Society for Conservation Biology

SCB Advances Policy Tools to Protect Urban Forests
By Christine Real de Azua

Protection of urban and suburban forests in rapidly urbanizing environments is one of the next frontiers in forest protection, climate management, and the fight to conserve biological diversity. The relentless loss of mature canopy and natural green space in urban and urbanizing areas risks undermining sustainability even in jurisdictions that are attempting to implement “smart growth” policies.

The Urban Forests project of the Society for Conservation Biology in 2013 aligned local action to protect urban forests through new incentives in the Montgomery County, Maryland zoning code and other laws with a push to properly value natural capital and its many services in measures of economic performance.

At the 2013 International Congress for Conservation Biology (ICCB) in Baltimore, Maryland, a symposium on ecosystem valuation tools and measures of performance discussed the limitations of the existing System of National Accounts from which Gross Domestic Product (GDP) is derived, and potential applications for new measures such as Maryland’s Genuine Progress Indicator (GPI). Maryland is the first state to have officially established a GPI. The panel also looked at current advances in ecosystem valuation tools and their use in cost-benefit analysis of proposed actions by federal agencies such as the Bureau of Land Management of the US Department of Interior.

At the local level, SCB's North America Section and its Urban Forests project commented on the Montgomery County, Maryland’s “Rewrite”—the first revision to the County's zoning code in 35 years – to propose mechanisms to both value and protect urban forests. These recommendations are replicable in other local jurisdictions.

Montgomery County, Maryland, also offers a "ground zero" test case of how endangered species protection, and the solutions for their survival and recovery, can overlap with protection of urban forests and their many services, including stormwater management and climate regulation.  In this case, the highly imperiled species are amphipods, whose decline has paralleled the decline in freshwater springs and in forest cover in the suburban Maryland and Washington DC metropolitan area.   

This test case is coming to a head because of the cumulative impacts of accelerated residential and commercial development in suburban Maryland and the direct and cumulative impacts from the proposed Purple Line, a light-rail transit line that would originate in downtown Bethesda and cause the felling of 47 acres of urban forest along its path, mostly in its western section from Bethesda to Silver Spring--through sensitive amphipod habitat.  This loss of tree canopy and green space would reduce ecosystem services such as stormwater management, replenishment of groundwater and seeps, air and water pollution filtering services, wind and temperature regulation, and climate resilience. These losses are compounded by the losses of green space occurring on private lots--a problem for which the Urban Forests has proposed solutions through its comments on the Montgomery County Zoning Code.

Two analyses prepared by biologists with expertise on these amphipod species, David Culver, Ph.D. and David Berg, Ph.D., describe the amphipods and the ecosystems for which they serve as indicators, the threats to these species and ecosystems including immediate threat triggered by the Purple Line as proposed, and recommendations for species' recovery. The Project identified Dr. Berg initially through the SCB Expertise Database where he is listed for his expertise in aquatic invertebrates. Click here for the analysis by Dr. David Berg and here for the analysis by Dr. David Culver. The memos of Dr. Culver and Berg will support steps for preserving those spaces and their many services, from ensuring compliance with existing law to helping to shape options for improving existing zoning, land use plans and other tools.  

The work of the Urban Forest Project overall will enable planners, decision-makers, and others to apply to specific areas such as Montgomery County, the tools and methods now available from agencies, think tanks, and other sources that highlight, measure and evaluate the many benefits of green space and natural systems.