Patterns and dynamics of urban forests in relation to land use and development history in Guangzhou City, China

Trees in cities display a varied pattern that is often moulded by a city's physical fabric and its evolution through time. The town plan expressed in spatial dimension as land use, and in temporal sense as development history, furnishes a framework to evaluate the intricate association between city and trees. Guangzhou city, the premier metropolis of south China, has been established for 2800 years, and has a long history of urban greening and heterogeneous land use. Five urban districts, which represent old, middle-aged and young stages of development and cover the bulk of the city's built-up zones, form the study area. Interpretation of aerial photographs is used as a basis to classify the urban forest into three types, and to design a sampling scheme for studying trees in urban parks, institutional grounds and roadsides. District history has bequeathed a plethora of configurations in terms of buildings, roads and land uses, accompanied by plantable spaces of dissimilar dimensions, geometry and quality. The districts display diverse tree attributes such as frequency, density and species diversity. Young districts, with lower density, more institutional uses and wider roads, present more opportunities for greening. Recent shifts in landscape fashion have introduced a significantly different treescape. A few exceptionally large parks and institutional sites play a pivotal role in the city's tree assets. Parks, roadsides and institutional forests have different tree-stocking rates and species assemblages. Implications for future planting and management of urban trees in different situations, and for the greening of other cities in China, and other developing countries, are explored.     

Exploring spatial-temporal change and gravity center movement of construction land in the Chang-Zhu-Tan urban agglomeration

Urban agglomeration is caused by the continuous acceleration of the urbanization process in China. Studying the expansion of construction land can not only know the changes and development of urban agglomeration in time, but also obtain the great significance of the future management. In this study, taking Changsha-Zhuzhou-Xiangtan (Chang-Zhu-Tan) urban agglomeration in Hunan province as a study area, Landsat images from 1995 to 2014 and Autologistic-CLUE-S model simulation data were used. Moreover, several factors including gravity center, direction, distance and landscape index were considered in the analysis of the expansion. The results revealed that the construction area increased by 132.18%, from 372.28 km² in 1995 to 864.37 km² in 2014. And it might even reach 1327.23 km² in 2023. Before 2014, three cities had their own respective and discrete development directions. However, because of the integration policy implementation in 2008, the Chang-Zhu-Tan began to gather, the gravity center moved southward after 2014, and the distance between cities decreased, which was in line with the development plan of urban expansion. The research methods and results were relatively reliable, and these results could provide some reference for the future land use planning and spatial allocation in the urbanization process of Chang-Zhu-Tan urban agglomeration.

     

Assessing Natural and Cultural Determinants of Urban Forest Quality in Nanjing (China)

This study assessed underlying natural and cultural determinants of tree health and ways to improve urban forest performance in compact Nanjing city. Two groups of factors were investigated: (1) habitat conditions, including planting site, ground-cover, land cover, and district; and (2) tree traits, including species provenance and seasonality, and tree dimensions. A stratified sampling strategy selected 6351 trees for detailed assessment. The data were analyzed by multivariate logistic regressions. Institutional, park-garden and industrial trees with more open-space sites with vegetated ground-cover performed better than roadside and residential ones. Poor trees in confined residential sites deviated from those in other cities. Park-garden sites did not always nurture meritorious, large and diversified trees. District differentiation in tree performance was related to land cover. Exotic and evergreen species grew better than indigenous and deciduous, offering hints on species-habitat matching. Detailed field and statistical analyses could yield tree-environment information to enhance urban forestry research and management.     

