Population growth and urban sprawl have contributed to the formation of significant urban heat island phenomena in Houston, Texas, the fourth largest city in the United States. The population growth in Houston was 25.8% between 1990 and 2000 nearly double the national average. The demand for information concerning the effects of urban and suburban development is growing. Houston is currently the only major US city lacking any kind of comprehensive city zoning ordinances. The Normalized Difference Vegetation Index (NDVI) has been used as a surrogate variable to estimate land surface temperatures at higher spatial resolutions, given the fact that a high-resolution remotely sensed NDVI can be created almost effortlessly and remotely sensed thermal data at higher resolutions is much more difficult to obtain. This has allowed researchers to study urban heat island dynamics at a micro-scale. However, this study suggests that a vegetation index alone might not be the best surrogate variable for providing information regarding the independent effects and level of contribution that tree canopy, grass, and low-lying plants have on surface temperatures in residential neighborhoods. This research combines LIDAR (Light Detection and Ranging) feature height data and high-resolution infrared aerial photos to measure the characteristics of the micro-structure of residential areas (residentialstructure), derives various descriptive vegetation measurement statistics, and correlates the spatial distribution of surface temperature to the type and amount of vegetation cover in residential areas. Regression analysis is used to quantify the independent influence that different residential-structures have on surface temperature. In regard to implementing changes at a neighborhood level, the descriptive statistics derived for residential-structure at a micro-scale may provide useful information to decision-makers and may reveal a guide for future developers concerned with mitigating the negative effects of urban heat island phenomena.

This report analyzes urban tree canopy cover (UTC) in Austin, Texas in 2006 using a Geographic Information System (GIS) geoprocessing method developed by the U.S. Forest Service. Findings reveal where UTC exists, could exist, and where it could be prioritized (physically speaking) throughout the Austin region. Results are explained through the context of natural regions and land use to further characterize the urban forest distribution with the purpose of gaining valuable big-picture insights as to where environmental benefits have resulted from local land use planning decisions, development tendencies, and forestry management practices in Austin. / text

Urban trees are crucial to a healthy environment. The benefits range from good air quality to storm water management and public health. The aim of this thesis was to study urban trees in Umeå city. Umeå is in a process of densification and has a vision to increase in population to 200 000 by the year 2050. During densification, trees are often removed to make space for buildings and streets. To keep track of the trees in an urban area, an analysis of the share of canopy cover can be done. For this thesis, the city enter in Umeå has been analyzed to find out the share of trees, vegetation, imposturous ground, buildings, and water that makes up the land cover. This through a canopy cover analysis using the software i-Tree Canopy. The results show that the overall share of urban trees has decreased since 2007 and the share of buildings have increased, an evident effect of densification. In addition to analyzing canopy cover, the change in amount and location of municipally owned trees has also been analyzed. This analysis presented a contradictory view of urban trees, where the number of trees has increased. A reason for this could be that while the municipality has programs in place to plant and manage trees, privately owned trees are not being monitored. There are obstacles with the aim to increase the number of urban trees in a dense city. The increasing amount of imposturous ground and building makes the environment hard for trees to thrive in. The roots have not enough space to grow, and the trees are prone to damages. This results in trees that does not live very long before they have to be removed and replaced, which has negative effect on the environment. Preserving trees with large canopies and at the same time planting new ones are important parts in keeping a sustainable urban area. Analyzing canopy cover and the change over time is a way to learn and prepare for future urban planning in Umeå.

