Working Together to Inventory Philadelphia’s Trees

American cities are filled with trees. Often referred to as the urban forest, these trees line our streets, improve our air and water quality, and enhance our neighborhoods. Maintaining and caring for the trees is both a crucial and time consuming process. When municipal departments and non-profit or community groups organize management tasks, a current and complete inventory of street trees can be a valuable tool to assist with scheduling planting and tending efforts. Unfortunately, such inventories are resource intensive and can be difficult for organizations to conduct on a regular basis.

With these issues in mind, Azavea, a geospatial software design and development firm based in Philadelphia, took on the challenge of designing a web-based solution that would make the tree inventory process easier and more affordable for urban communities nationwide.  

.   Funded by a grant from the USDA National Institute of Food and Agriculture Small Business Innovation Research Program (Grant Number 2010-33610-20937), Azavea partnered with the Pennsylvania Horticultural Society, Philadelphia Parks & Recreation, the Delaware Valley Regional Planning Commission, and other local partners to create PhillyTreeMap.org, a web application that enables the general public to collaborate with local government and non-profit agencies to map trees in the 13-county, 3-state region around Philadelphia.

PhillyTreeMap.org contains information on over 177,000 trees. The trees can be searched by location, species, diameter, date planted, and other criteria. Search results are visible as icons on a map, and users can click the icon to view species, height, diameter, and other detailed information about the tree.

While data from local arboreal organizations is available in the system, public users are encouraged to update the existing information or add new trees in order to create a more up to date inventory. With a free account, users can easily edit details such as the species or location of a tree, upload images of trees, or add new trees to PhillyTreeMap. Changes are immediately visible, but a review feature also enables administrators to look for inaccurate or unsuitable changes.

To demonstrate the importance of trees to our communities, PhillyTreeMap also displays estimates of the ecosystem impacts of trees on air quality, carbon sequestration, and stormwater interception. Calculated using iTree, a system developed by the USDA Forest Service, and the species and diameter of the trees, the statistics provide a clear picture of the economic and environmental benefits of trees.

Public citizens are vitally important to the work of PhillyTreeMap and similar collaborative tree inventory projects. By adding information about local trees, members of the public assist in creating a comprehensive database of the urban forest and its myriad economic and ecological benefits. As the project grows, local horticultural organizations hope to include information about the site in their tree tending classes as a way to reach out to more individuals and increase the information available in PhillyTreeMap.

PhillyTreeMap was built on open source code contributed by Urban Ecos and Umbrella Consulting for the Urban Forest Map project in San Francisco. In July 2011, Azavea released the source code as an open source offering called OpenTreeMap to enable individuals to build similar projects in other municipalities. Azavea plans to add new features to the OpenTreeMap software, including mobile and tablet versions, over the next year.