International Herald Tribune: As a suburban environmentalist, Mike Tidwell, 45, of Takoma Park, Maryland, always felt like a walking contradiction. Though he had quit his job as a journalist to work for environmental nonprofit organizations, Tidwell viewed suburbs (his own hometown is just outside of Washington) as places built "to defy nature," he said, giving everyone "their own little kingdom of grass and space" – not to mention 3,000-square-foot, or 280-square-meter, houses, heated swimming …