Came across the site below today. I can attest to the incredible difference that tree shading makes at our house. We now rarely require AC in the summer as the Maples to our south have matured. http://www.extension.org/trees_for_energy_conservation Urban Forestry Conservation experts have come together to provide you with timely, up-to-date information on best practices for the use of trees in an urban environment. Urban Forestry Energy Conservation Tree Care Tree Shade Tree Selection Tree Placement Windbreaks Passive Cooling Get answers to your Urban Forestry and Energy Conservation questions by Asking an Expert.