不同职能城市土地利用结构影响因素分析

根据2007年地级以上城市的土地和社会经济数据,采用主成分、聚类分析、相关分析等方法,分析不同职能城市土地利用结构特征及影响因素。结果表明:(1)根据城市职能主因子得分,结合城市规划及发展实际,将地级以上规模城市分为区域综合性城市、第二产业城市、交通城市、文化旅游城市、地方中心城市5类。(2)不同职能城市土地利用结构信息熵以中等水平为主,土地利用类型多样性提升空间较大。(3)经济因素、产业结构、基础设施和城市人口等是影响土地利用结构的主要因素,但对不同职能城市用地结构的影响次序和影响程度异质性明显。     

黄河流域城市群扩张的时空格局演化及情景模拟——以呼包鄂榆城市群为例

黄河流域城镇扩张对区域景观格局影响显著,城市群人口聚集与增长引发了流域“人-地”矛盾和“空间冲突”等一系列生态环境问题。基于土地利用数据和FLUS模型对2025年和2035年呼包鄂榆城市群城镇化与土地利用时空演化特征进行多情景模拟预测。结果表明：① 1990—2018年呼包鄂榆城市群整体发展水平较低,建设用地面积经历了“平稳增加-缓慢增加-急剧增加”的变化过程,区域总体以草地为主,其占土地总面积的50%以上,其次是未利用土地和耕地,林地和建设用地次之。② 城市群扩张最剧烈地区在空间上主要发生在呼和浩特市、包头市等城市主城区,且扩张模式以外延式扩张为主,扩张来源主要是耕地、草地等生态用地。③ 三种情景模拟发现,2025年和2035年区域土地利用变化的空间结构和特征差异明显。自然发展情景下,城市扩张不受约束,高速增长占据了大量生态用地;加入生态约束条件很好的控制了对草地和林地的占用;经济发展情景下,城市扩张将进一步占据更多的未利用土地和耕地。本研究通过城市群扩张时空格局演化及情景模拟分析,尝试为区域规划、城市空间规划和区域生态空间保护提供多角度、多情景和可选择的政策决策参考。     

北京城市蔓延的测度与分析

Concerning about the rapid urban growth in recent China, this study takes Beijing as a case and puts forward that urban sprawl can be measured from spatial configuration, urban growth efficiency and external impacts, and then develops a geo-spatial indices system for measuring sprawl, a total of 13 indicators. In order to calculate these indices, different sources data are selected, including land use maps, former land use planning, land price and floor-area-ratio samples, digitized map of the highways and city centers, population and GDP statistical data, etc. Various GIS spatial analysis methods are used to spatialize these indices into 100m×100m cells. Besides, an integrated urban sprawl index is calculated by weight sum of these 13 indices. The application result indicates that geo-spatial indices system can capture most of the typical features and interior differentia of urban sprawl. Construction land in Beijing has kept fast growing with large amount, low efficiency and disordered spatial configuration, indicating a typical sprawling tendency. The following specific sprawl features are identified by each indicator: (1) typical spatial configuration of sprawling: obvious fragmentation and irregularity of landscape due to unsuccessful enforcement of land use planning, unadvisable pattern of typical discontinuous development, strip development and leapfrog development; (2) low efficiency of sprawl: low development density, low population density and economic output in newly developed area; and (3) negative impacts on agriculture, environment and city life. According to the integrated sprawl index, the sprawling amount in the northern part is larger than that in the southern, but the sprawling extent is in converse case; most sprawling area include the marginal area of the near suburbs and the area between highways, etc. Four sprawling patterns are identified: randomly expansion at urban fringe, strip development along or between highways, scattered development of industrial land, leapfrog development of urban residence and industrial area.     

