New York City Urban Field Station

ULTRA-Ex: Understanding the Dynamic Connections among Stewardship, Land Cover, and Ecosystem Services in New York City's Urban Forest

[photo:] A NYC Parks intern measuring tree height with a clinometer.  Photo by Brady Simmons.How have efforts to re-green public and private urban lands in New York City affected ecosystem services (like stormwater management and air pollution removal), the engagement of civic stewards, and the capacity of the system to support biological communities? This project integrates recent advances within the fields of the natural and social sciences to advance our understanding of urban social and ecological systems. The data, findings, and activities from this study will contribute to our long-term understanding of the dynamic connections among stewardship, land cover, and ecosystem services in New York City’s urban forest. In addition, it will directly inform the management of natural resources in the City.


ULTRA-Ex stands for Urban Long-Term Research Area Exploratory projects. The National Science Foundation’s ULTRA-Ex program provided funding to 16 cities to build interdisciplinary research teams and develop long-term research agendas that focus on both social and environmental issues.

Long-term restoration in the Bronx, NY

Givans Creek Woods is an abandoned construction fill site where non-native the invasive plant mugwort (Artemisia vulgaris L.) has completely taken over. In 1999, an area of the woods was re-planted with a variety of tree species and soil additives in an attempt to create a native forest canopy that would shade out the invasive mugwort. The objectives of this study are to identify the best species for restoring degraded urban sites and to determine whether soil amendments are necessary to create a closed-canopy native forest.


Pelham Bay Park is New York City’s largest city park and has had a diverse land use history. From 1992 to 1995, one area of the park was chemically and mechanically cleared of all non-native vegetation and replanted with native trees and shrubs. This study compares sites with no restoration or management (control) to areas that were cleared and planted, with or without subsequent maintenance. Our objective is to determine whether these restoration efforts resulted in a more native and diverse ecosystem.

Environmental stewardship

Although recent academic and policy studies have focused on the increasingly wide range of organizations working as stewards to conserve, manage, monitor, advocate for, or educate the public about the local environment, it remains unclear how individual citizens get involved in local stewardship initiatives. Such knowledge is needed by professionals working to manage environmental stewardship programs and by anyone seeking to understand how the human infrastructure of environmental stewardship is established, maintained, and improved. NRS researchers contributed to t wo white papers that explore these issues based on a random sample of volunteer stewards who participated in MillionTreesNYC spring planting events in parks throughout New York City:

Other research focuses on the network dynamics of stewardship organizations citywide. Building on a survey of New York City stewardship groups (STEW-MAP), interviews with the most connected “bridge” organizations revealed a decentralized and polycentric civic-to-civic network with a flexible and multi-scaled capacity for urban ecosystem management.

Vegetation change

Aerial photographs and satellite images were used together with field observations to analyze changes in New York City’s urban forest over time. The resulting map uses color to display urban vegetation change from 1990-2010. This information is being used to summarize vegetation change by neighborhood across New York City.

Urban environmental stewardship and changes in vegetative cover in New York City Neighborhoods (2000-2010)

Through an interdisciplinary analysis of place-specific social and ecological data, this study explores connections between vegetation change and urban environmental stewardship in New York City neighborhoods. Vegetation change maps were overlaid with the self- reported physical boundaries of NYC stewardship groups in order to understand the influence of local community action on urban ecosystem dynamics. We are also examining the influence of development on neighborhood greening and stewardship.