Nitrogen dioxide (NO2) levels were measured inside and adjacent to canopies of urban trees in Springfield, MA, over two growing seasons. Nitrogen dioxide levels were consistently and significantly higher inside tree canopies compared to levels outside. During the second growing season, ozone (O3), temperature, and relative humidity (RH) were also measured using samplers co-located with the NO2 samplers. Ozone levels were significantly lower inside the canopy whereas temperatures were higher inside the canopy, and RH was not different between inner and outer canopy locations. The results corroborate theoretical models predicting elevated NO2 and depressed O3 levels inside tree canopies based on photochemistry, but put into question the mechanisms involved in generating these levels. In a separate study, the use of a common urban street tree (Acer rubrum) as a tool for measuring NO2 uptake under field conditions was evaluated using a model previously applied only to potted herbaceous plants and coniferous trees. Using potted saplings of A. rubrum located at locations with high or low NO2 levels in Springfield, MA, and Amherst, MA, we measured 15N stable isotope signatures (δ15N) and total N (%N) of leaves throughout the growing season. There was no significant difference in leaf δ15N or %N change between sites over the course of the season. Changes in δ15N were likely the result of input from N sources in the nutrient solution. Changes in %N followed a natural seasonal decline reported elsewhere in the literature. The study highlights the difficulties in applying this particular model to deciduous trees and suggests work needed to overcome these challenges.

A disponibilidade de dados quantitativos confiáveis é primordial para compreensão da Ecologia de áreas verdes, pois a partir deles é possível entender o funcionamento desses ecossistemas e avaliar sua participação no fornecimento de serviços ambientais. As áreas verdes podem ser compreendidas como uma rede dentro da matriz urbana composta por fragmentos, representados por parques, praças e áreas de proteção, interligados por corredores, principalmente matas ciliares e ruas arborizadas. Em diversos estudos, a caracterização das áreas verdes se baseia na distribuição da cobertura arbórea e do uso do solo mensurados por processos que utilizam técnicas de interpretação de imagens de sensoriamento remoto e de geoprocessamento, que têm se tornado mais acessíveis com os softwares livres. A cobertura arbórea inclui populações de árvores de rua e populações de árvores que não são de rua, que constituem aglomerados. No capítulo 2, são aplicados sobre 6 bairros de Rio Claro - SP (Brasil) 6 processos de mapeamento do solo: Dot grid; Classificação Automática Supervisionada; Classificação Automática Supervisionada com uso do NDVI; Classificação Automática Não Supervisionada; Classificação Automática Não Supervisionada com uso do NDVI; Vetorização, aplicada apenas à cobertura arbórea. Os processos foram equivalentes na quantificação dos diversos tipos de cobertura (Estatísticas Kappa >= 0,75) e forneceram dados acurados de quantificação da cobertura arbórea (teste de Tukey, com dados de referência da Vetorização), exceto para Classificação Automática Supervisionada. Obteve-se melhor desempenho das classificações automáticas com o NDVI combinado à imagem multiespectral. Avaliações mais refinadas das áreas verdes acessam informações sobre a comunidade vegetal que as compõe por levantamentos em campo. O tipo de inventário florestal a ser utilizado depende dos objetivos e é limitado pelo tempo e recursos financeiros disponíveis. No que tange as árvores de rua, processos de amostragem podem fornecer informações adequadas para muitos projetos, além de reduzirem custos, pois a amostra da população é suficiente para visão geral de todos os aspectos, embora se percam informações específicas dos indivíduos. No capítulo 3, investiga-se a eficiência do inventário florestal pelos métodos de amostragem sistemática simples e amostragem sistemática estratificada da população de árvores de rua da área densamente urbanizada de Piracicaba - SP (Brasil), tendo