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" Effect of trees in ameliorating air temperature in urban settings of Pakistan "
A. Zahoor
J. H. Ehrenreich
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Latin Dissertation
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English
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| Record Number
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1113516
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TLpq304351724
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| Main Entry
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A. Zahoor
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J. H. Ehrenreich
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| Title & Author
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Effect of trees in ameliorating air temperature in urban settings of Pakistan\ A. ZahoorJ. H. Ehrenreich
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| College
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University of Idaho
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| Date
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1997
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| student score
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1997
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| Degree
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Ph.D.
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| Page No
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183
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| Abstract
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Rising temperature is one of the pressing problems of cities in Pakistan. On hot summer days, one can feel the waves of blistering heat emanating from roads and dark buildings which keep urban areas hot, even long after the sun has set, while the rural areas have already begun to cool rapidly. Tree plantations in cities in developed countries are becoming part of the comprehensive urban planning process. Urban planning can incorporate these natural elements to help solve the pressing urban problem of rising temperature. In today's complex urban environment, tree planting is something that also has to be emphasized in semi-tropic areas such as Pakistan. Strategical planting of trees to lower summer temperature in urban areas of Pakistan has not been proposed and emphasized so far mainly because of: (1) deficiencies in knowledge about the importance of trees in urban environments among enforcing authorities and the public, and (2) lack of public participation in urban tree planting due to ecological illiteracy. The lack of attention to urban trees in Pakistan can be well documented by visiting the cities. Understanding the relationship between urban trees and the environment can help to improve the urban design and increase the public's awareness of the importance of trees in their living environment. They reduce stress produced by the heat island, decrease noise levels, filter out certain pollutants, and reduce residential energy use. There is no formal governmental policy about urban trees in Pakistan at the national, provincial, or city levels unlike in most European countries and in the United States. Today in Pakistan, the energy crisis due to a shortage of resources for power generation provides a new impetus to re-explore the relations among climate, architecture, and urban trees. In view of the remarkable rate of urbanization in Pakistan since independence the impact of urbanization on local temperature and the role of trees in ameliorating urban temperature were studied. This study comprised three parts: (1) evaluation of the impact of urbanization on local temperature, (2) determination of the potential for reducing urban air temperatures through vegetative cooling, and (3) estimation of the impact of tree shading on the internal temperature of buildings through computer modeling. The results indicate there is clear evidence of a change in the urban temperature excess over time. The heat island effects of the city are more noticeable during the summer season. The mean intensity of the urban heat island effect is about 2.9F during the summer season and the overall annual increase in temperature in the last 120 years is 2F. It was found that trees have significant impact on local temperature and are effective in reducing temperature even during high temperature hours. It was estimated that vegetation may lower urban temperatures by 6-7F and that internal temperature of buildings can be significantly reduced by tree shading. It was also found that a negative linear relationship exists between the internal temperature and the amount of shading. From a policy-making perspective, increased tree cover would therefore be helpful in reducing both outside and internal temperatures of buildings.
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| Subject
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Area planning development
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Biological sciences
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Communication and the arts
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Forestry
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Social sciences
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Urban planning
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