A time series of urban forestry in Los Angeles

There has been an increasing interest in the evolution of urban forests. This research uses historic and digital aerial photography to quantify changes in tree density in Los Angeles, California since the 1920’s. High-resolution geographic information system analysis (4 to 6 time periods) of three regions (San Fernando Valley, Hollywood, Los Angeles Basin) of Los Angeles reveals that there has not always been an increase in tree density with time. Tree densities on public and private land were highest in the 1940’s in Hollywood, while the San Fernando Valley and Los Angeles Basin experienced a near linear increase in tree density on both private and public land since the 1920’s. When historic tree density reconstructions were examined for the 15 Los Angeles city council districts from the 1920’s, 1950’s and 2006, most districts in Los Angeles have experienced a significant increase in tree density, however, there has been wide variation in tree densities among city council districts. Trees densities have generally been higher on private land since the 1920’s and currently tree densities on private land are significantly higher than on public land. Results suggest the evolution of urban forests in Los Angeles mirrors the dynamics of urban forests in desert and grassland cities. It is possible to reconstruct the development of urban forests in sections of cities using historic and contemporary aerial photography. We estimated that Los Angeles averages approximately 104 trees per hectare (82 private land, 22 public land) based on 2006 imagery at 0.3 m resolution, however, field validation suggests that we identified only 73% of trees. Although there is still space to plant trees on public land, private land owners will need to be heavily involved in order to achieve the goals of Los Angeles’ Million Tree Initiative.     

上海城乡统筹发展的路径和突破口研究

上海城乡二元结构的深层次问题突出表现为:城乡居民收入差距仍然明显,促进农民增收的难度加大;郊区人口持续导入,对公共服务和社会管理的要求提高;农村土地和产权制度改革滞后,深化改革的条件尚不成熟;郊区城市化进程加速,管理体制和管理模式亟待转变;新城和小城镇等城乡统筹载体建设有待加强。上海城乡统筹发展要牢牢把握公共服务均等化、发展成果共享化、发展权利平等化内涵,坚持以城带乡、城乡一体、互动发展,以推进新型城市化战略为主攻方向,以加强城乡规划一体化为前提,以加快新城开发建设为突破口,以土地管理、集体产权、社会管理制度改革为支撑,以基本公共服务均等化为着力点,大力推进工业向园区集中、居住向社区集中、农业向规模经营集中,努力实现优化农村土地资源配置方式、优化城乡资源要素流动方式、优化城乡统筹发展方式,推进城乡一体化发展。     

Gated Communities in Mexico City

ABSTRACT

Based on long-term field research, this article addresses the issue of gated communities in Mexico City as a specific form of the crisis of public space and urban order in a stratified society. By comparing different forms of “gated community,” the paper shows their common characteristics in spite of their morphologic differences. Living in segregated residential spaces in Mexico City is a complex social process which is not only the result of the fear of crime but also a way to escape from urban disorder, to set up islands of social homogeneity and to experiment with new forms of local government.     

Suburban road-closures and the ruinous landscapes of privilege in Johannesburg

In this article we trace the emergence of road-closures – i.e. the barricading by local residents of public roads ostensibly in response to crime – in the northern suburbs of Johannesburg in the decade after apartheid. We argue that road-closures manifest an attempt at material “fixing” an urban order of privilege, even as privilege and inequality is increasingly “deterritorialised” in the city of the global South. While conventionally theorised as part of a broader global trend towards the privatisation and securitisation of urban space, we demonstrate that road-closures contain qualitatively different expectations of the urban order to e.g. private gated communities. Whereas gated communities are premised on and driven by a political economy of self-exclusion from urban life, road-closures simultaneously resist and prefigure this “deterritorialised” reordering of privilege in the post-apartheid city. Based on archival research in local community newspapers over a 10-year period between and 2004 (the high-water mark of the so-called road-closure “debates”), we trace shifting discourses about road closures and the city: from anxieties about crime and loss of privilege, to fantasies of abandonment, to the assertion (and rupture) of a mythical suburban utopia. Drawing on a literature on ruins as the material effects of a past order manifest in the urban order of the present, we assert that despite anxieties about the loss of privilege, these enclosed neighbourhoods remain spaces of extreme privilege, now implicated into an emergent geography in which old and new spaces of privilege overlap to reinforce spatial inequalities in post-apartheid Johannesburg.     