como variável de estratificação a porcentagem de cobertura de árvores de rua e como variáveis de interesse: densidade em número de indivíduos por quilômetro de calçada (Df), densidade em área basal por quilômetro de calçada (Dg), altura total média (Ht), densidade em volume por quilômetro de calçada (Dv), densidade em número de espécies por quilômetro de calçada (De). Avaliou-se também o uso de diferentes unidades amostrais representadas por: 1, 2, 3 e 4 quarteirões. Para tanto, foram amostrados sistematicamente 90 conjuntos de 4 quarteirões, nos quais foram levantados os indivíduos com CAP >= 12 cm plantados em calçada e canteiro central. Pela redução no Esforço amostral, foi possível observar que a amostragem sistemática estratificada foi mais eficiente que a amostragem sistemática simples, especialmente para Df, Dg e Dv. O aumento no tamanho da unidade amostral também provocou redução no Esforço amostral, porém houve aumento na Intensidade de amostragem. / The availability of reliable quantitative data is primordial to understanding the Ecology of green spaces, because from them it is possible to know the functioning of these ecosystems and to evaluate their participation in provision of ecosystems services. Green spaces can be understood as a network within the urban matrix composed of fragments, represented by parks, squares and protected areas, interconnected by corridors, especially riparian forests and wooded streets. In several studies, the characterization of green areas has been based on the distribution of tree cover and land use processes measured by using techniques of interpretation of remote sensing images and GIS, which have become more accessible with the development of software free. The tree cover includes populations of street trees and populations of no street tree, forming aggregation. In chapter 2, 6 mapping processes of urban land are applied over 6 districts of Rio Claro city - SP (Brazil): Dot grid; Supervised Automatic Classification; Supervised Automatic Classification using NDVI; Unsupervised Automatic Classification; Unsupervised Automatic Classification using NDVI; Vector, applied only to tree cover. The processes were equivalent in the quantification of the several types of coverage (Kappa Statistic greater than 0.75) and provided accurate quantification data of tree cover (Tukey Test, with quantification by Vector as reference data), except for Supervised Automatic Classification. Best performance of automatic classifications was obtained by NDVI combination with multispectral imaging. More refined assessments of green spaces access information on vegetal community that makes up the tree cover through field surveys. The type of forest inventory to be used depends on the established goals and is limited by time and financial resources. In terms of street trees, the sampling methods can provide adequate information for many projects as well as reducing costs, since the sample is sufficient to overview of all aspects, despite losing specific information of each individual. In Chapter 3, we investigate the efficiency of forest inventory methods by simple systematic sampling and stratified systematic sampling of the street tree population in densely urbanized area of Piracicaba - SP (Brazil), with the percentage of street tree cover as stratification variable and the interest variables are: number of individuals per kilometer of sidewalk (Df), basal area per kilometer of sidewalk (Dg), total height mean (Ht), volume per kilometer of sidewalk (Dv) , number of species per kilometer of sidewalk (De). The use of different sampling units was evaluated too: 1 block, 2 blocks, 3 blocks, and 4 blocks. For that, 90 sets of 4 blocks were systematically sampled, in which individuals with CAP >= 12 cm planted in sidewalk and median were raised. By the reduction in Sample size (Ne), it was observed that the systematic stratified sampling was more efficient than simple systematic sampling, especially for Df, Dg and Dv. The increase in the size of the sampling units also caused reduction in Sample size, but there was an increase in the Sample intensity (I%).

