 2014, which corresponds to the long-term averages for this locality. Different distribution of rainfall during the growing season were found out. Total throughfall sum was higher in fir-beech stand in the gap compared with the throughfall sum in the adult spruce stand -- the difference was almost 17 %. Analysis of the stand microclimate within the fir-beech stand under the adult spruce stand canopy protection showed that conversion of forest monoculture on the forest close to the nature by the trees planting in forest gaps is useful due to appropriate light and moisture conditions in the gap.

This diploma thesis is focused on winter rape growth and development modeling by DSSAT software. The date of flowering, date of maturity, yields, above ground biomass dynamics and LAI dynamics were used for parameterization and consequent validation of the selected model. The data from field trials conducted by Central Institute for Supervising and Testing in Agriculture (ÚKZÚZ) within Lednice station (period from 1999 to 2006) and Domanínek station (period from 1999 to 2011) were used for simulations. Moreover data from field trials conducted by Mendel University in Brno within Domanínek station (period from 2012 to 2014) were used for winter rape modeling. This experiment consisted of eight variants with different sowing dates, nitrogen fertilization amounts and two cultivars. The dataset for DSSAT model testing was prepared based on above mentioned experiments. Despite the first attempt to simulate winter rape growth and development in Central Europe by DSSAT model, interesting results were achieved. Although some deviations between observed and simulated parameters appeared, the model was able to mimic characteristic crop growth dynamics. One of the main shortcomings is that model is not able to simulate necrosis of leaves within winter period. On the other hand, the model was able to reproduce the effect of different climatic conditions within included locations (i.e. later onset of observed phenophases within cooler station with higher elevation etc.) and the parameters were estimated with higher accuracy at Domanínek station.