中国城市群城市用地扩张时空动态特征

认识城市群城市用地扩张特征、扩张质量及景观生态效应等综合信息将有助于城市群空间高质量发展规划与决策。选取10个不同发育等级的城市群作为研究对象,综合运用城市用地扩张强度指数、城市用地扩张强度差异指数、景观扩张指数、景观格局指数,分析1990—2015年期间城市群城市用地扩张时空特征及景观生态效应,并构建人口、经济与城市用地协同发展指数,据此分析城市用地扩张中“人—地”关系协同程度。结果表明：① 1990—2015年,各个城市群城市用地面积持续增加,建成区的范围不断扩大,扩张强度呈现“上升—下降”的趋势;在2010年之前成熟型城市群的扩张强度最高,2010年之后培育型城市群成为扩张强度最高的类型。② 城市群城市用地扩张总体上呈现不均衡布局的趋势,高速扩张区域主要分布在沿海地区。从全国视角来看,东部高于中、西、东北部,整体城市群快速扩张的中心由东向西移动。③ 城市群城市用地空间扩张模式表现出边缘式和飞地式两种空间扩张模式并存,不同发育等级之间具有明显差异性,成熟型城市群的空间结构较为稳定,其他两种类型的城市群空间结构初具雏形或尚未形成。④ 城市群城市用地扩张“吞没”了郊区和农村地区,破碎化程度、形状的复杂程度较高,景观格局表现出不稳定。⑤ 城市群“人口—土地”协同程度逐步增强,“经济—土地”协同程度整体较高,整体上表现出城市用地扩张质量有所提升。新时期城市群城市用地应严格控制扩张规模,加快中小城市的发展,促进城市群城市用地扩张均衡发展,为城市群国土空间高质量发展提供重要参考。     

基于遥感影像的甘达基流域博卡拉和巴拉普尔的土地利用变化及其驱动力研究（英文）

城市扩张是反映经济增长的重要指标,但随意的城市扩张也带来了严重的社会经济问题、环境问题以及城市土地管理问题。在这个背景下,理解城市扩张的过程对于指导城市的可持续增长具有重要意义。本研究采用基于遥感影像的监督分类方法,分析了甘达基流域内的两个大城市—博卡拉和巴拉普尔1990–2018年的城市用地变化。结果表明:在过去的28年,博卡拉和巴拉普尔的城市面积分别显著扩张了300%和近500%。人口增长、城市基础设施和便利的生活方式引起周边地区向城市的人口迁移,是造成本研究区城市扩张的主要原因。除此之外,不断变化的城市定义和城市边界的扩张是造成城市快速扩张的关键因素。由于上述两个城市拥有高水平的商业活动以及现代化的设施,未来城市规模可能继续扩大。应当通过城市规划和政策减少随意的城市扩张,从而实现城市的可持续发展。     

Measuring urban sprawl in Beijing with geo-spatial indices

Concerning about the rapid urban growth in recent China, this study takes Beijing as a case and puts forward that urban sprawl can be measured from spatial configuration, urban growth efficiency and external impacts, and then develops a geo-spatial indices system for measuring sprawl, a total of 13 indicators. In order to calculate these indices, different sources data are selected, including land use maps, former land use planning, land price and floor-area-ratio samples, digitized map of the highways and city centers, population and GDP statistical data, etc. Various GIS spatial analysis methods are used to spatialize these indices into 100m×100m cells. Besides, an integrated urban sprawl index is calculated by weight sum of these 13 indices. The application result indicates that geo-spatial indices system can capture most of the typical features and interior differentia of urban sprawl. Construction land in Beijing has kept fast growing with large amount, low efficiency and disordered spatial con-figuration, indicating a typical sprawling tendency. The following specific sprawl features are identified by each indicator: (1) typical spatial configuration of sprawling: obvious fragmenta-tion and irregularity of landscape due to unsuccessful enforcement of land use planning, unadvisable pattern of typical discontinuous development, strip development and leapfrog development; (2) low efficiency of sprawl: low development density, low population density and economic output in newly developed area; and (3) negative impacts on agriculture, en-vironment and city life. According to the integrated sprawl index, the sprawling amount in the northern part is larger than that in the southern, but the sprawling extent is in converse case; most sprawling area include the marginal area of the near suburbs and the area between highways, etc. Four sprawling patterns are identified: randomly expansion at urban fringe, strip development along or between highways, scattered development of industrial land, leapfrog development of urban residence and industrial area.     

