TreesCount! training

At TreesCount! 2015 orientation events, NYC Parks staff and their partners met with volunteer citizen scientists to talk about how the ongoing census helps the City, how citizen scientists can participate in the data collection, and how the census methodology works in the field.

by Charles Cochran, Street Tree Census Coordinator and Ben Greer, TreesCount!2015 Assistant Coordinator, NYC Parks and Recreation
~Infographic by Peter Tiso and Annie Weinmayr
~Photos Courtesy of NYC Parks

TreesCount! 2015 is the third decadal inventory of NYC’s street trees. This is the first tree census to use volunteer citizen scientists to be the primary data collectors. Individuals who have mapped went through a full training process with NYC Parks Census staff, mapped in “events” with other volunteers or mapped independently. Community partners ranging from environmental non-profits, business improvement districts, youth groups and community boards have also played a key role in training and engaging volunteers to map their neighborhoods. Volunteers have mapped 200,000 trees, 30% of the city, since May 2015.

The street tree dataset will provide NYC Parks with information that can improve operational efficiency in the field, better allocate funds for high priority projects, and investigate the best management practices for urban trees. A complete census will allow us to assess trends in tree health, diversity, and growth. Research specific, pressing environmental questions like how the trees of New York City have responded to inundation from Hurricane Sandy. The data will also help dictate Central Forestry’s street tree planting program to better target areas in need.

Volunteer effort!

TreesCount! 2015 could not have been completed without an overwhelming volunteer effort. The Census event staff helped host 900 events in all five boroughs, engaging 2,286 volunteers.

This data will also hopefully engage and inform NYC’s volunteer tree steward community. The Parks Digital Media team in conjunction with the Stewardship Division has launched a beta version of the NYC Tree Map. This interactive tool allows tree stewards to adopt trees, record their tree care, locate trees in need and report problems. Please take a look and send our Digital Media any comments, suggestions, or praise!

Fordham students

College students at Fordham University in the Bronx pitch in and count. This group is emblematic of the large role students played in the volunteering mapping effort. TreesCount! 2015 had mappers from all educational levels participating through structured class involvement to individual volunteering efforts. One of our favorite student mappers had to complete three hours of volunteer work for school, but after he reached his quota, he loved it so much he mapped 25 more!

The TreesCount! 2015 dataset will also be distributed to the public through NYC Open Data law. The dissemination of the data will hopefully empower people to become active stewards of the urban forest and provide essential information to local non-profits to help with grant writing and labor and money allocation.

Parks staff

TreesCount! 2015 was primarily a volunteer effort, but there are a whole host of Park’s employees working hard in various functions to facilitate the completion of the census. Expert data collectors were deployed across the city to map difficult blocks and perform quality assessment of completed work. GIS specialists compile and organize raw data, and volunteer coordinators engaged and trained New Yorkers to map NYC’s urban forest.

Once the census is complete, the Parks department will calculate the ecological and financial benefits of each street tree and the tree population as a whole. Currently 80% of the city has been mapped. The Bronx, Manhattan, and Staten Island have been completely surveyed. 2,286 volunteer mappers have identified 132 tree species for a grand total of 531,695 trees being counted. The remaining 26,000 blocks are expected to be completed by early fall 2016.


Not many TreesCount! 2015 volunteers were under the age of 10, but those few  that did map received a crash course on urban environmental education. The children of New York City like any youth in the world are born with an innate curiosity and love for the environment but lack chances to interact and actively engage with it. The methodology of the census allowed any age group to get involved and play a helpful role.

The 2015 Street Tree Census used a spatially accurate method developed by TreeKIT to inventory trees. In contrast to previous census mapping methods, the TreesCount web app maps trees using geospatial imagery. The web app allows a citizen scientist to choose any block in the city, map the trees, and then upload the data in real time into the TreesCount! 2015 database. The streetscape infographic below outlines the procedure, step by step, of how a citizen scientist would map a typical block in New York City (for a higher resolution version, click here). For more information about TreesCount! 2015, please see the project’s website.

How Data is Collected