A principal função da arborização viária, nos últimos 30 anos, passou de apenas estética para promotora de serviços ambientais, mas essas árvores estão submetidas a diversos fatores estressantes, como a poluição do ar, a baixa disponibilidade de água, solo compactado, podas severas, e área de crescimento limitada. As redes aéreas de distribuição de energia são um dos elementos que mais interferem no manejo das árvores viárias, pois o conflito, geralmente, já está estabelecido e as concessionárias de energia optam por podas drásticas, que podem comprometer a sanidade da árvore e estimular brotações epicórmicas que crescem rapidamente e vão de encontro com as fiações. Posto isso, o presente estudo teve como objetivo determinar a taxa de crescimento de brotações epicórmicas após poda executada pela Companhia Paulista de Força e Luz (CPFL) em indivíduos das espécies tipuana (Tipuana tipu (Benth.) Kuntze), ipê-roxo (Tabebuia heptaphylla (Vell.) Mart.), e chapéu-de-sol (Terminalia catappa L.), na cidade de Piracicaba/SP e relacionar esta taxa com as características da árvore e do meio. Para isso, foi realizado levantamento em campo de variáveis como a espécie, diâmetro à altura do peito (DAP), índice de área foliar (IAF), tipo de calçada, tipo de solo, fotos do canteiro e dos brotos ao lado de uma baliza para posterior medição digital, que teve sua confiabilidade testada e aprovada nesta pesquisa. A análise foi executada com todas as espécies juntas, para cada espécie, e por classe de DAP dentro de cada espécie. O índice de crescimento médio diário para a tipuana foi de 0,360 cm; para o ipê-roxo, 0,298 cm; e para chapéu-de-sol, 0,404 cm. Houve diferença significativa entre a taxa de crescimento da espécie chapéu-de-sol e ipê-roxo, indicando que a espécie e o grupo sucessional a qual pertencem influenciam no ritmo de crescimento. Não foi constatada influência do tipo de calçada e nem do tipo de solo. O IAF também não influenciou no crescimento, a não ser em ipês com DAP entre 50 e 60 cm. A dimensão do canteiro não influenciou o crescimento dos brotos de chapéu-de-sol, mas influenciou positivamente tanto as tipuanas com 60 a 70 cm de DAP, que foram as árvores com o maior ritmo de crescimento da espécie, como os ipês com DAP entre 30 e 40 cm que ainda estão vigorosos e suas raízes continuam explorando o solo. Os estudos com essa temática são poucos e fatores como clima, época de poda e histórico de manejo da área podem exercer influência na resposta da árvore à poda. Portanto, é sugerido maior tempo de estudo com os mesmos indivíduos e a inclusão de mais árvores. / The main function of the street trees, in the last 30 years, had been switched from aesthetic to the promotion of environmental services. However, this trees are submitted to a lot of stressful factors like limited growth aerea, air pollution, low water availability, compacted soil and drastic pruning. Aerial power networks distribution are the elements that most interfere with the management of street trees, because the conflict is usually already established and the energy concessionaires opt for drastic pruning, which can compromise tree sanity and stimulate epicormic shoots, that grows quickly toward the aerial networks. Therefore, the present study had the objective of determining the growth rate of epicormic shoots after it having been pruned by CPFL for the species Tipuana tipu (Benth.) Kuntze; Tabebuia heptaphylla (Vell.) Mart.; and Terminalia catappa L. in the city of Piracicaba, São Paulo, Brazil, and relate this rate to the tree and environment characteristics. For that, a field survey was made of variables such as the species, diameter at breast height (DBH), leaf area index (LAI), type of pavement, type of soil, and photos of the treebed and shoots next to a beacon for later digital measurement, which had its reliability tested and approved in this study. The analysis was performed with all species together, for each species separately, and by dbh class within each species. The average daily growth rate for Tipuana tipu was 0.360 cm; for Tabebuia heptaphylla was 0.298 cm; and for Terminalia catappa was 0.404 cm. There was a significant difference between the growth rate of Terminalia catappa and Tabebuia heptaphylla, indicating that the species and its successional group influence the growth rhythm. There was no influence of the type of sidewalk or of the type of soil in the growth rate. The LAI also did not influence any growth, just for Tabebuia Heptaphylla with DBH between 50 and 60 cm. The treebed area did not influenced the Terminalia catappa shoots growth, but it had influenced positively the Tipuana tipu with 60 to 70 cm of DBH, wich were the trees with the greater growth rate of the species, as much as the Tabebuia heptaphylla with DBH between 30 and 40 cm, which are at a fairly vigorous age and their roots continue to explore the soil. There are a few studies with this theme and factors such as climate, pruning season and area management history can influence tree response to pruning. Therefore, longer study time with the same individuals and more trees included is suggested.

This thesis uses the referent “My Lai Massacre” to refer to the mythic memory of what happened in Son My on 16 March, 1968. It argues that it is a fitting name for the way it captures the ethnocentrism of the memory in the name by perpetuating an American misnomer rooted in ignorance. It also singularizes the scope of horrors of the day, and fails to differentiate ‘the massacre’ from the domestic turmoil with which it was conflated. The My Lai Massacre narrative as it currently exists in American history and memory is ‘exceptionalist’ in that it incorporates and excludes story elements in such a way that casts it as a highly exceptional occurrence. The main argument of this thesis is that American history and memory of the ‘My Lai Massacre’ have, to a large degree, been defined and shaped by conservative influences. In the time since the news of the atrocities became public this has manifested itself in a number of way and is not confined to conservative histories of the war. Despite the hold liberal orthodox scholarship has on the history of the war, there remains within it, this thesis argues, a conservative trend regarding the massacres in Son My. Reactions, explanations, and rationalizations that appeared in early conservative responses to news of the massacres have survived into a wider ideological spectrum of Vietnam scholarship and memory than that from which it came. Although it seems at first consideration an unlikely event from which a usable past might be constructed, the My Lai Massacre does get used in a didactic manner. This thesis examines some of the most prevalent ways the memory of My Lai functions as a usable past. The My Lai Massacre has been incorporated into a number of ‘lessons of the past’ that tend to be derived from conservative narratives of the war.