Greening the Void

The Knight Cities Challenge asks: What’s your best idea to make cities more successful? For team member Matt Langan, the prompt was different from that posed by the 2005 Urban Voids: Grounds for Change design competition, but the answer was the same: an Urban Arboretum.

Langan imagined large underutilized swaths of Philadelphia transformed into a working urban forest. Vacant lands would be reforested, simultaneously encouraging economic growth and generating a myriad of environmental benefits – cleaner air and water, heat-island reduction, and carbon sequestration. The urban voids in the City of Brotherly Love would be filled with greenery.

Urban Arboretum

Matthew Langan’s initial vision for an Urban Arboretum in Philadelphia. (Credit: Matt Langan)

Re-imagining vacant land in Philadelphia (and many Rust Belt cities) is nothing new. In areas where vacancy has long been an issue, neighborhoods have often used the wasted space for community gardens and recreation. In the Mill Creek neighborhood of West Philadelphia, Aspen Farms Community Garden has a history dating back to the 1980s. Solutions to vacancy have emerged more abundantly in recent years as many have seen these forgotten lots as opportunity grown out of necessity.

With the help of partner organizations, City Parks Association has spurred innovative thinking surrounding the issue in Philadelphia, launching the Urban Voids competition and the Grounds for Change: Activating Vacant Land website in 2010. Last month, Detroit Future City (DFC) released the “Field Guide to Working With Lots,” which highlights local examples and explores different design options with step-by-step instruction. In later posts, we’ll highlight this initiative and other exceptional examples in Philadelphia and other cities addressing vacancy.


A vacant lot in Philadelphia. The city has approximately 36,000 vacant properties, representing nearly 1,000 acres.

As a recent Knight Cities Challenge winner, City Parks Association is leading a cross discipline team to implement Urban Arboreta: transforming ground, which seeks to improve the social, ecological, and economic health of neighborhoods with high rates of vacancy. While quite literally “transforming ground” in the physical sense, the project will also have a strong community focus, with efforts to engage community members via accessible programs, educational opportunities, and job skills training in the nursery trade. The intent is to create a robust, self-sustaining operation that also benefits the ecological systems and human communities that surround it.

Our hope is that the Urban Arboreta model can be replicated across Philadelphia and elsewhere, perhaps even serving as the “New Green Space Model” for future cities. Please stay tuned for project updates and additional blog posts as we identify our project site and launch our design competition in the next couple months.