Mapping Philadelphia’s Urban Forest

We’ve sat under their shade, watched their leaves turn red and orange in the fall, and seen their limbs heavy with snow – but we’ve never had a reliable database of street tree locations. After an exhaustive virtual assessment, Philadelphia Parks and Recreation (PPR) has provided community members with this big picture by releasing a map and an open dataset of all street trees.

 

Newly Released Data at a Glance:

  • PPR’s interactive tree inventory map.
  • Geospatial open dataset of tree points in Philadelphia which shows the exact location of the City’s 112,000 street trees.

 

Managing Street Trees More Efficiently

To compile this list of 112,000 street trees, PPR used CycloMedia – an online tool that provides georeferenced, high-definition street-views – in order to virtually explore an image of each street tree and identify its exact location. The availability of the ‘geolocation data’ (the latitude and longitude of where the tree is rooted) allows for precise mapping and better management of the tree inventory by PPR. The total number of street trees will change over time as trees are added and removed from the earth, or as PPR corrects any errors or omissions from the data capture.    

“PPR took advantage of a pilot project coordinated by the GIS Services Group to evaluate custom-capture street view imagery that integrates 100% with the City’s GIS. PPR did more than a ‘test drive.’ Their GIS staff realized the value of the imagery to their work immediately, and created a new and vital data layer at very little cost to the department or to residents. PPR’s project shows how City government can leverage new and existing technology together to more efficiently produce quality data that focuses our services and decisions,” said Mark Wheeler, Chief Geographic Information Officer for the City of Philadelphia.    

For many City departments, finding the most efficient, accurate and innovative way of providing services to residents is not just about saving money – it’s also pragmatic. Tree inventories in other cities have relied on staff and volunteers conducting on-foot canvassing of street trees. But Philadelphia, the fifth largest city in the US, measures out to 142 square miles – an area equivalent to 68,728 football fields. By using CycloMedia, PPR documented the precise location of every street tree  across the entire city in less than 5 months – an extraordinarily short amount of time given the size of the city.

This inventory now serves as a solid foundation for gathering and maintaining an accurate record of tree species type, size and maintenance needs by PPR. It will be used as the basis for work orders, long term management plans by PPR, and to help better quantify the economic and environmental benefits of street trees.

 

Tree Health is Community Health

Street trees offer numerous benefits beyond just some much-needed shade on a hot day. They make up an important part of our urban ecology. A healthy tree canopy improves and cleans the air we breath, aids in filtering our water, helps lower summer temperatures, reduces residential heating and cooling costs, increases the valuation of our homes, and generally contributes to community well-being.

Nora Dougherty, PPR’s Lead GIS Specialist, noted the potential of this data, “This inventory will help us better maintain street trees and prevent accidents and damage from fallen trees. It can also assist us in strategically planning where to plant more trees so that we achieve the City’s sustainability goal of 30% more tree canopy.”

Community organizations can use this data to identify the most-needed sites for beautification efforts. It can also direct PPR on where to focus limited resources in their TreePhilly program, which provides free trees to residents, particularly in areas lacking them.

Areas of poverty and low tree density are often plagued with high rates of crime and violence and, while these are complex issues, trees have been linked to improved quality of life and reduction in crime. A study released in June of 2012 showed a strong relationship between tree canopy and the reduction of robbery, burglary, theft and shootings – a 10% increase in tree canopy was associated with about a 12% decrease in crime.

 

Tools for Trees

This inventory is not the first of it’s kind in Philadelphia. Azavea, a local GIS software company, developed OpenTreeMap, a collaborative platform for engaged residents to document trees. This worldwide tool is an exciting and participatory community resource. But for managing local street trees, PPR needed a highly accurate inventory of location and tree characteristics on which to base work orders for maintaining and planting trees and removing those that were dead or dying. PPR’s systematic documentation of every street tree location will allow PPR arborists and contractors to leverage GIS to most efficiently route workers to sites, identify all trees within an area, and select for trees by variety or size.  

Engaged community members who want to contribute to documenting street trees can use PPR’s inventory in conjunction with OpenTreeMap, so that the tools compliment each other. PPR’s inventory can help overcome some of the inaccuracy or incompleteness that crowdsourcing tools may encounter and, as residents add new tree details to PhillyTreeMap, it automatically calculates overall economic benefits related to energy conservation, stormwater filtration, air quality improvement, and the removal of carbon dioxide.

For an in-depth review of PPR’s tree inventory process, check out PlanPhilly’s article, “Philly Mapped Street Trees for Better Maintenance.”

 

Keep in Touch!

There’s lots of ways to get involved. For information about City datasets and others, go to OpenDataPhilly.org. Visit this resources page for video tutorials and links to tools to help analyze data. Follow @PhilaGovData on Twitter to get alerts on future data releases, share how you plan to use open data with data@phila.gov, and join us on the public open data google forum.

 

Photo Caption: Photo of the Philadelphia skyline and trees, by camera_obscura, https://www.flickr.com/photos/musaeum/5103227204/, CC BY-NC 2.0.


Top