A disponibilidade de dados quantitativos confiáveis é primordial para compreensão da Ecologia de áreas verdes, pois a partir deles é possível entender o funcionamento desses ecossistemas e avaliar sua participação no fornecimento de serviços ambientais. As áreas verdes podem ser compreendidas como uma rede dentro da matriz urbana composta por fragmentos, representados por parques, praças e áreas de proteção, interligados por corredores, principalmente matas ciliares e ruas arborizadas. Em diversos estudos, a caracterização das áreas verdes se baseia na distribuição da cobertura arbórea e do uso do solo mensurados por processos que utilizam técnicas de interpretação de imagens de sensoriamento remoto e de geoprocessamento, que têm se tornado mais acessíveis com os softwares livres. A cobertura arbórea inclui populações de árvores de rua e populações de árvores que não são de rua, que constituem aglomerados. No capítulo 2, são aplicados sobre 6 bairros de Rio Claro - SP (Brasil) 6 processos de mapeamento do solo: Dot grid; Classificação Automática Supervisionada; Classificação Automática Supervisionada com uso do NDVI; Classificação Automática Não Supervisionada; Classificação Automática Não Supervisionada com uso do NDVI; Vetorização, aplicada apenas à cobertura arbórea. Os processos foram equivalentes na quantificação dos diversos tipos de cobertura (Estatísticas Kappa >= 0,75) e forneceram dados acurados de quantificação da cobertura arbórea (teste de Tukey, com dados de referência da Vetorização), exceto para Classificação Automática Supervisionada. Obteve-se melhor desempenho das classificações automáticas com o NDVI combinado à imagem multiespectral. Avaliações mais refinadas das áreas verdes acessam informações sobre a comunidade vegetal que as compõe por levantamentos em campo. O tipo de inventário florestal a ser utilizado depende dos objetivos e é limitado pelo tempo e recursos financeiros disponíveis. No que tange as árvores de rua, processos de amostragem podem fornecer informações adequadas para muitos projetos, além de reduzirem custos, pois a amostra da população é suficiente para visão geral de todos os aspectos, embora se percam informações específicas dos indivíduos. No capítulo 3, investiga-se a eficiência do inventário florestal pelos métodos de amostragem sistemática simples e amostragem sistemática estratificada da população de árvores de rua da área densamente urbanizada de Piracicaba - SP (Brasil), tendo como variável de estratificação a porcentagem de cobertura de árvores de rua e como variáveis de interesse: densidade em número de indivíduos por quilômetro de calçada (Df), densidade em área basal por quilômetro de calçada (Dg), altura total média (Ht), densidade em volume por quilômetro de calçada (Dv), densidade em número de espécies por quilômetro de calçada (De). Avaliou-se também o uso de diferentes unidades amostrais representadas por: 1, 2, 3 e 4 quarteirões. Para tanto, foram amostrados sistematicamente 90 conjuntos de 4 quarteirões, nos quais foram levantados os indivíduos com CAP >= 12 cm plantados em calçada e canteiro central. Pela redução no Esforço amostral, foi possível observar que a amostragem sistemática estratificada foi mais eficiente que a amostragem sistemática simples, especialmente para Df, Dg e Dv. O aumento no tamanho da unidade amostral também provocou redução no Esforço amostral, porém houve aumento na Intensidade de amostragem. / The availability of reliable quantitative data is primordial to understanding the Ecology of green spaces, because from them it is possible to know the functioning of these ecosystems and to evaluate their participation in provision of ecosystems services. Green spaces can be understood as a network within the urban matrix composed of fragments, represented by parks, squares and protected areas, interconnected by corridors, especially riparian forests and wooded streets. In several studies, the characterization of green areas has been based on the distribution of tree cover and land use processes measured by using techniques of interpretation of remote sensing images and GIS, which have become more accessible with the development of software free. The tree cover includes populations of street trees and populations of no street tree, forming aggregation. In chapter 2, 6 mapping processes of urban land are applied over 6 districts of Rio Claro city - SP (Brazil): Dot grid; Supervised Automatic Classification; Supervised Automatic Classification using NDVI; Unsupervised Automatic Classification; Unsupervised Automatic Classification using NDVI; Vector, applied only to tree cover. The processes were equivalent in the quantification of the several types of coverage (Kappa Statistic greater than 0.75) and provided accurate quantification data of tree cover (Tukey Test, with quantification by Vector as reference data), except for Supervised Automatic Classification. Best performance of automatic classifications was obtained by NDVI combination with multispectral imaging. More refined assessments of green spaces access information on vegetal community that makes up the tree cover through field surveys. The type of forest inventory to be used depends on the established goals and is limited by time and financial resources. In terms of street trees, the sampling methods can provide adequate information for many projects as well as reducing costs, since the sample is sufficient to overview of all aspects, despite losing specific information of each individual. In Chapter 3, we investigate the efficiency of forest inventory methods by simple systematic sampling and stratified systematic sampling of the street tree population in densely urbanized area of Piracicaba - SP (Brazil), with the percentage of street tree cover as stratification variable and the interest variables are: number of individuals per kilometer of sidewalk (Df), basal area per kilometer of sidewalk (Dg), total height mean (Ht), volume per kilometer of sidewalk (Dv) , number of species per kilometer of sidewalk (De). The use of different sampling units was evaluated too: 1 block, 2 blocks, 3 blocks, and 4 blocks. For that, 90 sets of 4 blocks were systematically sampled, in which individuals with CAP >= 12 cm planted in sidewalk and median were raised. By the reduction in Sample size (Ne), it was observed that the systematic stratified sampling was more efficient than simple systematic sampling, especially for Df, Dg and Dv. The increase in the size of the sampling units also caused reduction in Sample size, but there was an increase in the Sample intensity (I%).

