Street trees exist within the blurred private-public space of the right-of-way and represent a highly managed landscape feature of urban socioecological systems. Although they are an important part of the urban forest landscape and provide valuable ecosystem services, the biophysical characteristics of the right-of-way and actions of human and non-human management agents have resulted in an uneven spatial distribution of street trees within many cities. There remains a knowledge gap in our understanding of how the social, built and bioecological interactions in the public right-of-way impact urban environmental change.
Doctoral student Shawn Landry under the guidance of Professor Jayajit Chakraborty in the Department of Geography at the University of South Florida will investigate the socioecological determinants of street tree distributions in urban residential neighborhoods in order to understand how household decisions and multi-scalar management agents shape urban forest change and the environment within the public-private space of the right-of-way. The research addresses three primary questions: Are recent changes to the spatial distribution of street trees explained by socio-demographic household and neighborhood characteristics? Which management agents are the strongest predictors of recent changes to street tree distributions and how does the contribution of these agents vary in relationship to socioecological patterns within a city? To what extent are household street tree management decisions related to the built and bioecological material characteristics of the public right-of-way? Multi-method empirical analyses will be conducted in a study area in and around Tampa, Florida, that includes single-family residential areas characteristic of a typical Sunbelt city. Urban remote sensing and land cover change analysis, combined with geospatial analytical techniques will be used to examine broader socio-demographic patterns associated with recent changes to street tree distributions. Household survey and semi-structured interview techniques combined with assessment of biophysical growing conditions will be used to examine the relative contribution to street tree distributions by specific agents and the socio-spatial determinants of household public right-of-way landscape decisions. This study will extend a research framework designed to capture the complexity of human ecosystems to reveal poorly understood aspects of urban forest change, such as how historical legacies affect adaptive management options associated with the right-of-way.
This research project synthesizes theory and methods from urban forestry, spatial sciences, environmental equity, and urban ecology to contribute new insights on environmental change associated with spaces characterized by complex social, built, and bioecological interactions. The findings from this study will inform and guide urban environmental management and policy decisions associated with the public-private space of the right-of-way. Research results will be presented in formats useful to local and national urban forest practitioners and through outreach efforts such as presentations and symposia with residents, neighborhood associations, elected officials and public agencies in the local municipalities. Through these channels, this project will increase knowledge and understanding of factors influencing urban forest sustainability and broadly extend societal impacts beyond the academic community.
Street trees exist within the blurred private-public space of the right-of-way. They are an important part of the urban forest that can provide direct and indirect benefits to social and ecological sustainability in cities. Temporal and spatial interactions between human and non-human management agents determine the distribution and health of street tree populations in urban areas. In many cities, there is an uneven spatial distribution of street trees, such that the benefits and/or costs associated with trees are unequally shared by urban residents. There remains a knowledge gap in our understanding of how the social, built and bioecological interactions in the public right-of-way impact urban environmental change. This research examined the determinants of street tree distributions in urban residential neighborhoods in order to understand how household decisions and human and non-human management agents shape urban forest change and the environment within the public-private space of the right-of-way. The research was guided by three primary questions: (1) Are recent changes to the spatial distribution of street trees influenced by socio-demographic household and neighborhood characteristics? (2) Which management agents are the strongest predictors of recent changes to street tree distributions and does the contribution of these agents vary in relationship to social-ecological patterns within a city? (3) To what extent are household street tree management decisions related to the built and bioecological material characteristics of the public right-of-way? These questions were investigated in a case study that examined street tree management and public right-of-way (PROW) canopy change associated with single-family residential areas in and near the City of Tampa, Florida. The methodological approach employed both quantitative and qualitative methods. Urban remote sensing and spatial analytical techniques were used to examine the geographic association between patterns of street tree change and socio-demographic characteristics. Household survey techniques were utilized to examine the determinants of street tree management; specifically planting, removal, and trimming. Interviews with key informants familiar with urban forest management provided additional insights to complement the location specific knowledge of household survey respondents. Street tree change was examined for the period of 2003 to 2006, and information about household management actions also included recent years (i.e., 2009-2011). A citywide pattern of street tree increases was disproportionately distributed with respect to socioeconomic status; with greater increases in affluent neighborhoods. Patterns of change within local portions of the study area revealed significant and spatially variable relationships with socioeconomic status, as well as race/ethnicity variables and indicators of lifestyle differences. The findings suggest that the citywide pattern of change associated with socioeconomic status may perpetuate an inequitable outcome in the distribution of street trees at the expense of less affluent neighborhoods. The local patterns of change indicate that the processes driving street tree distributions may also reflect differences in attitudes toward trees. Street tree increases were more likely in areas where tree trimming had been reported and where property market values were greater, but less likely in PROW segments with overhead power lines. Households, public agencies and builders, but not neighborhoods, were the primary human street tree management agents. Past and ongoing land development and redevelopment decisions, including the configuration of PROW infrastructures, may be one of the most important factors affecting patterns of street tree change. Landscape decisions and practices influenced by household and neighborhood group dynamics also appear to be important factors affecting street tree change. Damages caused by storm event and differences in tree species lifecycle characteristics represent important non-human agents of street tree change. The findings indicated that public agencies are not the only managers of street trees and household tree management does not stop at the boundary of private property. There was no evidence of a relationship between household management actions and the configuration of the PROW. However, there was a relationship between the presence of either power lines or sidewalks and household survey responses about who should bear responsibility for street tree management and the liability associated with damages caused by street trees. Household respondents expressed an increased sense of personal responsibility for street tree management when a sidewalk was in front of their home. This research addressed an important gap in our understanding about the factors driving street tree change. Planting, removal, and trimming of street trees in Tampa is a shared responsibility with complex spatial patterns and multi-scalar drivers. An important conclusion is that the sustainability of street tree populations within the urban forest will require urban planners and managers to better understand how these management agents cooperate if they are to promote healthy, safe and beneficial street tree populations as a part of the urban forest.