重庆市主城区物流园区空间布局及其对城市空间结构的影响

选择现代物流业相对发达的西部地区的中心城市—重庆主城区为典型案例,通过对物流园区实地调研与管理部门的访谈获取论证数据展开案例实证。重庆市主城区的物流园区的案例研究发现：① 物流园区的空间布局具有两大特征：一是围绕城市中心区外围布局,二是沿交通干线或重要交通设施布局;② 物流园区的自身建设是城市开发的重要组成部分,其空间布局对城市空间结构的影响一方面促进和引导城市建成区的向外扩张,另一方面体现在物流园区通过自身建设和对周边地区的带动改变城市的用地结构和内部用地功能。最后分析总结了物流园区对城市空间结构影响的4种机制：垄断机制、配套机制、地价机制和聚集机制。     

Spatio-temporal characteristics of intra-urban land cover in the cities of China and USA from 1978 to 2010

Urban land cover has major impacts on a city''s ecosystem services and the inherent quality of its urban residential environment. The spatio-temporal distribution of impervious surface area and green areas in Chinese cities has exhibited a significantly marked difference in comparison with USA cities. This study focused on monitoring and comparing the spatio-temporal dynamics, land cover patterns and characteristics of functional regions in six Chinese (n=3) and USA (n=3) cities. The study data were collated from Landsat TM/MSS imagery during the period 1978-2010. Results indicate that Chinese cities have developed compactly over the past three decades, while development has been notably dispersed among USA cities. Mean vegetation coverage in USA cities is approximately 2.2 times that found amongst Chinese urban agglomerations. Land use types within Chinese cities are significantly more complex, with a higher density of impervious surface area. Conversely, the central business district (CBD) and residential areas within USA cities were comprised of a lower proportion of impervious surface area and a higher proportion of green land. Results may be used to contribute to future urban planning and administration efforts in both China and the USA.     

沈阳市城市扩展与土地利用变化多情景模拟

利用基于遥感手段获取的沈阳市城市扩展与土地利用变化历史数据,对SLEUTH城市扩展模型进行校正,对未来(2005~2030年)不同管理情景下的城市扩展与土地利用变化过程进行模拟,并对其发展变化趋势和生态环境影响进行分析与比较。结果显示,在三种管理情景下,未来的沈阳市城市建设用地都将持续增加,大量的耕地资源被侵占;但不同管理情景下,城市景观格局和区域面临的景观生态风险却表现出明显差异。SLEUTH模型的模拟结果较好地反映了沈阳市不同土地利用政策、规划方案等对未来城市扩展和土地利用变化以及区域景观生态风险的潜在影响,同时也指出了当前城市增长管理政策中存在的不足之处。     

北京城市蔓延的测度与分析

针对现阶段我国城市用地快速扩张和无序蔓延的现实问题, 以北京市在1996~2004 年期间的城市扩展作为研究案例, 提出可以从城市扩展形态、扩展效率和外部影响等三个方面来判识城市蔓延现象, 并提出基于地理空间指标体系的城市蔓延测度方法, 主要由涉及人口、经济、土地利用、农业、环境和城市生活等方面的13 项指标所组成。实证分析结果表明, 该方法可以有效地测度和量化研究区城市蔓延的特征: ① 建设用地斑块具有明显的破碎化和不规则化趋势, 缺乏良好的规划控制, 不连续开发、条带式开发和跳跃式开发特征明显, 扩展形态不尽合理; ② 新增建设用地的建设密度和容积率较低, 并且新增用地的人口密度和经济产出水平均低于原有用地绩效, 扩展效率不高; ③ 城市蔓延占用大量的耕地和开敞空间、加重了交通负担, 对农业、环境和城市生活存在显著的负面影响。     