Members Only: Gated Communities and Residential Segregation in the Metropolitan United States1

Using the American Housing Survey for 2001 and Census 2000, I examine the link between gated communities and residential segregation. I hypothesize that gating and segregation are defined by similar mechanisms, thus reinforcing urban inequality in U.S. cities. The results, however, indicate a more complex relationship. On the one hand, there are common mechanisms behind the two processes: the pursuit of higher property values, fear of crime, and fear of increased social heterogeneity. An increase in percent recent immigrants leads to higher levels of both segregation and gating. On the other hand, factors such as region, percent black, percent Hispanic, percent college graduates, and functional specialization affect the two processes differentially. Although segregation is less pronounced and declining in the U.S. urban Southwest, gated communities are much more prominent there. The results challenge the notion that the declines in residential segregation in recent decades indicate social progress.     

城市社区公共空间构筑与基层社会的动员整合——基于上海市G社区的案例分析

城市社区公共空间既是一种物理空间,又是一种制度与文化空间。上海G社区探索楼道公共客厅与楼道居民自治,通过楼道公共空间的拓展与构筑,增强居民归属感,构建居民交流、共商机制,改善社区认同,让社区从一个生活的共同体演变成一种信念的共同体,维护了社区的和谐和稳定,推进基层社会的动员整合。这种社区自治性的成长不仅是社会力量内部整合的基础,也构成了社区共治的基础。由此,未来社区治理的方向是如何建立起社区事务协商参与的多级公共空间,形成共治、自治衔接的有效机制,从而真正实现基层社区国家与社会良性互动、政府行政管理与居民群众自治相衔接的基层社会管理的新格局。     

The Uses and Abuses of Public Space: Urban Governance,Social Ordering and Resistance,Avenham Park,Preston, c. 1850–1901

This article contributes to scholarship on liberal governance during the nineteenth century through the much‐neglected area of the public park. Using Preston as a case study, it seeks to answer why parks were considered necessary, but also to argue for the need to understand micro‐level issues that determined their precise formation and governance. In line with this, attention is paid to how space was orchestrated to encourage self‐regulation, and the elite appropriation of this space to bolster the fragile social order that industrialisation had engendered in the town. Finally attention is paid to the outcome of this, and the ways in which people could enjoy the park, without internalising the intended norms.     

Broadening the Land Question in Food Sovereignty to Northern Settings: A Case Study of Occupy the Farm

Abstract

Land access is an accepted corollary to food sovereignty, long promoted by the transnational agrarian movement La Via Campesina (LVC). LVC's land access politics have evolved with increased incorporation of diverse perspectives, but remain largely focused on achieving ‘integral agrarian reform’ in the global South. Here, I take a case where food sovereignty activists (‘Occupy the Farm’ (OTF)) occupied land owned by a public university in California, the USA, in order to broaden food sovereignty's land access considerations beyond the South, and to analyze conditions where political actions (including occupations) can help achieve changes in land access regimes. The OTF action was successful in challenging cultural norms about property and achieving access, partly due to the occupation having foregrounded multiple appealing narratives that invited participation and wider support. These narratives included agroecology versus biotechnologies; community/public access versus privatization; participatory versus bureaucratic governance structure; and green space/food production versus urban development. The article tests the use of the ‘land sovereignty’ frame in expanding food sovereignty's land politics, to encompass land contestation contexts globally and deal with the particular conditions surrounding lands. The case indicates that land occupations in the North are potentially useful—but uncertain, and very context-dependent—tactics to promote land and food sovereignty.     

Gated Communities in the United States: From Case Studies to Systematic Evidence

Scholarly research about gated communities is a recently established field of study, because the significant proliferation of these communities has occurred in the last couple of decades. In this article, I argue that the seminal work of Blakely and Snyder (1997, Fortress America: Gated communities in the United States. Washington, D.C.: Brookings Institution Press.) gave the first impetus and the initial research directions in gated communities’ study. The subsequent research established it as a true interdisciplinary urban field and produced important knowledge across several different academic disciplines: sociology, political science, anthropology, urban policy and planning, geography, and legal studies. The article discusses this first phase of theoretical and empirical work, based mostly on qualitative and secondary data sources. A new methodological shift is proposed, which should determine the second phase of research based on hypotheses testing and collection of systematic empirical evidence. Such evidence is essential to understand the wider impact of gated communities on larger urban areas and society as a whole.     

