The U.S. housing market is in such decline that foreclosures have even reached some of the wealthiest, most exclusive neighborhoods in the country, places that are normally immune to real estate shifts. In a remarkable turn-around, conservation groups suddenly have so much buying power that more U.S. land was protected than developed in 2007.

Here’s how it’s happening. As homeowners try to ride out the burst real estate bubble in their current homes rather than upgrade or move, and scores of Americans become renters after losing their homes in foreclosure, developers are stuck with large, prime tracts of land they can’t build on since no one will buy.

As a result, they sell the real estate at reduced prices, and it’s usually in locations near urban centers. Conservation groups like the Trust for Public Land and the Nature Conservancy are snapping up the tracts and turning them into parks, nature preserves and green spaces:

So far, the land sales are small and barely dent development -- or hurt local governments' property-tax collections. But they are helping conservation groups raise new funds and increase their buying power. Big creditors and financially stressed developers also are viewing these groups as a lifesaver.

In Portland, Ore., a developer that had approval to build 65 homes on a 27-acre parcel agreed in February to sell it for $4 million, a 20% discount to the land's appraised value before the housing market softened. In Groton, Mass., the Trust last July paid $19.4 million to preserve a 360-acre farm that was owned by a developer who abandoned plans to build 130 homes as housing there also slumped. The Portland land will be added to an existing park; Groton will receive the land for open space. – Wall Street Journal

Increasing public lands and expanding natural, open spaces comprise just about the only positive news in an increasingly bleak housing picture. The news is especially timely, too, as Americans have concentrated more on conservation efforts in recent years:

Public support for open space has been on the rise. Since 2000, voters have approved $30 billion in bond measures for conservation, Wentworth says. A change in the tax code last year sharply raised the incentive for landowners to donate development rights on their property and contributed to a record year.

In 2007, conservation groups preserved more than 2 million acres — more land than was developed in the USA. The real estate crisis may result in another banner year for conservationists, especially if Congress renews the tax break for landowners. – USA Today

The Wall Street Journal reports some critics’ fears over urban sprawl and higher land prices as real estate near cities is preserved rather than developed into living spaces, but I can’t help thinking about the positive long-term implications on development.

Increasing urban green spaces offers benefits, health and otherwise, beyond the obvious and immediate recreational value for city dwellers. The park movement within Chicago neighborhoods is a good example. Activists and community advocates there are successfully maneuvering a major expansion of urban Haas Park and the creation of Bloomingdale Trail to link diverse parks and neighborhoods throughout the city. Projects like these increase valuable fitness and recreation options, and that translates to good long-term health:

Parks are essential to the health of individuals and communities. They offer recreation and renewal, promote exercise, reduce crime, revitalize neighborhoods, protect the environment, and bring communities together. Children without access to parks suffer from higher levels of obesity, diabetes, asthma, anxiety, and depression. – The Trust for Public Land

Families like mine settle in suburbs in part because of easy access to parks and preserves. As land conservation deals like these generate more green spaces into culturally rich cities, urban families may just end up with the best of both worlds.