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Ecoroofs: for the birds?


Two weeks ago I attended an open house at the Audubon Society of Portland, a chance to meet and see up close the organization's educational birds, those injured or otherwise unable to survive in the wild now used to teach about habitat and conservation - such as Jack the Sparrowhawk, Julio the Great Horned Owl, Aristophanes the Raven, and Ruby the Turkey Vulture.

Some of these are not birds ever likely to be common to urban landscapes, even those with a massive forest inside city limits like Portland. Even so, it was such an inspiring site to see these magnificent birds up close that it got me wondering about efforts to re-introduce nature and wildlife into the city through ecoroofs, bioswales and greenspaces.

Portland has become a national leader for ecoroofs, particularly ones that are designed to capture stormwater. But what if the city's collection of green roofs could, once expanded, go a step further and actually become a functional habitat for birds and wildlife - part of a green infrastructure in the city? Ecoroofs do a lot for buildings themselves, insulating them better and reducing energy bills, besides capturing stormwater to prevent runoff. But it wouldn't take much for them to be bird magnets as well.

As it happens, March is being promoted as "Ecoroof Month" by the City of Portland, the Audubon Society of Portland, and the Urban Greenspaces Institute. Events will include "Ecoroof Portland," a free two-day event this Friday and Saturday (March 12-13), as well as an ecoroof tour of South Waterfront on March 27, lectures on March 30 and 31 by London ecoroof expert Dusty Gedge, and an ecoroof tour of downtown Portland on March 31.

As Bob Sallinger, conservation director for the Audubon Society of Portland notes in the organization's wonderfully titled newsletter, the  The Warbler, there are already 200 ecoroofs in Portland, and the city has set a goal of increasing vegetated rooftops to cover at least 39 acres by 2013. An incentive program initiated by the city in 2009 provides property owners with up to $5 per square foot to install ecoroofs. According to the City's ecoroof website Buildings can also receive bonus FAR (floor area ratio) based on three ranges of ecoroof coverage in relation to the building’s footprint: 10-30%, 30-60% and 60% or greater earns one, two and three square feet of additional floor area per square foot of ecoroof respectively.

Chicago is the only American city with more ecoroof area then Portland, with 534,000 square feet of ecoroof space compared to the Rose City's 423,000 as of 2009. But how are we doing compared to Europe, where ecoroof building leads the world and dates to the 1970s? We've got a lot of catching up to do.

For example, the metro area in Stuttgart, Germany, home of the exquisite Mercedes-Benz brand, has 10.7 million square feet of estimated ecoroof area. Dusseldorf, Germany's overall metro area has 7.86 million square feet. Basel, Switzerland - just the city, not its metro area - had 7.53 million square feet of ecoroof area as of 2007. London has 5.38 million, not including its suburbs and exurbs.

"Portland is particularly well positioned to learn from the European experience with ecoroofs and the emerging trend of biodiverse ecoroofs," writes Jim Labbe of the Audubon Society, also in The Warbler. "Efforts in the United Kingdom, Germany and Switzerland clearly indicate an ecoroof building boom is possible with the right public policies in place. These include adequate incentives and regulation to strongly encourage or require ecoroofs on new development where technically feasible. However we also need local research to help improve designs of biodiverse ecoroofs adapted to our unique climate, flora and fauna."

"By investing in and expanding biodiverse ecoroofs in Portland, we can dramatically expand urban habitat diversity, enrich our local and neotropical bird populations, and help keep nature nearby in our densest neighborhoods."

In 2006 I wrote an article for Metropolis magazine about Tanner Springs Park and its design by German landscape architect Herbert Dreiseitl, which was indicative of an an emerging philosophy regarding wild-life protection in a high-density urban setting. "Instead of just setting aside one or two larger parcels on the outskirts of the city, Portland planners favor also introducing small pockets of nature throughout," I wrote back then. “We’ve done a lousy job of protecting nature in the city until very recently,” added Mike Houck, urban naturalist for the Audubon Society of Portland and director of the nonprofit Urban Greenspaces Institute. “This is a new phenomenon.”

In seeking to become a sustainable capitol, can Portland also become an innovator for nature in the city? Sure, if the Europeans haven't beaten us there first. But Portland also boasts something these older European cities perhaps don't, or at least not in as much supply: enough space, and enough of a connection with the surrounding natural landscape, to enjoy a more substantial connection between city and nature. In that way, the urban growth boundary is as important as ecoroofs. But as with urban planning, it takes both macro and micro level design and implementation to make the unified whole work successfully - a unified plan for growth, and means to make it happen block by block, or in this case, roof by roof and park by park.

Photos:Brian Libby and Jaysonphoto via Flickr 

by Brian Libby, 2008­

Published with permission of Portland Architecture­­

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