The Study On Relieving Urban Heat Island Effect By Forest Stand In Dongguan

City is a complex system which is developed along with the progress of human civilization, urbanization marks a turning point of modern civilization in a country and a region, which has played a great role in promoting economic and social development and improving the quality of human life. Accelerating the process of urbanization today, with a high urban population denisity and the decreasing of agriculture and forestry land use,while changing the nature of the underlying surface of the city, the high intensity of economic activity consumes a lot of fuel, which can produce greenhouse gases, result of the global warming, affecting the living environment of urban human settles seriously and changing the regional climate conditions, then result the unique microclimate characteristics---Urban Heat Islands which affect the architecture, traffic condition, living environment and even the settles’ healthy. Because of the Deterioration of urban thermal environment, declining in the quality of urban environment, air pollution is hard to spread,which promote a series urban disease and multiple epidemics. With the improving of urban living, people have put forward higher requirements to the urban environment. As a result, as a developing country, in the process of sustainable development in China, the problem of urban environment is the key problem to be solved urgently. The Pearl River Delta region as an important typical area of rapid urbanization in China, the regional thermal environment is obviously affected by urbanization, as a result, to carry out the research on the thermal effect of mitigation is of great significance.Through photosynthesis and transpiration, green plants can regulate the temperature of the air in a certain range, many scholars using meteorological data, remote sensing images and other methods to study the effect of vegetation on the mitigation of urban heat island effect, improving that vegetation cooling effect is obviously. Based on remote sensing data and field survey data in the year of 2004 and 2014 in Dongguan to research the effects offorest stand on mitigrating heat island effect. Using two scene remote sensing images to produce the vegetation distribution map and NDVI image of the year of 2004 and 2014,combined with the measured data and the weather station data to invert the surface temperature, then using Arc GIS software to digital geographical elements at the same time,then analised the mitigration effect of different areas of vegetation and stands, include the cooling effect of different tree species in the same age group, different age group in the same stands and different crown density of the same stands, the results shows that:(1)Using the sixth band of Landsat 5, the eleventh band of Landsat 8 to invert the ground temperature in Dongguan City is feasible,(2)The vegetation of Dongguan city is dominated by other types of green space, between the year of 2004 to 2014, ten years of vegetation coverage increased by 8.57%, and different vegetation types distribution unevenly,(3)The cooling effect of different forest stands was different, arbor forest, especially the broadleaf mixed plantations, cooling effect is the best, but in the same age group of different phase comparison, the cooling effect of the Theaceae is the best, followed by mixed coniferous and broad leaved forest,(4)The cooling effect of different age groups was different in the same stand, the cooling effect of nearly mature forest cooling effect and mature forest obviously,(5)In the comparision of the same forest with different canopy denisty of different stand, most of arbor forest with up to 0.7 canopy denisty have better mitigration effect.