Summer researchers build comprehensive tree database that will serve multiple purposes

Aug 12, 2015

A research team of “tree geeks” spent the summer getting to know all the trees that adorn the North Central College campus. It took four weeks for them to identify all the species, measure each circumference, tag each with a number for future reference and assign GPS coordinates to the location.

“The goal for this summer was to collect baseline data about the College’s trees for the future,” says Silvia Alvarez-Clare, assistant professor of biology. “This tree inventory helps us know which tree species we have on campus, where they’re located, the microenvironments where they thrive and what benefits they provide, like improved air quality, water retention and aesthetics. “

The researchers and self-named “tree geeks,” Andrew Munoz ’15 and Jacqueline Pfaff ‘16, carefully logged the data for 726 trees. After identifying the species—not always an easy task—they would take a circumference measurement to determine the size of the trunk. From this measurement they determined the basal area, which is the land area that is occupied by the cross-section of the main trunk.  A further calculation using allometry produced data on the total biomass of the tree. A future project may involve removing a small core from the trunk to count rings and assess the age.

The team learned that the largest tree on campus (based on basal area) is the sugar maple located at the southwest corner of Oesterle Library. Munoz and Pfaff decided that their favorite trees are the Kentucky coffee tree located on the east side of the library and the stately sycamore that shades the area between Old Main and the Harold and Eva White Activities Center. The parkway trees owned and maintained by the City of Naperville were included in the study.

All trees now have GPS coordinates and with geographic information systems (GIS) data, users of the database will be able to click on a dot on a map to retrieve information about each tree. Eventually, the team would like to collaborate with a bioinformatics major to create an app with a walking tour of the campus forest. All the trees are numbered, indicated on an aluminum tag in the bark.

“This is an important sustainability project for us, as well, because we want to improve the diversity of our trees and plant native species,” says Brittany Graham, the College’s sustainability coordinator. “In the future, we hope to apply for designation by Tree Campus USA and this study provides the needed data.” The Arbor Day Foundation awards colleges and universities a Tree Campus USA designation if there are programs in place to manage the campus forest, involve students in the effort and connect with outside organizations.

For Alvarez-Clare, the study also has been a learning process despite her studies in the field of botany. “I’m from Costa Rica and studied tropical plants and trees—these species are all new to me,” she says. “Overall, my goal is to expand the environmental focus of North Central’s biology department. We can use this tree data in future student research projects and for teaching.”

Pfaff, a biology major, was participating in the College’s Summer Undergraduate Research Colloquium and wants to present her research at the National Conference on Undergraduate Research in 2016. She will continue to work on quantifying the role that campus trees play in mitigating carbon emissions. Munoz, a biology alumnus, plans to relocate to Portland, OR, to pursue work in the environmental field.

“We are honored to be known as tree geeks,” adds Munoz.

Number of trees: 726

Number of Species: 84

Percent healthy: 96 percent

Largest tree on campus: sugar maple near Oesterle Library

Most common species: white pine, Norway spruce, sugar maple