Thesis (MScFoodSc) Stellenbosch University, 2014 / ENGLISH ABSTRACT: We aimed to determine how canopy position influences fruit quality and consumer preference for the eating quality and appearance of ‘Forelle’, ‘Bon Chrétien’ and ‘Bon Rouge’ pears. Our hypothesis was that consumer preference would be higher for the appearance and eating quality of outer canopy fruit. Our first trial investigated the effect of canopy position and cold storage duration on quality attributes and consumer preference for ‘Forelle’ pears. Mealiness was much more prevalent in outer canopy fruit in 2012 and after 9 and 12 weeks cold storage in 2011. In 2011, consumers preferred the eating quality of inner canopy pears that had been subjected to 12 and 16 weeks of cold storage while inner canopy pears were generally preferred in 2012. This study provides support for the mandatory 12 weeks cold storage of ‘Forelle’ pears. Our second trial investigated the effect of canopy position and harvest maturity within the commercial picking window on the quality attributes and consumer preferences for ‘Forelle’ pears. Inner canopy pears of harvest 1 (23 February) and harvest 2 (27 February) were significantly preferred in terms of eating quality. The general dislike for harvest 3 (13 March) pears and outer canopy fruit seemed to relate to an incidence of mealiness. Our results suggest that harvesting ‘Forelle’ pears at a firmness ≈6.2 kg will ensure that both inner and outer canopy pears have acceptable eating quality. In our third trial, fruit were harvested at commercial firmness from two orchards in each of Elgin and Ceres to assess the effect of orchard site on quality attributes of ‘Forelle’ pears. Total soluble solids (TSS) were higher in Elgin while flavour attributes were more pronounced in Ceres. In both areas, outer canopy pears were higher in TSS and lower in titratable acidity (TA) but canopy position had no effect on sweet and sour taste. Mealiness incidence was high in outer canopy fruit from Elgin, as well as in one Ceres orchard. Further research over consecutive seasons is needed to determine the reasons for orchard differences in mealiness incidence. Our fourth trial investigated the effect of canopy position on quality attributes and consumer preference for ‘Bon Chrétien’ and ‘Bon Rouge’ pears. Despite a higher TSS:TA ratio in outer canopy ‘Bon Rouge’ pears and a higher TSS and dry matter concentration in outer canopy ‘Bon Chrétien’ pears, canopy position did not affect sensory eating quality attributes. Seen overall, results indicate that canopy position has a minor effect on consumer preference for ‘Bon Chrétien’ and ‘Bon Rouge’ eating quality. No significant differences in colour and consumer preference for appearance were found between outer and inner canopy ‘Bon Chrétien’ pears. Consumers slightly preferred the redder outer canopy ‘Bon Rouge’ pears over the less red inner canopy fruit. Although consumers preferred the red blush colour of outer canopy ‘Forelle’ pears, inner canopy pears also received high scores. Inner canopy ‘Forelle’ pears should not be viewed as inferior to outer canopy fruit with regard to both eating quality and appearance. / AFRIKAANSE OPSOMMING: Ons het gepoog om die effek van boomposisie op vrugkwaliteit en verbruikersvoorkeur vir die eetkwaliteit en voorkoms van ‘Forelle’, ‘Bon Chrétien’ en ‘Bon Rouge’ pere te ondersoek. Ons hipotese was dat verbruikersvoorkeur hoër sou wees vir die voorkoms en eetkwaliteit van pere van die buitekant van die boom se blaredak. Ons eerste proef se doelstelling was om die effek van boomposisie en koelopberging op die kwaliteitseienskappe en verbruikersvoorkeur vir ‘Forelle’ pere te bepaal. Melerigheid was beduidend meer aanwesig in buitevrugte in 2012 asook na 9 en 12 weke koelopberging in 2011. Verbruikersvoorkeur vir eetkwaliteit was die hoogste vir binnevrugte na 12 en 16 weke koelopberging in 2011 terwyl binnevrugte in die algemeen voorkeur geniet het in 2012. Hierdie studie steun die bevindinge van vorige studies dat ‘Forelle’ pere vir ten minste 12 weke koelopgeberg moet word. Die doel van ons tweede proef was om te bepaal of ‘Forelle’ pere wat by verskillende ryphede binne die kommersiële oesperiode geoes is, verskille toon in kwaliteitseienskappe en of hierdie verskille, indien enige, verband hou met verbruikersvoorkeur vir eetkwaliteit. Die eetkwaliteit van binnevrugte van oes 1 (23 Februarie) en oes 2 (27 Februarie) is verkies bo buitevrugte. Die algemene afkeur vir oes 3 (13 Maart) en buitevrugte kan moontlik toegeskryf word aan die hoë voorkoms van melerigheid. Ons resultate dui aan dat beide binne- en buitevrugte aanvaarbare eetkwaliteit behoort te hê indien ‘Forelle’ pere by ‘n fermheid van ≈6.2 kg geoes word. Vir ons derde proef is ‘Forelle’ pere geoes by kommersiële fermheid (≈6.4 kg) vanaf twee boorde in elk van Elgin en Ceres. Totale