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The growing proportion of human populations living in urban areas, and consequent trends of increasing urban expansion and densification fuel a need to understand how urban form and land use affect environmental quality, including the availability of urban green spaces. Here we use Sheffield as a case study of city-wide relationships between urban green space extent, quality (vegetation cover and tree-cover), and gradients in urban form and topography. The total area of buildings and length of the road network are equally strong negative predictors of extent of green space, while the former predictor is amore important negative influence upon green space quality. Elevation positively influences extent of green space but negatively influences tree-cover. In contrast, slope of terrain positively influences green space quality and is the best predictor of tree-cover. Overall housing density is a more important negative predictor of extent of green space and tree-cover than the densities of individual housing types. Nevertheless, the latter are more important influences upon levels of vegetation cover. Threshold effects of densities of different housing types suggest opportunities for optimising green space quality, with implications for housing policy. Variation in ecological quality of green space may partly reflect different historical intensities of industrial activity.

To what extent does the density of the tree cover in a city relate to the amount of social capital among neighbors? To address this question, we linked social survey data (N = 361) from the Baltimore Ecosystem Study with socioeconomic, urban form, and green space data at the census block group level using a geographic information system. We found a systematically positive relationship between the density of urban tree canopy at the neighborhood block group level and the amount of social capital at the individual level (r = .241, p < .01). Multiple regression analyses showed that tree canopy added a 22.72% increase in explanatory power to the model for social capital. This research adds a new variable—neighborhood tree canopy—to the typologies of green space that affect human social connection. Trees are a relatively inexpensive and easy intervention to enhance the strength of social ties among neighbors.

‘Green infrastructure’ is a term used to describe systems of parks, greenways, open spaces and other natural landscape elements that provide community benefits. Although we have some understanding of how people use parks and developed greenways, little has been documented about use of the undesignated public and private spaces along green infrastructure features such as stream corridors. The purpose of this research was to examine characteristics that may influence people’s use of undesignated open spaces along the stream corridors that form the skeleton of many green infrastructure systems. Data were obtained from a Recreational Use Attainability Analysis (RUAA), an evaluation performed for the Texas Commission on Environmental Quality. The RUAA was conducted for 85 survey sites along 243 km (151 miles) of streams in Houston’s Buffalo Bayou watershed. Results indicate that the proximity of stream corridors to local residents, the level of pedestrian access available and tree cover were the best predictors of recreational use while the presence of water, fish or other wildlife were not significant predictors. Observations also indicated that urban and suburban stream corridors afford a variety of recreational and aesthetic values to residents. Implications for policy, planning and design of green infrastructure are discussed.