The importance of current and potential tree canopy on urban vacant lots for landscape connectivity

Recent studies have paid increasing attention to the ecological benefits of vacant land. However, there have not been holistic assessments of the importance of tree canopy on vacant land as a component of greenspace networks within cities, and the potential impact of developing vacant land on connectivity within these networks at the city scale. In this study, we use Hartford, CT, USA as a case study to evaluate the contribution of existing tree canopy on vacant lots to landscape connectivity and to assess how future vacant land development scenarios alter landscape connectivity at the city scale. This study leveraged morphological spatial pattern analysis and network analysis and found that vacant lots supported approximately 8% of core canopy area, 13% of corridors, and 12% of landscape connectivity value in the entire city landscape. In addition, we found that the factors including lot size, average distance to all cores, perimeter-area ratio, zoning, and percentage of tree canopy were the best predictors of the landscape connectivity values of individual vacant parcels through Random Forest. Furthermore, potential vacant land management scenarios with varying degrees of development, preservation, and greening were compared. An "Extreme Greening" scenario increased existing landscape connectivity by 16%, and an "Optimized Conservation and Development" scenario increased landscape connectivity by 3%, which could enhance the landscape network while still fulfilling the needs of redevelopment. This study illustrates the importance of considering landscape connectivity values of vacant land during the reuse process, and similar analysis could be applied in other cities to help incorporate existing ecological values during vacant land transformation decision-making.