Home to an expanding light-rail system, a thriving bike culture, a citywide recycling program, and a large number of LEED-certified buildings, Portland, Oregon, has long been known for its green sensibility. So it seems fitting that a government building there may soon be sheathed in a 200-foot-high living wall that would be visible from miles away.The vegetated facade is part of a roughly $135 million overhaul planned for the Edith Green-Wendell Wyatt Federal Building. Â SERA Architects, a local firm, is working with the General Services Administration on retrofitting the building to make it more energy efficient. The 18-story structure was...