Sustainability at Lewis

Campus Tree Evaluation

Campus Tree Evaluation

In a Conservation Biology course, six Lewis University students have further defined the value trees have on campus. Ariel Colman, Kaitlyn Curtis, Andrew Gestautas, Lara Jones, Rebecca Preisler and DJ Volkman examined the monetary value trees have based on storm water interception, energy conservation, CO2 removal, and the increase in property values due to trees. These six students have measured over 700 trees in the inner circle of University Drive, the project will continue in the following years to include more sections of trees on campus.

Here are their findings thus far:

Storm Water Retention

Preventing storm water runoff is an important sustainability issue for Lewis University, due to the proximity of the campus to the endangered Hines Emerald Dragonfly Habitat. Trees are able to hold rainwater in bark and branches, slow raindrops before hitting the soil and therefore slowing the erosion process, and store rainwater in roots. With the help of trees and other practices on campus, the amount of storm water lost to run off on campus greatly diminishes. By properly managing storm water and planting native species of plants, Lewis University is able to save money on irrigation costs on top of keeping precious water in a very important habitat.

The total number of gallons of storm water saved each year is 738,581. The average is 990 gallons and the highest individual tree value is an American Sycamore which saves 7,239 gallons/year.

Energy Conservation Value

A trees ability to shade a building in the summer months, block the wind reducing heat loss and to cool the air through evapotraspiration leads to energy savings for the University. With all the trees surrounding campus buildings, energy savings from trees is significant. Students were able to calculate the total kilowatt hours (kwh) of electricity that have been saved by the presence of trees.

In total Lewis University trees have saved 89,901 kwh with an average of 120.5 kwh. The highest individual tree is a Silver Maple with 3,225 kwh.

CO2   Removal

Carbon Dioxide is a dangerous greenhouse gas that has been linked to global warming, Lewis University is proud to be taking steps to reduce our carbon footprint. Trees are able to lock in CO2  using their roots, trunks, stems and leaves. Trees planted near buildings are also able to reduce heating and air conditioning demands thereby reducing emissions from power plants.

In total trees around campus have sequestered 291,714 pounds of carbon with an average of 391.04 pounds. The highest individual tree, a Silver Maple, has a value of 2,332 pounds of carbon sequestered.

Property Value

Trees bring a level of aesthetic value to campus, and with Lewis University earning the status of Tree Campus USA each year since 2009, there is a strong sense of beauty and species diversity on campus. The property value or curb appeal of planting a wide variety of trees can be monetarily measured, but there are other properties of trees that cannot, such as cultural values, historical significance and the sense of community that is created by trees.

The average property value per tree was found to be $13.55, which leads to a total property value increase of $10,107 for campus.

Total Value

Adding up property value, CO2 removal, energy savings, and storm water retention, Lewis University’s average total value per tree is $72.32. The total value of the 700 trees examined in the inner circle of University Drive is $53,947. The highest individual tree value is a Honeylocust with a total value of $400.

These values are currently only looking at a small piece of the tree population on campus will fluctuate as more data is collected to include more trees.