La végétation influence le climat urbain de l'échelle de la rue à l'échelle de la ville. Les arbres de rue, en particulier, constituent une technique alternative à l'atténuation de l'îlot de chaleur urbain et à l'amélioration du confort thermique. Ils modifient les bilans radiatif et énergétique en interceptant et absorbant une partie du rayonnement solaire incident, créent de l'ombre, augmentent l'humidité relative de l'air par évapotranspiration et modifient également les écoulements d'air dans le canyon urbain. Le modèle TEB est un des rares modèles de climat urbain prenant en compte la végétation. Il intègre des paramétrisations dédiées à la végétation basse dans les canyons urbains et aux toitures végétalisées, et peut représenter les interactions de petite échelle entre les surfaces minéralisées, la végétation et l'atmosphère. Dans le cadre de cette thèse, une paramétrisation a été implémentée dans TEB pour modéliser les aspects radiatifs, énergétiques et aérauliques liés à la présence d'arbres de rue dans l'espace urbain. Une canopée arborée explicite a été intégrée dans le canyon urbain au-dessus de la chaussée et des jardins. Le modèle ISBA est utilisé pour représenter les strates haute et basse de la végétation. Les calculs radiatifs du modèle TEB ont été modifiés afin de prendre en compte les effets d'ombrage et d'atténuation du rayonnement solaire et IR liés à la présence de cette canopée, et les interactions IR entre l'ensemble des éléments urbains du canyon. Une évaluation du bilan radiatif a été réalisée grâce à une comparaison avec le modèle architectural d'ensoleillement à haute résolution SOLENE, sur la base de simulations de canyons urbains idéalisés et pour différentes configurations d'arbres de rue. Les flux d'énergie calculés par ISBA selon l'approche \textit{big leaf} ont ensuite été désagrégés entre les contributions de la végétation haute et basse. Les flux des arbres ont été redistribués sur la verticale de façon à modifier le microclimat à hauteur réaliste vis-à-vis de la position de la canopée arborée. Un effet de traînée lié à la présence de la canopée arborée a été intégré dans les équations de quantité de mouvement et d'énergie cinétique turbulente résolues par la paramétrisation de couche limite de surface de TEB pour le volume d'air au sein du canyon. Une évaluation en cas réel de cette nouvelle version du modèle a été conduite sur un site expérimental, à savoir une cour semi-fermée aménagée avec des arbres et où ont été collectées différentes variables microclimatiques. Les résultats montrent des améliorations considérables quant à la modélisation des températures de surface des murs et du sol, de la température de l'air sous la canopée arborée, et de la vitesse du vent. Ces implémentations visent à simuler de façon plus réaliste différentes stratégies d'adaptation par la végétalisation et d'évaluer leurs performances sur l'atténuation de l'îlot de chaleur urbain, le confort thermique, et la consommation d'énergie des bâtiments. / Vegetation influences the urban climate, from road to city scale. Street trees implementation is an alternative technic to reduce the urban heat island and to improve the thermal comfort. They modify the radiative and energetic balances by intercepting and absorbing a part of the solar radiation, provide shade, increase the humidity with evapotranspiration, and alter the air flow in the urban canyons. The TEB model is one the rare urban climate models taking into account vegetation. It integrates parameterizations dedicated to low vegetation and green roofs. It can represent the small-scale interactions between mineral surfaces, vegetation and the atmosphere. During this PhD thesis, a parameterization has been developed to model the radiative, energetic and dynamical effects of street and garden trees in urban spaces. An explicit tree canopy has been integrated into the urban canyon, above gardens but also streets. The ISBA vegetation scheme has been used, and included in TEB, to represent these vegetated entities (both low and high strata). The radiative computations of the TEB model have been improved in order to represent the shading and attenuation of radiation due to trees, as well as all the infra-red interactions between the urban elements. An evaluation of the radiative budget has been done thanks