2000–2015年京津走廊耕地和建设用地变化监测研究（英文）

Rapid peri-urbanization has become a new challenge for sustainable urban-rural development worldwide. To clarify how unprecedented urban sprawl at the metropolitan fringe impacts urban-rural landscape, this study took the Beijing-Tianjin corridor of Beijing-Tianjin-Hebei metropolitan area, one of the largest urban clusters in China, as a typical example. By using Landsat-based landscape metrics and a practical methodology, we investigated the landscape changes and discussed the potential reasons in the context of rapid peri-urbanization of China. Specifically, multi-temporal land use maps derived from Landsat images were used to calculate landscape metrics and analyze their characteristics along the urban-rural gradients. The practical methodology was used to monitor spatio-temporal characteristics of landscape change in large metropolitan areas. The results showed that landscape patterns in the area had changed greatly from 2000 to 2015 with characteristics of construction land sprawl and arable land shrinkage. The intensity and scale of landscape changes varied along the urban-rural gradients. Sampled plots in urbanized areas and rural areas demonstrated distinguishable landscape patterns and significant differences. Urban areas had more heterogeneous and fragmented landscapes than rural areas. Peri-urban areas in general experienced higher levels of land diversification than rural areas. Rural residential land appeared to be more aggregated near Beijing and Tianjin cities. Besides, our findings also indicated that urban expansion was largely responsible for landscape patterns.The findings of this study potentially provide strategical insights into landscape planning around mega cities and sustainable coordinated urban-rural development.     

从人口低估角度看:发展中国家大城市规划为什么很难成功?（英文）

在发展中国家,多种多样的规划被用来控制大城市的扩展和城市人口增长,然而,这些规划的界线屡屡被突破。当前,已有很多国内外文献对规划失败的原因展开了研究,本文对这些原因进行了梳理,可以归纳为以下几个方面:城市规划不系统、不科学;政府执行不到位;城市化或经济发展过快等。本研究对主要发展中国家大城市规划人口和现实人口进行了归纳和对比,认为城市人口的低估是大城市规划难以实现的一个关键因素。最后,利用世界上110个国家60年(1950–2010年)的数据,分析了各个国家首位城市人口和各国城市化水平及国土面积之间的关系,基于此,一个简要的预测模型被用来预测世界主要国家大城市的人口;为了更好地预测各国首位城市人口的数量,本文还设立了4个哑变量。预测结果与现实人口的对比显示:模型具有较高的预测精度。     

1990—2014年印度城市扩张时空特征对比分析

印度是人口仅次于中国的发展中国家,也是“一带一路”倡议的重要节点。印度正处于城市化快速发展阶段,分析印度城市化特征具有重要意义,而中国国内关于印度城市化和城市扩张的研究和报道相对较少。论文选取10个人口超过100万的印度城市,获取1990、2000和2014年基于Landsat影像的土地利用数据和人口数据,采用圈层分析法将城市划分为等间距的同心圆圈层后统计各圈层内建设用地密度,选取增长率、密度、强度以及景观指数指标对印度城市扩张进行多维度对比分析。研究发现：①城市土地扩张快于人口增长,1990—2000、2000—2014年土地年均增长率分别是人口年均增长率的3.27和2.43倍。②建设用地密度随着与城市中心距离增加而衰减,且在一定距离内快速下降;同圈层内建设用地密度随时间逐渐增加;城市以分散的方式向外扩张,城市形态变得更加松散,特别是在第二阶段(2000—2014年)。③建设用地斑块破碎化程度与城市扩张强度的空间变化相吻合。城市扩张最活跃区域与景观破碎度最严重区域都随时间不断向外推进,城市扩张对景观格局产生显著影响。在全球城市扩张背景下,研究结果将为理解城市扩张时空特征而提供印度样本,也将为研究其他地区城市扩张提供分析方法和思路。     

