Trees provide communities with many benefits: They offer energy-saving shade and shelter from wind, absorb carbon dioxide, create habitat for birds and other wildlife, and add beauty and value to homes and businesses. But how to quantify that benefit so it can be factored into decision making? The USDA Forest Service’s i-Tree suite of public domain software gives urban foresters, homeowners and others a way to put a dollar value on the ecosystem services urban trees offer for better planning, education and action. Tools include i-Tree Eco, which calculates the value of the entire city forest, i-Tree Streets, which puts a price tag on street trees, i-Tree Hydro, which simulates effects of changes in tree cover on watersheds, and i-Tree Design, which lets users see what benefits would accrue if they planted trees in various locations around their homes. Photo by Andreas (Flickr | Creative Commons)