• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 62
  • 27
  • 5
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 134
  • 134
  • 34
  • 31
  • 31
  • 26
  • 26
  • 26
  • 22
  • 22
  • 20
  • 18
  • 16
  • 15
  • 12
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Valuation of Tree Canopy on Property Values of Six Communities in Cincinnati, Ohio

Dimke, Kelley C. 24 June 2008 (has links)
No description available.
72

Investigating the Impact of Urban Tree Planting Strategies for Shade and Residential Energy Conservation

Hwang, Won Hoi 04 September 2015 (has links)
Expanding urbanization, characterized by increased impervious surfaces and decreased tree canopy, is contributing to rising urban temperatures. This trend has implications for energy consumption, which strategically placed trees can modify by casting shade upon building and ground surfaces. However, urban densification, a paradigm of modern residential land development, often constrains space for planting shade trees. Thus, the overall objective of this dissertation was to investigate shade tree planting strategies and their effects on residential cooling and heating energy conservation for dense urban neighborhoods in U.S. cities on a latitudinal gradient. The first study used a computer program called Shadow Pattern Simulator to examine the effects of tree form, tree placement, and sunlight exposure on shade provision for a residential structure model. Simulation results affirmed the conventional strategy in northern latitudes that recommends planting shade trees on the east or west aspect for maximizing beneficial shade while avoiding tree plantings on the south aspect to minimize any heating penalty of undesirable shade. However, in southern latitudes, planting trees on southerly aspect should not be discounted because the shorter heating season lessens the detrimental heating penalty while providing beneficial season shade. The second study, using an energy simulation program called EnergyPlus, evaluated the effect of a single shade tree upon the energy consumption of the structure model. This study affirmed that energy conservation benefits are influenced by the quantity as well as the quality of tree shade upon building surfaces. In addition, interactions between sun angle, tree form, and tree placement were observed to influence tree shade effects on annual energy consumption. In the third study, based on the first two studies, an alternative tree placement strategy, which reconfigured tree placement around the residential structure, was developed to maximize cooling and heating energy savings while attenuating space conflicts. The alternative strategy was found to be as effective as the conventional strategy while being more responsive to parcel or building orientations in dense urban neighborhoods. Overall, understanding the fundamental interactions between tree form, tree placement, and geographic settings is critical for improving energy conservation benefits of shade trees in dense urban settings. / Ph. D.
73

Street Trees as a Source of Timber in Washington, DC

Grieve, Alexander Joseph 24 January 2017 (has links)
Recycling felled urban trees that are hazardous or unhealthy is increasingly viewed as a viable practice to control disposal costs, promote environmental practices, and support local commerce. Wide spread waste wood utilization is encumbered by numerous presumptions about wood quantity, quality, accessibility, and presence of foreign objects; yet there is almost no scientific literature about these presumptions. Without this knowledge, informed decisions cannot be made about the viability of waste wood utilization. In this study, we assessed the quality and quantity of timber in street trees scheduled for routine removal by the District of Columbia (the District) using a modified timber grading protocol adapted from the United States Forest Service. We developed a second protocol to assess the feasibility of timber salvage by identifying physical barriers commonly encountered in urban areas (e.g., high volume traffic, utilities around the tree, and infrastructure). The randomized sampling scheme was stratified by land-use zones and focused on the six most abundant tree species: Acer platanoides, Acer rubrum, Acer saccharum, Quercus palustris, Quercus phellos, Quercus rubra. Our findings suggest the majority of condemned street trees are of too poor quality to contain timber (58% cull rate); however, trees that contain merchantable logs are likely to be easily removed. A notable discovery that could prove problematic for wood salvage was that the majority of trees (88%) contained superficial metal items embedded in the trunk surface. Furthermore, presence or absence of a merchantable-sized log (p=0.0445) depended on the tree's species, as did the average volume observed (p<0.0001). Additionally, land-use zones had an effect on the removal feasibility scores (p=0.0257) but had no effect on log presence or log volume. Throughout the District, we estimated that 36,500 board feet of merchantable logs are generated from routine removals of our top six species annually. These findings provide empirical data pertaining to urban timber salvage, which might aid decisions on the investment worthiness of utilizing urban street trees. / Master of Science
74