Three categories of urban green areas and the effect of their different management on the communities of ants,spiders and harvestmen

Urban green areas have become an important tool for biodiversity conservation in cities. However, land use and the different management practices applied to these areas determine their effectiveness as biodiversity refuges within cities. In our study, we compare the biodiversity of three bioindicator groups of arthropods (ants, spiders and harvestmen) found in eleven urban green sites in Warsaw (Poland). The studied sites represent three categories of management: botanical gardens, public parks and urban woodlands. Our aim was to determine the effect of the type of management (as urban green categories) on arthropod communities in urban areas.

     

Urbanization impacts on land snail community composition

Urbanization has tremendous impacts on most native species. This is especially true in land snails, which are surprisingly understudied organisms. Due to their low mobility and dispersal potential, land snails are valuable indicators of ecosystem disturbance. For this study, land snails were collected in 54 city parks along an urban gradient to understand impacts of urbanization on snail communities. Sampled parks include small extensively landscaped downtown parks, neighborhood and community parks, district parks, and large nature parks, each with variable vegetation, soil characteristics, disturbance regimes, and human activities. Sampling recovered 12,153 individual snails, representing 20 families, 43 genera, and 95 species. Seven new Tennessee state and 87 new county occurrences were recorded. Five non-native and one extra-limital non-native species were found, four of which are new Tennessee state records. Results show that urbanization greatly alters land snail community structure. Nature and district parks have significantly greater species richness, species diversity and species evenness than community, neighborhood, and downtown parks. Degradation of parks, distance from the park to the commercial city center and percent of coarse woody debris accounted for most of the variation between park types. Non-metric multidimensional scaling and pairwise Jaccard indices indicate that downtown snail communities are more similar whereas snail communities in nature parks are more distinct. This suggests that urbanization promotes homogenization among land snail communities. We also show that this homogenization is thus far driven mainly by synanthropic, broadly adapted native species rather than non-native snail species.     

Individuals and Communities: the Importance of Neighbors Volunteering

In this analysis, I examine the effects of community-level volunteering on an individual’s choices regarding time – whether to work and whether to volunteer. In order to better explain the decision to volunteer, a classic pure public goods structure is contrasted with a less restrictive impure public goods model that admits other possible private motivations. The results of this study undermine the neoclassical notion that volunteering can be understood solely as a pure public good that is provided less when others are seen to be contributing. In fact, individuals are found to be more, not less, likely to volunteer when others in their communities do so. An innovative instrumental variables strategy is used to account for reflection bias and the possible endogeneity caused by selective sorting of individuals into neighborhoods, which allows for a causal interpretation of these results. Employment regressions provide preliminary evidence that average volunteering relates, to some extent, with the decision of whether to participate in the labor force. Variations in the effect of average volunteering across age and gender are also explored. The present work is unique by virtue of its use of a large and representative dataset, along with rigorous statistical testing. I use United States Census 2000 Summary File 3 and Current Population Survey (CPS) 2004–2007 September Supplement file data and control for various individual and community-level characteristics.     

Private Prisons in Public Discourse: Measuring Moral Legitimacy

New policies require legitimacy to survive. Prison privatization represents a policy challenged by initial perceptions of illegitimacy. In the 1980s, governments began to allow private firms to run correctional facilities, shifting an inherently coercive, traditionally governmental function—incarceration—to the private sector. With data from 706 articles in four major American newspapers spanning 24 years, this research uses Freudenburg and Alario’s concept of diversionary reframing to measure and track the moral legitimacy of prison privatization across time and place. Findings suggest that initially high levels of moral legitimacy facilitated some states’ adoption of private prisons, while initially low levels of moral legitimacy stunted the growth of privatization in other states. This study presents a novel way of measuring moral legitimacy, demonstrates how the concept may be used to help explain controversial public policy changes, and documents the cultural content of private prison debates in the United States.     

Suburban wildlife: Lessons,challenges, and opportunities

The United States, as well as most developed and many developing nations worldwide, is becoming increasingly urban and suburban.Although urban, suburban, and commercial development account for less than one percent to just over 20% of land use among states, 50–90% of the residents of those states can be classified as urban or suburban dwellers. The population of the U.S. as a whole has risen from being > 95% rural in the 1790s to about 80% urban-suburban today. With these changes in land use and demographic patterns come changes in values and attitudes; many urbanites and suburbanites view wildlife and nature differently than rural residents. These are among the challenges faced by wildlife biologists and natural resource managers in a rapidly urbanizing world. In 2003, we convened a symposium to discuss issues related to suburban wildlife. The papers presented in this special issue of Urban Ecosystems address the lessons learned from the early and recently rapidly expanding literature, the challenges we face today, and the opportunities that can help deal with what is one of the biggest challenges to conservation in a modernizing world.     

