Up on the roof...next frontier for urban tree planting?

Landscape+Urbanism: Reforesting Cities:
A great post on Urban Omnibus investigates the potential of implementation of urban reforestation blended into existing buildings in our urban areas. From author Vanessa Keith, author of the article: 'Retrofitting our urban building stock to address climate change need not be limited exclusively to increasing their energy efficiency. If “one of the primary causes of global environmental change is tropical deforestation” (Geist & Lambin, 143), then we should approach the adaptation of our buildings as an exercise in reforestation.'