Nearly 6,000 planning practitioners and scholars converged in Philadelphia last week for the 99th annual national conference of the American Planning Association (APA). A theme evident in many of the 300 seminars was how U.S. cities are grappling with what one presenter termed the “post-Federal” era: the current climate in which municipalities can no longer rely on federal monies but must instead secure philanthropic and corporate support to help resolve social and infrastructure problems.

Green space, many speakers agreed, is a critical asset that cities may use to their benefit. Environmental lawyer Robert Kennedy gave the conference’s keynote. He contended that only through planners’ individual commitments to embracing sustainability can the nation preserve its natural infrastructure—its parks, waterways, and woodlands—and counter the current lack of public investment in environmental policy. America’s green spaces, he added, are critical to sustaining the foundation of our nation’s global identity.