Cities around the world are investing in urban forests as a form of green infrastructure. While significant resources are being dedicated to these projects, there is little research on urban forest dynamics and even less on woody plant recruitment and regeneration in urban forests. The few urban recruitment studies that have been done suggest that in urban settings and on degraded sites, recruitment can be one of the most limiting factors to reforestation. Working in partnership with the New York City Department of Parks and Recreation and the US Forest Service on experimental plots that were established as part of the MillionTreesNYC Initiative, we measure natural regeneration in 54 plots in a high-traffic urban park. Pre-planting treatments such as compost amendments increased the number of woody plant recruits but had a trade-off in terms of native vs. non-native regeneration. Interactions between pre-planting treatments also impacted the number of woody plant recruits by either increasing or decreasing woody plant recruitment depending on whether or not treatments were implemented independently or in combination with others. These findings have the potential to be implemented in future planting projects to encourage natural regeneration and steer species composition to achieve a healthy and sustainable urban forest in NYC and other cities worldwide.

Watch a 7-min presentation on the research by the fellow.