【作者】 胡鸿瑞；

【导师】 吴泽民；

【作者基本信息】 安徽农业大学 ， 园林植物与观赏园艺， 2010， 硕士

【摘要】 本实验运用3S技术并结合现场调查,重点对合肥建成区即二环路以内范围以及包括几个经济开发区在内的整个研究区的城市森林进行研究。利用Arcgis等软件判读卫星图片中城市森林的分布现状;通过LAI反演法建立TM影像上的城市森林的LAI与NDVI之间的回归模型,采用归一化植被指数(NDVI)推算整个研究区城市森林的叶面积指数及占地面积,进而算出叶面积绿量并获得其分布情况。另外,利用Googleearth软件在距地面俯视距离500m处(为树冠轮廓清晰度较佳距离)截图约3200张,并在Photoshop等软件中合成处理,形成研究区范围的航片图,然后圈出树冠图层,得到树冠面积,与平均LAI值相乘得到叶面积绿量;与实测的平均树冠高运算得到三维绿量;同时划分道路、广场、高校机关、中小学校、公园、住宅及其它七个类型图层,分别与LAI分布图、树冠覆盖图相结合,比较不同类型的LAI值、绿量、树冠覆盖率。结果表明:(1)基于遥感数据NDVI指数的城市森林叶面积绿量提取的技术与检测手段,建立了TM影像的NDVI与LAI的回归关系,城市森林LAI与NDVI的关系可以表达为逻辑斯蒂方程,可用于研究周边地区相似森林植被的叶面积绿量。(2)应用WinSCANOPY2006植物冠层分析仪直接测量不同类型城市森林群落的叶面积指数,二环以内平均叶面积指数为2.07 m2/m2,整个研究区平均叶面积指数为2.29 m2/m2。在七种类型的分区中高校机关、中小学校和其他的城市森林LAI值不论是在二环内还是在整个研究区内的平均值都是偏低的的,道路的LAI值较前三者次之,住宅、公园、广场的LAI值偏高。(3)二环以内叶面积绿量为798.18×104m2,城市森林叶面积绿量主要分布在有公园的地区如合肥环城公园,逍遥津公园,其叶面积指数多在2-3 m2/m2之间;整个研究区的叶面积绿量为5159.11×104m2,城市森林叶面积绿量主要分布在研究区的西部和西北部,其叶面积指数多在3-4m2/m2之间,主要因为大蜀山森林;中间除环城公园外叶面积绿量较少。(4)二环以内对绿量贡献率高于城市森林占有率的是住宅、公园、广场;高校机关、中小学校、道路、其它的绿量贡献率均低于城市森林占有率。整个研究区而言,对绿量贡献率高于城市森林占有率的是住宅、公园、广场、道路;其它的绿量贡献率低于城市森林占有率;拥有城市森林面积比与绿量贡献率基本相符的是高校机关、中小学校。(5)二环内所有的树冠覆盖面积占整个二环的比例为8.20%。研究区所有的树冠覆盖面积占整个研究区的比例为6.50%。住宅的树冠覆盖面积虽然最大但树冠覆盖率较低,公园树冠覆盖面积虽不大但树冠覆盖率最高。一环的树冠覆盖率约为一环与二环之间树冠覆盖率的2.2倍,约为二环之外树冠覆盖率的3倍。可见环城内公园中城市森林在合肥市城市森林效益的发挥上起着重要作用。根据城市森林现状,作者认为应保护好中心城区的环城林带,对于人口密度较大的住宅区的绿化应鼓励运用乔木及乔灌木结合的种植设计,增加行道树的种植;注意保护和维持西南和东南部的现有城市森林,调整增加东北和西北区的城市森林面积,改变合肥城市森林分布不均匀的现状;进一步构筑完整的合肥城市森林体系。更多还原

【Abstract】 In this paper 3S technology combined with spot investigation was employed to analyze both Leaf Area Index (LAI) and tree canopy coverage (TCC) of Urban forest patch intensively within the second ring road and several economic developing zones in Hefei, The study area covers about 363km~2. Its current distribution in satellite-pictures is mastered by the means of ArcGis software; Regression model between LAI and Normalized Difference Vegetation Index (NDVI) was built by the inverse method of LAI, where LAI and its area are calculated by the use of NDVI. Then the total leaf area and its distribution pattern in the study area was acquired.Besides, 3200 screenshots intercepted by the tool of Googleearth software at 500 meters high in the sky,a proper resolving power for crown contour distinguish , are composed in the Photoshop software to form a complete aerial photograph of research area. Based on functional classification principles, totally 7 land use categories, such as road, water surface, universities and official organizations, primary and middle schools, parks, residential districts and others, was identified. As Crown contour was made out and leaf area was derived for each land type, the dimensional and three dimensional green quantity was calculated by its area multiplying average LAI and average crown height respectively. The results indicated that:(ⅰ) Based on NDVI of RS data and field measurement of LAI of urban forest using Winscan canopy analyser. the relationship between NDVI and LAI was built in the paper, which was described by logistic equation. This method also could be employed to estimate leaf area in neighboring districts.(ⅱ) Average LAI of 2.07 m~2/ m~2 for urban forest patches within the second ring road was estimated directly using of plant canopy analyzer, and 2.29 m~2/ m~2 in entire research area Among seven land use categories, LAI of urban forest patches in universities and official organizations, primary and middle schools and others, whether within the second ring road or in entire research area, are the lowest, road layer lower, residential districts, parks and public plazas highest.(ⅲ) The total leaf area within the second ring road is 798.18×104 m~2, its main distribution scopes are parks, such as ring park and Xiaoyaojin Park, its LAI are 2-3 m~2/ m~2 in the midst of; The leaf area of whole study area is 5159.11×104 m~2, its main distribution scopes are in western and northwestern part of the city, its LAI are mostly between 3 and 4 m~2/ m~2 , because of Shushan forest park existing in the region.(ⅳ) Within the second ring road, green quantity contribution in residential districts, parks and plazas is higher than that of urban forest coverage; But it is lower in universities and official organizations, primary and middle schools, roads and others. In entire research area, green quantity contribution in residential districts, parks, plazas and roads are higher than that of urban forest coverage; But green quantity contribution in universities and official organizations and primary and middle schools are generally equal to that of urban forest coverage; the others are lower.(ⅴ) The tree canopy coverage reached to 8.2% within the second ring road, yet 6.5% in entire research area. Although total tree canopy area is highest in residential districts, its coverage is lower; Total canopy area in parks is relatively lower but its coverage is the highest.According to the current status of urban forest in Hefei city, the author thinks that we shall protect forest belt round the center city and plant more street trees complying with the design principle of interspersed arbors and shrubs, especially in high density residential districts. Meanwhile, we shall carefully preserve current urban forest in the southwest and southeast of urban area and increase urban forest area in the northeast and northwest to alter its uneven distribution in Hefei. Finally, we shall further construct an intact system of urban forest.更多还原