Natural regeneration in urban forests is limited by early-establishment dynamics: implications for management

Urban forested natural areas are valuable ecological and social resources, but long-term sustainability of these habitats is challenged by environmental and social factors associated with urban ecosystems. In this study, we compare urban and rural oak–hickory forest composition and structure and the capacity for natural regeneration in the New York metropolitan area. We found differences in recruitment dynamics between urban and rural forests that have implications for the sustainability of these forests and new management strategies. 

First, after controlling for forest community type, species composition in urban and rural sites was significantly different across multiple strata and within the seed bank. Species-specific capacity for natural regeneration was different in urban and rural sites, signaling the possibility of divergent successional trajectories. Second, while differences in species composition exist, both urban and rural sites were dominated by native species across all forest strata except for urban seed banks. Third, despite finding significantly lower average annual seedling abundance in urban (1.9 seedlings/m2) compared to rural (7.1 seedlings/m2) sites, we observed greater density of saplings in urban forests, and no significant difference in stocking index between sites. 

These findings suggest that  early-establishment barriers to recruitment are greater in urban forest sites. However, once established, seedling transition into advance regeneration stages may not be different between site types, and advance regeneration may, in some cases, be more viable in urban forested natural areas. These results highlight functional differences between urban and rural forest recruitment dynamics that may impact on the future community composition of oak–hickory forests in the two landscape settings.

In a nutshell, this resource offers:

• A peer-reviewed scientific study that quantifies natural regeneration patterns in New York City's urban forested natural areas.
• Recommendations for managing natural regeneration in urban forested natural areas, based on the study findings.
• Descriptions of how urban forested natural areas are similar and different from rural forests.

How to use this resource:

• As a source or citation to justify the need to manage urban forested natural areas for long-term health and sustainability, specifically by using silviculture.

Author: Max R. Piana, Richard A. Hallett, Myla F. J. Aronson, Emily Conway, Steven N. Handel

Date published: 2021

Point of contact: Max R. Piana, max.r.l.piana@gmail.com 

Citation: Piana MR, Hallett RA, Aronson MFJ, et al. 2021. Natural regeneration in urban forests is limited by early-establishment dynamics: implications for management. Ecol Appl 31: e02255.

Resource is available online here.