Growth and Physiology of Several Urban Tree Species in Soils Disturbed by Construction Fill or Compaction

Day, Susan D. 24 August 1999 (has links)
Experiments were conducted to determine the effects of applying fill soil around existing trees and mechanisms for species tolerance to soil compaction, both common site disturbances in urban forestry. Groups of 22-year-old white oak (Quercus alba) and 13-year-old sweetgum (Liquidambar styraciflua) were subjected to one of three treatments: a control, fill (20 cm of subsoil spread over the root zones), and compacted fill (same as fill soil, but compacted). Additionally, individual trees had tree wells (fill soil pulled away from trunks), or not. After three years, treatments had no consistent effect on tree growth, chlorophyll fluorescence, or soil respiration. However, soil treatments disrupted normal soil moisture patterns at both sites. Roots of white oak grew into fill layers, although overall root growth was not significantly affected by treatment. Sweetgum roots grew very little into fill soils. However, root distribution shifted upward in the original soil under uncompacted fill. Other factors associated with raising the soil grade, such as soil trafficking and root severance, may be largely responsible for the tree decline often attributed to construction fill. Another experiment investigated the relationship between tolerance of wet soils and the ability to grow in compacted soils. It was hypothesized that tree species tolerant of wet soils would have opportunities for root growth in compacted soil when high soil moisture reduced soil strength. Seedlings of flowering dogwood (Cornus florida), a species intolerant of inundation, and silver maple (Acer saccharinum), a bottomland species, were grown in a loam soil maintained at various combinations of soil strength and soil matric potential. In moderately compacted soil (1.5 g cm-3 bulk density), maple seedlings, but not dogwoods, had greater root growth rate, root length per plant, and ratio of root length to root dry weight in the wet soil (0.006 MPa soil matric potential) than in the moist and dry soils (0.026 and 0.06 MPa, respectively). No such effect was detected in highly compacted soil (1.7 g cm-3). It can be concluded that silver maple roots can grow in moderately compacted soil when high soil water content decreases soil strength, whereas dogwood is unable to take advantage of this opportunity. / Ph. D.
75

Vilse i skogen : Urban Forestry som möjlighet eller problem? / Urban Forestry as an opportunity or problem?

Bensköld, Manda, Jacobsson, Christine January 2019 (has links)
Detta kandidatarbete syftar till att utreda om Urban Forestry kan tillföra något till svensk planering. Urbanisering har skett under en lång tid och för att tillgodose det växande behovet av bostäder har förtätning av staden skett, vilket ofta har gjorts på bekostnad av städers grönska. För att hantera utmaningarna med att integrera grönska i täta städer har ett behov av nytänkande grönplanering uppkommit. Urban Forestry anses vara en lösning på denna problematik och fokuserar på att skapa gröna städer där det inte finns ytor kvar för traditionella parker. För att undersöka om Urban Forestry tillför något nytt till svensk planering utreds grönplaneringens utveckling genom tiderna samt företeelsen Urban Forestry genom en litteraturstudie. Urban Forestry visade sig vara ett vagt och svårdefinierat begrepp, dessutom är de vetenskapliga grunderna för dess positiva miljöeffekter bristande. Dock bidrar Urban Forestry med uppmärksammande av miljö- och hållbarhetsfrågor, och visar goda ambitioner och initiativ till att utveckla och förbättra grönplanering. När den svenska grönplaneringen sattes i relation till Urban Forestry visade det sig att de bärande idéerna redan är representerade inom existerande grönplanering i Sverige. / This bachelor thesis aims to investigate if the concept of Urban Forestry could bring new knowledge into Swedish urban planning. Urbanization has taken place for a long time and in order to meet the growing need for housing, densification of the city has taken place, which has often been done at the expense of urban greenery. In order to deal with the challenges of integrating greenery into dense cities, a need for innovative green planning has arisen. Urban Forestry as a concept is considered a solution to this problem and focuses on creating greenery in cities where limited areas for traditional parks are available. In order to investigate whether Urban Forestry adds something new to Swedish planning, the development of green planning over time and the concept of Urban Forestry is investigated. Urban Forestry turned out to be vague and difficult to define, and the scientific basis for the concept’s arguments are lacking. However, Urban Forestry contributes attention to environmental and sustainability issues, and shows good ambitions and initiatives to develop and improve green planning. When Swedish green planning was put in relation to Urban Forestry, the outcome was that the ideas in the concept were already represented within existing green planning.
76