Out of the Limelight: Discredited Communities and Informal Communication on the Internet

In this article we will suggest that print and related traditional media have been used more successfully in constituting a public sphere than in supporting more private and localized forms of community building (Habermas 1989; Stone 1991). The costs and control of print media, in addition to the stability of the content, have reduced the applicability of these media to the improvisatory and quotidian social processes that groups use to help keep themselves cohesive. In contrast, computer-based interactions have been and are being used extensively to support many of the informal interactions and related activities necessary to communities, giving members new tools for negotiating and rehearsing public forms of group life (Jones 1995). We hope to show how the public aspirations and problems of social groups shape their encounters with computers and encourage them to use computer interaction to manage their public representations.     

Une privatisation inédite de la norme : le cas de la politique comptable européenne

EU member states have, for a long time, been harmonizing their accounting rules in order to facilitate comparisons among countries. A new regulation in 2002 has suddenly sped up this process. Under it, companies quoted in the stock exchange are, since 2005, required to comply with the standards set by the International Accounting Standards Board (IASB), a private body without any public mandate. After trying to harmonize its members’ standards, the EU’s decision to resort to private subcontracting is even more puzzling given the Union’s lack of any statutory control over the IASB. In this impressive case of the privatization of a regulatory process, attention is focused on the incorporation of IASB standards in EU law and on the structure and governance of this board. This transfer of power is much broader than usual forms of delegation to the private sector. Although several reasons underlie this relinquishment of public authority, the primary one lies within the EU itself.     

街道办事处改革与城市社区建设

改革开放以来,中国城市基层治理结构经历了以“单位制”为主转向以“街居制”为主的制度变迁。由于“街居制”在运作中面临一些深层矛盾,街道办事处改革的呼声一直很高。推进城市治理结构扁平化,有必要撤销街道办事处,由区政府直接指导社区建设,实行“二级政府、二级管理”体制。撤销街道办事处是一项系统工程,它有待于推进大部门体制、调整行政区划、培育非营利组织、发展公私合作关系等配套改革相支持。     

Differences between Cohousing and Gated Communities. A Literature Review

On the basis of the literature (produced mainly by sociologists, architects, and geographers) about gated and cohousing communities, this work analyzes how these communities differ from each other. The analysis suggests that cohousing and gated communities are different in the nature of relationships between residents and in the reasons why they arise, even if there are some points of similarity. The risk of a degeneration of cohousing in the gated type is linked in particular with a complete transformation of the grass‐roots model (typical of cohousing) to the top‐down speculative scheme (typical of gated communities).     

关于建立上海郊区差别化管理体制机制研究

建立上海郊区差别化管理体制机制的总体思路是:以主体功能区划分为基础,根据各区(县)不同的主体功能和开发任务,实施差别化政策;按照"二级市"的要求,简政放权,增强郊区自主发展权和统筹协调权;适度调整市、区财政分配体制,使郊区各区(县)事权与财权相匹配;建立和完善财政转移支付、土地利用激励、财政激励、生态发展激励和绩效考核五大机制,促进郊区差别化管理,增强郊区统筹协调发展的能力;实施"强镇扩权",创新郊区基层管理体制机制,增强郊区发展活力。上海建立郊区差别化管理体制机制,还需适当调整郊区城市建设标准、制定全市统一的公共服务资源配置和设施建设标准、增加郊区人口导入区城市管理和公共服务资源配置、规范简政放权的工作机制。     

A Comparison of Public and Charter School Board Governance in Three States

In this article we compare the governance behaviors and preferences of nonprofit charter school board members with traditional elected public school board members in Michigan, Minnesota, and Wisconsin. Using originally collected survey data, we find that nonprofit charter school board members are less likely to place emphasis on relations with the public, engage in conflict, be ideologically diverse, and perceive the executive as responsible for key governance tasks than traditionally elected public school board members. The findings provide new information for policymakers weighing the potential benefits of education privatization through the use of nonprofit charter schools against the potential loss of democratic board accountability.