to a comparison with the high- resolution architectural model SOLENE, using numerous different urban canyons with several layouts of tree canopies. Then, the energy fluxes computed by ISBA have been dis- aggregated between contributions from high and low vegetation. Fluxes allocated to the trees have been redistributed on the vertical in order to alter the microclimate at realistic height, i.e. respecting the position of the tree crown. A specific drag force of trees on the airflow is simulated. An evaluation has been done on a real experimental site in a canyon-like courtyard with trees where several microclimatic data were collected. The results show an impressive improvement of the surface temperatures of walls and ground, air temperature and wind speed. In the future, these implementations will allow to simulate more realistically several adaptation strategies using greening at city scale, and to evaluate their efficiency in terms of urban heat island mitigation, improvement of human comfort and building energy consumption.

Developing quantified establishment period estimates for newly planted trees will help set realistic goals for plant performance in the urban landscape. Nine years of tree planting records obtained from the city of Boston, MA and the town of Brookline, MA were used to derive samples of trunk caliper for hedge maple (Acer campestre), London planetree (Platanus x acerifolia), and red oak (Quercus rubra). Several site characteristics were measured to identify effects on newly planted tree growth. Breakpoint estimates of the piecewise regression models fell at 4 years and 6 years for London planetree and hedge maple respectively, showing establishment periods for urban trees are longer than the conventional 3 years. Pit area has a significant effect on caliper growth for London planetree and red oak, with larger growing spaces yielding larger trees. Observed soil bulk densities did not have a significant effect on caliper measurement for any of the species tested. Mean soil bulk density was 1.4 g/cm3, 1.45 g/cm3, and 1.49 g/cm3 for hedge maple, London planetree, and red oak respectively. Soil texture was significant for hedge maple only, with percent clay showing significant positive effects and percent sand as marginally significant. Pit type showed a significant effect on caliper measurement of London planetree with grass strips producing the largest caliper trees followed by open pits. Planting locations with tree grates produced the smallest caliper trees. Presence of perforated air vents produced significantly larger caliper trees than sites with an air vent present for red oak.

Urban runoff continues to impair water quality and there is an increasing need for stormwater management within the limited confines of urban spaces. We propose a system of structural soil and trees that can be incorporated beneath pavement. Structural soil has a high load-bearing capacity yet is engineered to support tree root growth. Stormwater is directed into a structural soil reservoir below the pavement where tree roots can also thrive. Two container experiments evaluated tree function in this system. We examined whether tree roots can grow into compacted subsoils and if root penetration increases soil infiltration rate. Quercus velutina, Acer rubrum, and a no-tree variant were planted in 26.5 L (7 gal) containers and the rootballs surrounded by compacted clay loam. Roots grew into all layers of the compacted soil. Infiltration rate increased by 63% (+/-2%) compared to no-tree containers. A second experiment evaluated water uptake and tree development in fluctuating water tables. Quercus bicolor and Fraxinus pennsylvanica were planted in 94.6 L (25 gal) containers with structural soils (either Stalite or CU® Structural Soil). Trees were subjected to fluctuating water tables simulating infiltration rates of 2, 1, and 0.1 cm/hr for two growing seasons. Trees thrived in all infiltration regimes but roots were shallower in slowly drained treatments. Trees grew best and transpired the highest water volume with moderate infiltration. Even if trees uptake only small volumes of water, increased canopy size compared to conventional plantings (because of greater penetrable soil volume) allows greater rainfall interception thus decreasing runoff. / Master of Science