Urban Trees as Sinks for Soot: Deposition of Atmospheric Elemental Carbon to Oak Canopies and Litterfall Flux to Soil

Rindy, Jenna 05 1900 (has links)
Elemental carbon (EC), a product of incomplete combustion of fossil fuels and biomass, contributes to climate warming and poor air quality. In urban areas, diesel fuel trucks are the main source of EC emissions from mobile sources. After emission, EC is deposited to receptor surfaces via two main pathways: precipitation (wet deposition) and directly as particles (dry deposition). Urban trees may play an important role in removing EC from the atmosphere by intercepting and delivering it directly to the soil. The goal of this research was to quantify the magnitude of EC retention in leaf waxes (in-wax EC) and EC fluxes to the soil via leaf litterfall in the City of Denton, Texas. Denton is a rapidly growing urban location in the Dallas-Fort Worth metropolitan area. A foliar extraction technique was used to determine EC retention in leaf waxes. Foliar samples were collected monthly, from April through July, from pairs of Quercus stellata (post oak, n=10) and Quercus virginiana (live oak, n = 10) trees. Samples were rinsed with water and chloroform in a two-step process to determine EC retained in leaf waxes. A Sunset OC/EC aerosol analyzer was utilized to analyze the EC content of extracts filtered onto quartz-fiber filters. From April through July, leaf litter was collected bi-weekly under 35 trees (20 post oak, 15 live oak), and oven dried to determine dry weight. EC retained by tree canopies was estimated by multiplying in-wax EC by canopy leaf area index, while EC flux to soil was estimated by multiplying in-wax EC by leaf litterfall mass. This study shows that through retention of EC in leaf waxes, urban tree canopies represent important short-term sinks for soot in urban areas.
77

Loss of Urban Forest Canopy and the Related Effects on Soundscape and Human Directed Attention

Laverne, Robert James January 2016 (has links)
No description available.
78

A arborização na qualificação do espaço da rua: uma proposta metodológica de inventário, manejo e planejamento de verde viário em dois bairros paulistanos / Urban streets florestation: a methodological approach for assessment, planning and handling of streetside green areas applied to two neighborhoods in São Paulo

