A Study On Microclimate Effects Of The Urban Forest

To reflect objectively the microclimate effect of the urban forest belt and to boost the environment benefit brought by the urban forest belt in Shanghai, my dissertation centers on the features of the forest belt microclimate effect through the survey of the air temperature, relative humidity, wind speed, wind direction, air ions and noise intensity, directed to the forest belt along the out-ring highway in Pudong in the four seasons from October,2002 to July, 2003.1. The air temperature and humidity effect brought by the forest beltThe lowest temperature in the forest belt was improved in autumn and winter,andthe higest temperature was droped in summer,and the relative humidity was improved in summer . Apparently the forest-belt plays a role in making the summer cooler and moister and the winter warmer and drier.It was reduced by the effect of forest belt about the variation of day temperature of the forest belt in springs summer and autumn , and the variation of day humidity in summer and winter. The forest belt steadies its microclimate of the leeward area from the forest belt.The different effects in forest belt were due to the different structure of forest belt: During the seasons of spring, autumn and winter the lowest temperature in the 100m close-forest belt is higher than that in the wilds ranging in temperature from 0.52 to l.l℃.The survey of the microclimate featured by the forest belt proves that the temperature in the forest belt in spring and summer is 1.4℃ lower than that in the wilds . During the seasons of summer, the averare and lowest relative humidity are higher than that in the wilds by 4% to 14%. During the seasons of spring and summer , the forest belt steadies its microclimate of the north area of the forest belt and the leeward area of 90 meters from the forest belt. The daily variation of temperature are 1.8 ℃ , 0.8℃ , 1.1℃ lower than that in the wilds during the seasons of spring, summer and autumn, and 2.2℃ than that in the wilds in winter. Relatively in summer and autumn the relative humidity and the variation of day temperature in the forest belt are higher by 4.4% to 6.7% than those in the wilds while in winter and spring the relative humidity and the variation of day temperature are lower by 1.1% to 2.6%. It is obvious...