深圳城市规划对土地利用的调控效能

城市规划实施效能研究已开始由定性走向定量,引入GIS空间分析技术,利用相关政府部门提供的资料和实地调查资料,以深圳为案例从定性与定量角度系统全面地开展了城市规划对土地利用的调控效能研究。研究结果表明城市规划对土地利用调控效果显著:①城市规划对深圳城市空间结构的控制与引导十分有效,使得其在快速发展过程中仍然保持良好的城市空间结构。②城市规划对特区土地利用的调控效果较好,城市建设基本按照规划进行;而城市规划对特区外土地利用基本失控,城市建设无序蔓延,城市规划没有起到应有的调控作用。③城市规划管理对土地利用也具有重要的调控作用,《建设用地规划许可证》的规划审批用地挤占了大量耕地、园地、林地和水域等,引起了深圳各区域土地利用的巨大变化。     

Unplanned urban growth: land use/land cover change in the Guwahati Metropolitan Area,India

Unplanned urban growth, particularly in developing countries has led to changes in land use/land cover (LULC). Numerous Indian cities face problems of unplanned LULC change due to nominal or non-existent planning efforts compounded by rapid urban population growth. The Guwahati Metropolitan Area (GMA) is one such urban centre. The present study assesses the trajectories of LULC change using Landsat imageries acquired in 1976, 1989, 2002 and 2015. Natural and semi natural vegetated area and artificial and natural water bodies decreased while built-up areas, cultivated and managed areas, and natural and semi natural non-vegetated areas increased. The built-up area increased from 23.9 in 1976 to 115.1 km² in 2015 becoming the dominant land cover class accounting for 41.8% of the total geographical area. During this period, natural and semi natural vegetated land were reduced by 88.9 km² at an annual rate of 2.2 km². Over the years there was an increasing trend of built-up land and cultivated and managed areas in the peripheral areas of the city while natural and semi natural vegetated land diminished. Consequently, as in many other developing countries, there is an urgent need for the governmental authorities and other stakeholders to implement effective urban planning policies.     

中国与美国大都市区城市内部土地覆盖结构时空差异

城市内部土地覆盖结构对城市生态服务功能和人居环境质量产生重要影响。中国与美国不同发展阶段城市不透水地表和绿地时空分布格局存在显著差异。本文基于Landsat TM/MSS影像获取1978、1990、2000、2010 年城市内部土地覆盖和不透水地表分类信息,监测并比较中国和美国六个特大城市扩展时空动态、土地覆盖结构差异及城市不同功能区特征。研究表明,在过去30 多年以来,中国城市以相对紧凑形态发展,美国城市较为离散;美国三大城市植被所占的比例是中国的2.21 倍;中国城市内部结构土地利用功能类型更加复杂,不透水地表密度更高,而美国城市CBD和居住区功能相对独立,特别居住区以镶嵌式低不透水地表和高绿地比例结构为主。     

Monitoring land changes in an urban area using satellite imagery,GIS and landscape metrics

Monitoring land changes is an important activity in landscape planning and resource management. In this study, we analyze urban land changes in Atlanta metropolitan area through the combined use of satellite imagery, geographic information systems (GIS), and landscape metrics. The study site is a fast-growing large metropolis in the United States, which contains a mosaic of complex landscape types. Our method consisted of two major components: remote sensing-based land classification and GIS-based land change analysis. Specifically, we adopted a stratified image classification strategy combined with a GIS-based spatial reclassification procedure to map land classes from Landsat Thematic Mapper (TM) scenes acquired in two different years. Then, we analyzed the spatial variation and expansion of urban land changes across the entire metropolitan area through post classification change detection and a variety of GIS-based operations. We further examined the size, pattern, and nature of land changes using landscape metrics to examine the size, pattern, and nature of land changes. This study has demonstrated the usefulness of integrating remote sensing with GIS and landscape metrics in land change analysis that allows the characterization of spatial patterns and helps reveal the underlying processes of urban land changes. Our results indicate a transition of urbanization patterns in the study site with a limited outward expansion despite the dominant suburbanization process.