Rossetti, Adriana Ines Napias 29 February 2008 (has links)
Foi realizado levantamento quanti-qualitativo de vegetais de porte arbóreo em dois bairros paulistanos, Vila Vera e Jardim da Saúde, situados na região sudeste de São Paulo, não distando muito entre si, porém com características de ocupação de uso de solo bastante distintas. No Jardim da Saúde foram encontrados 1033 exemplares de 72 espécies botânicas, a altura média de todas as árvores foi de 8,07 m e a altura da primeira bifurcação 1,97 m, a Caesalpinea peltophoroides Benth. foi a espécie mais freqüente com 20,68%, seguida da Lagestroemia indica L. com 7,48% e da Ligustrum lucidum W.T. Aiton em terceiro com 6,89%, essas três espécies somaram 35,05% dos indivíduos. Existiam 80,45% dos exemplares situados defronte a imóveis que possuíam recuo mínimo de 2,50 m de construções, 72,80% do total estavam em passeios que têm entre 1,00 m e 2,00 m, predominam árvores com mais de 8,50 m de altura, o pior indicador de sanidade vegetal seria a infestação de cupins com 8,33% do total infestado, 13,65% teve anotações de má qualidade de copa, 20,62% apresentou algum indicativo de má qualidade de tronco. Apenas 23,33% tinham situações de permeabilidade do passeio suficiente, encontravam-se 5,71% com condução de poda para desobstrução das redes aéreas, o rebaixamento das árvores acontecia em 7,74% dos exemplares. Na Vila Vera havia limitações de espaço físico não apenas das larguras dos passeios, mas principalmente do uso predominante dos lotes. As residências normalmente tomam todo o espaço da testada do imóvel com rebaixamento de guias para permitir a entrada veículos na garagem localizada defronte a construção. Encontraram-se 178 árvores pertencentes a 42 espécies botânicas, a média da altura total é de 6,31 m, e a média da primeira bifurcação 1,81 m. A espécie mais abundante foi a Caesalpinea peltophoroides Benth.com 24,71%, a segunda seria a Ligustrum lucidum W.T. Aiton com 17,24% do total, vindo em terceiro Lagerstroemia indica L. com 8,62%. Neste bairro existiam 71,35% das situações afastamento predial superior a 2,50 m, 42,70% com altura inferior a 4,50 m de altura, a sanidade vegetal estaria comprometida em 12,37% dos exemplares pela infestação de cupins, 55,62% estva localizada em passeios que variam sua largura entre 1,00 e 2,00 m, 50,00% apresentavam maus indicadores de qualidade de copa, 25,44% apresentou algum indicativo de má qualidade de tronco. Somente 7,87% do total de árvores estavam em situações de permeabilidade do passeio suficiente, os exemplares pavimentados até o tronco totalizavam 16,85%, as conduções de poda para desobstrução de redes eram 3,38% e as podas de rebaixamento 13,48%. Havia uma média de 16,85 m de afastamento entre árvores no Jardim da Saúde, sendo que na Vila Vera este indicativo era 38,68 m, portanto o afastamento médio da Vila Vera seria 2,29, na média do bairro, maior do que o existente no Jardim da Saúde. Em praticamente a totalidade dos indicativos qualitativos o Jardim da Saúde apresentava melhores avaliações das encontradas na Vila Vera, havendo neste segundo local, maiores impedimentos ao adensamento de plantios em função das características do espaço existente. / An tree qualitative and quantitative study was conducted in two closely located neighborhoods (Vila Vera and Jardim da Saude) in the southeast region of São Paulo. In spite of geographical vicinity, both neighborhoods have very different land occupation characteristics. In Jardim da Saude we found 1033 tree specimens, belonging to 72 distinct botanic species, with an average height of 8,07m and average first bifurcation height of 1.97m. Caesalpinea peltophoroides Benth was the most frequent species found (20,68% of the trees), followed by Lagestroemia indica L. (with 7,48% of the trees), and Legustrum lucidum W.T. Aiton coming in third place (with 6,89% of the trees). Those three species together account for 35.05% of the specimens. 72.80% are located in sidewalks that are between 1.00m and 2.00 m wide. Most trees have a height of 8,50 m and above. The worst health threat was termite infestation which affected 8.33% of the specimens. 13.65% were noted to have poor crown quality, 20.62% presented some indication of poor trunk quality and only 23.33% of the trees where planted in an area which enough surface permeability. 5.71% of the specimens had been pruned to prevent interference with electrical lines and crown-reducing pruning had been done in 7.74% of the trees. In Vila Vera we found limited space conditions in regards to the width of the sidewalk and also in regards to the predominant type of site utilization. Residential buildings constructions usually advance far into the sidewalk, with a driveway for access to the garages which are usually located in the front side of the building. We counted 178 trees belonging to 42 distinct botanic species, with average height of 6.31m and first bifurcation average height of 1.81m. The most common species is Caesalpinea peltophoroides Benth. (Which accounted for 24.71% of the specimens), followed by a Legustrum lucidum W.T. Aiton (with 17.24%) and Lagerstroemia indica L. in third place (with 8.62%). In this neighborhood 42.70% of the trees had a height of less than 4.5m, 12.37% were in poor health due to termite infestation, 55.62% are located in sidewalks with widths varying between 1.00 and 2.00 m, 50.0% displayed poor crown quality and 25,44% presented some indication of poor trunk quality. Only 7.87% of the specimens where planted in an area which enough surface permeability, while 16.85% where located in totally paved areas. 3.38% had been pruned to avoid interference with electrical lines and 13.48% had been crown-reducing pruned. In Jardim da Saude the average distance between trees was 16.85m, while in Vila Vera it was 38.68m. In other words, the average distance between trees is about 2.29 greater in Vila Vera than in Jardim da Saude.. Practically all the qualitative domains were found to be superior for Jardim da Saude. Vila Vera also presents greater impediments for increasing planting density due to its current space availability issues.
79

