Studies On The Evolution Of Living Vegetation Volume In The Urban Parks Of Wuhan

With the accelerated pace of urbanization,the construction land is expanding rapidly,green space and farmland in peri-urban area are continuing to decrease.Green space inside the city is constantly changing with urban renovation.This research selected 30 parks in the main city of Wuhan as the research objects.with the support of hemispheric photography technology and "3S" technologies,through the remote sensing analysis of Landsat satellite images of 1994,2000,2004,2009,2014,extracting land cover types and vegetation index information of the main city of Wuhan in each period,and establishing inversion model with field measurement data,this study extracted vegetation information and analyzed the change rules,characteristics,transfer regularity and influence factors of LVV at three levels:single,classification and entirety.The main conculsions are as follows:(1)The degree of clarity and brightness of the samples are two core parameters when measuring Leaf area index using HemiView canopy analysis instrument.It can effectively improve the clarity and brightness of samples by tree steps:slow two grades of shutter speed after photometry under AV mode,set diaphragm as 11 and select automatic focusing mode.(2)Normalized vegetation indices are significantly associated with Leaf area index.It reduced the volatility of data,enhanced data stability and improved the retrieval accuracy by using Log processing method.The best retrieval model is Y=e(2 043-1.449/x).(3)The area of the whole park has been increased,and the average annual growth rate increases year by year.The LVV and GVR of the whole park are also on the up trend,but the growth rate is slowing.Low amount of LVV and medium amount of LVV decreased between 1994 and 1999,whereas high amount of LVV significantly increased.Since 1999,low amount of LVV was less volatile,high amount of LVV showed a trend of decline,but the speed was slower and slower.Medium amount of LVV present a tendency of increasing,and the speed was reducing.(4)The LVV of G111,G132 and G137 park were increasing between 1994 and 2004,the growth rate of G111 park was slowing,conversely the speed of G132 and G137 park was rising.The LVV of the three one were reduced and continued to increase since 2009.G112 park is relatively stable so that its LW and GVR increased year by year.The LW and GVR of G135 park were increasing between 1994 and 2009,but the growth rate was slowing constantly,and the LVV of G135 park began to decrease after 2009.The LW and GVR of G14 park decreased abit,thenincreasedever since.(5)The LW and GVR of Jiefang Park showed a trend of increase-decrease-increase The reason why the LW decreased in 2009 might be due to the renovation from November 2005 to September 2006.The LW and GVR of Hankou Marshland was broadly unchanged between 1994 and 1999,and then increased rapidly after 1999,this might caused by the combination of new green space and the development of green space.The LW and GVR of East Lake Park firstly increased and then decreased,the gross amount of LVV began to decrease since 2004 because of the construction of East Lake tunnel,Fruit-Lake tunnel and Wuhan railway station(6)The number,area and the renewal of urban parks are the three important factors in the process of urban parks’ LW evolution.