City-Wide Assessment of New York City's Forests

Cities across the globe are increasingly focused on increasing tree cover as a way to improve the urban environment. Because of the well-known connection between nonnative invasive species and urbanized areas, there is an expectation that urban forests are degraded. Yet other studies have shown high biodiversity in urban forested natural areas. In New York City, the Natural Areas Conservancy undertook a city-wide assessment of forested natural areas to determine the species composition found across New York City’s forests, and whether they were primarily native or nonnative dominated. Then, the team compared New York City's forests to rural forests in New York state, both in terms of stand structure and forest type. Finally, they analyzed how overstory stand structure was related to the understory species composition. 

In a nutshell, this resource offers:

• An analysis of the vegetation found in 1,124 forested plots in New York City, finding native species across 84% of total canopy, but 53% of native species in the understory.
• Findings that refute previous conceptions of New York City's urban forest as co-dominated by nonnative trees.
• An approach to assessing forest quality and quantity in a city.

How to use this resource:

• Observational evidence to support the removal of nonnative invasive species and woody vines to favor native forest regeneration and regrowth.
• A methodology to assess the composition, structure, and condition of forest in an urban area.
• A citation that justifies the need for forest assessment and management in cities.

Author: Clara Pregitzer, Sarah Charlop-Poweres, Silvia Bibbo, Helen Forgione, Bram Gunther, Richard Hallett, Mark Bradford

Date published: 2018

Point of contact: Clara Pregitzer, Deputy Director of Conservation Science, Natural Areas Conservancy, clara.pregitzer@naturalareasnyc.org 

Citation: Pregitzer, C. C., Charlop-Powers, S., Bibbo, S., Forgione, H. M., Gunther, B., Hallett, R. A., Bradford, M. A. 2018. A city-scale assessment reveals that native forest types and overstory species dominate New York City forests. Ecological Applications. pp 1-11.

Resource is available online here.