Estudo do microclima e conforto térmico proporcionado por cinco espécies de árvores urbanas do município de Gurupi, TO

Pérez, Cláudia Alicia Marín 21 March 2017 (has links)
A vulnerabilidade ao estresse térmico, uma das principais causas do desconforto humano, pode ser um dos elementos chaves, nos centros urbanos em regiões de climas quentes. Neste cenário, a arborização urbana é considerada uma das ferramentas na mitigação deste efeito, sobre o ambiente urbano. Para tal efeito, esta ferramenta precisa de maior informação sobre a consequência que as árvores produzem nas imediações em termos de redução do estresse térmico e sobre a variabilidade deste efeito com as espécies e as estações do ano. Neste trabalho objetivou-se caracterizar e analisar o microclima e o conforto térmico, nas imediações de cinco espécies de árvores Pachira aquática Aubl.(Monguga); Mangifera indica L.(Mangueira); Caesalpinia pluviosa DC.(Sibipiruna); Syzygium malaccense (L.) Merr. & LMPerry (Jambo vermelho) e Licania tomentosa (Benth.) Fritsch (Oiti), localizadas no setor central de Gurupi, Tocantins no ano 2016. As variáveis microclimáticas consideradas foram: temperatura, umidade relativa, e velocidade do vento, registradas através de uma estação meteorológica portável, marca Skymaster, modelo SM-28, às distâncias: 0 m (sombra), 5 m, 10 m e 15 m (sol) do fuste da árvore, nos horários 10:00 h, 12:00 h e 14:00 h. A caracterização do conforto térmico se baseou no índice de calor e na carta bioclimatica de Olgyay adaptada a climas quentes. Todas as variáveis foram consideradas no espaço atingido pelo efeito da árvore e analisadas estatisticamente. Com respeito ao índice de calor, a média do estudo foi de 34±1,1°C categorizado como “cuidado extremo”, ao passo que no período úmido dos meses outubro e dezembro a média esteve próxima à categoria: “cuidado”. Também se observaram atenuações de temperatura de 0,5ºC e de 2ºC entre a sombra e o sol, com probabilidades de 0,76 e 0,53, respectivamente. Das espécies estudadas, a Mangueira foi a que mais contribui para atenuações de 0,5ºC (p=0,92) e de 2ºC (p=0,67). O período seco foi analisado particularmente por ser considerado crítico termicamente, encontrando-se destaque das espécies Oiti, Mangueira e Sibipiruna. Com relação ao conforto térmico, pela carta de Olgyay mostrou-se que na sombra o conforto pode ser atingido desde que tenha ventos superiores aos 1ms-1. Pelos resultados podem-se inferir efeitos positivos de todas as árvores presentes na arborização urbana com as características das espécies estudadas. / The vulnerability to thermal stress, one of the main causes of human discomfort, may be one of the key elements in urban centers in hot climates. In this scenario, the urban forestry is considered one of the tools for mitigating this effect, in the urban environment. For this purpose, this tool needs for more information about the consequence that the trees produce in the vicinity in terms of reduction of thermal stress and on the variability of this effect with the species and the seasons of the year. The objective of this work was to characterize and analyze the microclimate and the thermal comfort, in the vicinity of five tree species Pachira aquática Aubl.(Monguga); Mangifera indica L.(Mangueira); Caesalpinia pluviosa DC.(Sibipiruna); Syzygium malaccense (L.) Merr. & LMPerry (Jambo vermelho) e Licania tomentosa (Benth.) Fritsch (Oiti), located in the central sector of Gurupi, Tocantins in the year 2016. The considered microclimatic variables were: temperature, relative humidity, and wind speed; recorded through a portable weather station, brand Skymaster, Model SM-28, at distances: 0 m (shade), 5 m, 10 m and 15 m (sun) from the shaft of the tree, at 10:00 h, 12:00 h and 14:00 h. The characterization of thermal comfort was based on the heat index and Olgyay bioclimatic chart adapted for hot climates. All variables were considered in the space affected by the tree effect and analyzed statistically. Regarding the heat index, the mean of the study was 34±1.1°C, categorized as "extreme caution", while in the wet period from october to december the average was close to the category: "caution". There were also observed attenuations of 0.5°C and 2°C between the shade and the sun, with probabilities of 0.76 and 0.53, respectively. Of the studied species, Mangueira contributed the most to attenuations of 0.5ºC (p=0.92) and 2ºC (p=0.67). The dry period was analyzed particularly as being considered thermally critical, with prominence of the species Oiti, Mangueira and Sibipiruna. Regarding the thermal comfort it was shown by the chart of Olgyay that in shade comfort can be reached providing winds higher than 1ms-1. From the results can be inferred positive effects of all the trees present in the urban arborization with the characteristics of the studied species.
80

