A tree’s quantitative benefits are not always easy to measure. There are numerous factors to be taken in to account, and many possible benefits to try to nail down: added value to the sale price of a home or business, psychological benefits, pedestrian safety, and of course environmental impact are just a few of the possible choices.
Casey Trees, in partnership with Davey Tree, has a handy dandy tree benefits calculator to help everyone (residents of Washington DC especially, to which this calculator is specific) understand the the overall impact of trees, including their affect on stormwater, electricity, air quality, property value, natural gas, and CO2. It’s very easy to use — just enter the tree species, DBH (diameter at breast height) and whether the tree is in front of a single- or multi-family building. Math-heads curious about the model used in this calculator can read more about it here.
For people outside the DC area, there is a national tree benefits calculator as well. It works basically the same way, but has a greater variety of tree species and more possible tree locations to choose from.
It’s fun to run the trees around your home through the calculator to see what they turn up. One really nice feature of these calculators is that they tell you how much greater the dollar benefit of a bigger tree would be. It’s an additional incentive, if you need one, to pay attention to how trees are planted in your community and to think about their care and upkeep. Naturally they have not yet figured out a way to factor some of the most critical but slippery tree benefits, such as the psychological effect on human health and the importance of city trees as wildlife habitats — but maybe someday we’ll be able to measure that, too.