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.
There are two purposes to the present study. Our methodological purpose is to develop and test a procedure and instrument for assessing crime- and fear-related features of the urban residential environment. We examine three classes of cues: symbols of social and physical disorder, territorial functioning, and architectural 'defensible space' features. Past research examining the physical environment correlates of fear of crime has relied almost exclusively on subjective perceptions of the environment rather than on independent and objective measures thereof. Our theoretical purpose is to test the 'disorder' thesis of Skogan, and Wilson and Kelling, that actual physical incivilities erode resident's confidence in their neighborhood and lead them to infer that serious local problems, unrelated to the physical environment, are serious. We conducted environmental assessments and resident interviews (n = 412) on 50 blocks in 50 Baltimore neighborhoods. The assessments demonstrated high levels of inter-rater reliability and concurrent validity, controlling for social class. Regression analyses showed that physical incivilities were independently linked to perceptions of social and crime-related problems. The results show that reliable and valid assessment of crime- and fear-related environmental features can be conducted. They also support the central kernel of the Wilson and Kelling, and Skogan thesis, that the actual presence of disorder-related cues engender perceptions of social and crime problems.