CONCEPÇÕES DOS ALUNOS DO ENSINO MÉDIO E SUPERIOR SOBRE ARBORIZAÇÃO URBANA INSERIDAS NO CONTEXTO DA EDUCAÇÃO AMBIENTAL

Marques Junior, Helcio 19 April 2012 (has links)
Made available in DSpace on 2016-08-10T10:44:16Z (GMT). No. of bitstreams: 1 HELCIO MARQUES JUNIOR.pdf: 4575880 bytes, checksum: cec743029345228ebffcfa91cdbaa9d0 (MD5) Previous issue date: 2012-04-19 / The urban forestry and environmental education are very important elements for achieving satisfactory levels of quality of life, because they play ecological, economic and social space in which they operate, providing several benefits to the population. The present study sought to assess the perception of students from high school and university, public and private school, two middle schools (A and B) and two universities (C and D), about the importance of urban forestry, environmental education and the environment. Two questionnaires were used, the first preconceptual to assess students prior knowledge and the second applied after the completion of eight educational interventions on biodiversity, savannah, native species, exotic species, periods of fruiting trees and basics of stock seeds. The results showed that students perceptions about the terms environmental education and the environment still favors the traditional tendency and basically naturalistic view, only the terms relating to natural features. Urban trees on the subject, the conception of the students before the intervention was low, since this had never been given, because of lack of interest by teachers and school funding. After the educational interventions found that student interest was significant, especially on the tree species used in urban forestry in Goiânia and flora of the Cerrado. Regarding environmental issues, it becomes necessary to increase less fragmented and abstract classes on content of the environment so that they can contribute to the learning process. / A arborização urbana e a educação ambiental constituem elementos de suma importância para a obtenção de níveis satisfatórios de qualidade de vida, pois desempenham funções ecológicas, econômicas e sociais no espaço em que estão inseridas, proporcionando vários benefícios à população. O presente estudo pretendeu avaliar a percepção de alunos de nível médio e superior, do ensino público e particular, em duas escolas de nível médio (A e B) e duas universidades (C e D), sobre a importância da arborização urbana, educação ambiental e meio ambiente. Foram aplicados dois questionários, sendo o primeiro pré-conceitual para avaliar o conhecimento prévio dos alunos e o segundo aplicado após a realização de oito intervenções didáticas sobre biodiversidade, cerrado, espécies nativas, espécies exóticas, períodos de frutificação, noções básicas de arborização e banco de sementes. A metodologia baseou-se em questionários contendo questões objetivas e do tipo aberta. Os resultados permitiram observar que a percepção dos alunos sobre os termos educação ambiental e meio ambiente ainda privilegia basicamente a tendência tradicional e a visão naturalista, relacionando os termos apenas aos aspectos naturais. Sobre a temática arborização urbana, a concepção dos alunos antes das intervenções foi mínima, uma vez que esta nunca tinha sido ministrada, em virtude da falta de interesse por parte dos professores e verba escolar. Após as intervenções didáticas observou-se que o interesse dos alunos foi significativo, principalmente sobre as espécies de árvores usadas na arborização urbana em Goiânia e flora do Cerrado. Quanto às questões ambientais, torna-se necessário aumentar a carga horaria de aulas tornando-lhes, menos fragmentadas e abstratas sobre os conteúdos do meio ambiente para que estas possam contribuir para o processo de aprendizagem.

Page generated in 0.1397 seconds