How often do you think about the trees on campus? Did you know the trees on campus are actually “working” for us? Besides being beautiful and pleasant places to sit under on a hot summer’s day, trees provide numerous additional benefits to people, including economic and environmental ones. These benefits, termed ecosystem services, help people in urban areas by alleviating the effects of impervious surfaces like asphalt and concrete as well as reducing the heat island caused by infrastructure and buildings. Tools, like the US Forest Service’s iTree, have been developed to quantify the monetary value of these services, helping the public fully realize the value of the trees around them.
Wondering how these tools work? Let’s use the enormous bur oak tree in front of the IMU as an example. Knowing just the size and species of the tree, we can estimate financial benefits based on calculations from extensive research. This particular oak tree alone provides annual benefits of $353.55! Here is the breakdown of that number:
- Preventing flooding by slowing water down: $200
- Energy savings by keeping buildings shaded: $100
- Air pollution removal: $30
- Aesthetic value: $30
In addition, the cost to replace a tree this size would be $8,282, which includes planting costs and maintenance over time (but does not include lost benefits each year).
During my work with the IU Office Sustainability, I have inventoried most of the ash trees on campus. Let’s look at that population of trees to see how much benefits they provide the campus. There are approximately 515 ash trees on campus; most of them are white ash trees, followed by green ash, and then a small proportion are narrow-leafed ash and blue ash trees. The total benefits of all of these trees on campus is $104,749 per year! And that is just for a single family of trees.
IU has an estimated 12,000 trees on campus, and ash trees are a mere 4% of that total. If we say the ash tree population are representative of the greater tree population at large (which is a big assumption), that would mean IU’s trees provide over $2.4 million in benefits per year!
If you’re interested in more information about the campus tree inventory efforts, check out the IU Office of Sustainability (IUOS) website, or I can be reached at the via email (firstname.lastname@example.org). Also, if you want to learn a whole lot more about the wonders of urban trees and have a spare a slot for another class in the spring semester, think about taking Professor Burney Fischer’s Urban Forestry Management (SPEA E422 or E522) the next time you are choosing classes. In addition, there are multiple groups on campus and the community that help plant and maintain trees, like IUOS and IU Bloomington Community Orchard. Finally, watch for a campus Arbor Day tree planting event this April to learn about tree planting techniques and how to inventory them.