Urban tree survival and stewardship in a state-managed planting initiative: A case study in Holyoke, Massachusetts

摘要

Stewardship is essential for the survival of trees planted in challenging urban conditions and for reaching canopy cover goals and anticipated benefits. The governance structure of the stewardship network can dictate stewardship efficacy and ultimately, tree survival. While many planting initiatives are managed locally, the stewardship network and survival rates of a state-managed initiative are not commonly addressed in scholarly literature. The Greening the Gateway Cities Program (GGCP) in Massachusetts is planting thousands of trees in post-industrial cities around the state. We carried out a mixed-methods case study of 2014 to 2016 tree planting in Holyoke, a GGCP pilot city, to assess the factors that influence survival. Specifically, we interviewed program stakeholders and coupled that data with field monitoring of trees planted along streets and on commercial and institutional landscapes. A logistic regression model shows that trees stewarded by state foresters were approximately 5.18 times more likely to survive, and trees which were not impacted by a summer 2016 drought were approximately 2.80 times more likely to survive. However, the drought impact was muted for trees stewarded by the state, and species characteristics were not significantly related to survival. Importantly, stewardship and planting site type strongly overlapped, providing insight into links between tree survival and stewardship network. At program launch, local recipients and partners agreed to water newly planted trees. But interviews revealed that tree recipients had neither the time nor staffing to adequately care for their trees. The GGCP intended for the local municipal public works department to assume stewardship responsibility, but the latter was unable and/or unwilling to do so due to a lack of funding and misalignment of goals, leaving stewardship as the state's responsibility. Dedicated funding and staffing for maintenance is essential for strengthening stewardship networks and improving survival of large-scale urban tree plantings. Additionally, urban tree survival can be more strongly mediated by stewardship actors than some biophysical factors.