Factors Influencing Establishment and Post-Establishment Residential Yard Tree Survivorship in Worcester, Massachusetts

Background Urban tree planting programs seek to maintain high levels of planted tree survivorship, as ecosystem services are maximized when trees are fully grown. This study examines survivorship for a cohort planted on residential properties by the Massachusetts Department of Conservation and Recreation (MA DCR) 2010 to 2012 in the city of Worcester, Massachusetts, USA. Methods Field surveys in 2014 to 2016 and 2023 were conducted to record tree survivorship status. Conditional inference trees were used to highlight potential site-level socioeconomic and biophysical drivers of tree survivorship, and logistic regression was used to determine the significance and impact of predictor variables. Results Overall survivorship over 12 years was 67% with a 96.8% annual survivorship rate (3.2% annual mortality rate). Annual survivorship in the establishment phase was 94.9%, while annual survivorship in the post-establishment phase was 97.7%. Results indicate that planting fewer number of trees on any property increases survivorship in the establishment phase, along with planting closer to buildings. In the post-establishment phase, distance from buildings was found to be important, but not significantly related to survivorship. Trees planted on properties with buildings built before 1930 have 1% to 2% higher annual survivorship rates in both the establishment and post-establishment phases. Conclusion Tree survivorship is comparable in this case to subsequent MA DCR tree planting programs and on par with similar studies reported in the literature. This work is unique among the literature for comparing establishment and post-establishment tree mortality; additional research could uncover how site- and species-level factors impact urban tree survivorship across multiple time periods.