opgeloste vastestowwe (TOV) was hoër in Elgin pere terwyl geur-eienskappe meer prominent was in Ceres pere. In beide areas het buitevrugte hoër TSS en laer titreerbare sure (TS) gehad, maar boomposisie het egter geen effek op soet en suur smaak gehad nie. Die voorkoms van melerigheid was hoog in buitevrugte van die Elgin boorde, sowel as in een van die Ceres boorde. Verdere navorsing oor opeenvolgende seisoene word benodig om redes vir die verskille in die voorkoms van melerigheid tussen boorde te ondersoek. Die doelstelling van ons vierde proef was om die effek van boomposisie op die kwaliteitseienskappe en verbruikersvoorkeur vir ‘Bon Chrétien’ en ‘Bon Rouge’ pere te ondersoek. Ondanks ‘n hoër TOV:TS ratio in ‘Bon Rouge’ buitevrugte en ‘n hoër TOV en droë massa konsentrasie in ‘Bon Chrétien’ buitevrugte, het boomposisie ‘n minimale impak gehad op sensoriese eetkwaliteitseinskappe en verbruikervoorkeur vir die pere. Boomposisie het geen effek op die kleur en verbruikersvoorkeur vir die voorkoms van ‘Bon Chrétien’ pere gehad nie. Verbruikers het ‘n effense hoër voorkeur getoon vir die rooier ‘Bon Rouge’ buitevrugte. Alhoewel verbruikers die aantreklike rooi bloskleur van ‘Forelle’ buitevrugte verkies het, het die groen tot geel binnevrugte ook hoë voorkeurpunte behaal. Rakende voorkoms en eetkwaliteit, is ‘Forelle’ binnevrugte glad nie minderwaardig teenoor buitevrugte nie.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Rise in air pollution resulting in negative health externalities for humans has created an urgent need for cities and communities to monitor it regularly. At present we have insufficient ground passive and active monitoring networks in place which presents a huge challenge. Satellite imagery has been used extensively for such analysis, but its resolution and methodology present other challenges in estimating pollution burden. The objective of this study was to propose three low-cost methods to fill in the gaps that exist currently. First, EPA grade sensors were used in 11 cities across the U.S. to examine NO2. This is a simplistic way to assess the burden of air pollution in a region. However, this technique cannot be applied to fine scale analysis, which resulted in the next two components of this research study. Second, a citizen science network was established on the east side of Indianapolis, IN who hosted 32 Ogawa passive sensors to examine NO2 and O3 at a finer scale. These low-cost passive sensors, not requiring power, and very little maintenance, have historically tracked very closely with Federal Reference Monitors. Third, a low-cost PurpleAir PA-II-SD active sensors measuring PM2.5 were housed with the citizen scientists identified above. This data was uploaded via Wi-Fi and available via a crowd sourced site established by PurpleAir. These data sets were analyzed to examine the burden of air pollution. The second and third research studies enabled granular analyses utilizing citizen science, tree canopy data, and traffic data, thus accommodating some of the present limitations. Advancement in low-cost sensor technology, along with ease of use and maintenance, presents an opportunity for not just communities, but cities to take charge of some of these analyses to help them examine health equity impacts on their citizens because of air pollution.

No description available.

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.

No description available.

The thesis focuses on the study of arboreal ant communities in a highly diverse tropical rainforest in Papua New Guinea. In the first study of its kind, whole patches of forest were sampled extensively for ants foraging and nesting in tree trunks and canopies. An extraordinary amount of material collected from 684 felled trees and 260 bait stations in plots of primary and secondary forest was used to study the mechanisms structuring the diversity and species coexistence of this ecologically important insect group at the local scale. The first chapter addresses the question "Why are ant communities more species rich in primary than in secondary forests?" and explores the main environmental traits that influence their diversity in tropical trees. The second chapter compares the community diversity and composition and nesting preferences of ant species between both forest types. The final third chapter introduces a novel method, involving large-scale manipulation of ant communities that could serve as a template for future studies focused on complex tropical food-webs of canopy arthropods and plants. In summary, the results of the thesis highlight the importance of primary vegetation in conserving the diversity of native ant communities and the relevance of nesting microhabitats and their turnover between trees, rather than tree taxonomic diversity, for sustaining the diverse arboreal fauna in tropical forests.