This summer the Fell Arboretum is saying goodbye to a 100-year-old pine.
Our old Austrian pine (Pinus nigra) is known for its wide trunk, dark gray bark, broad crown, and prominent place in front of what was once the Old Main’s south entrance. It’s part of a collection of trees on Illinois State University’s campus known as the Fell Arboretum.
The arboretum is carefully maintained by Grounds Services personnel. They are the team behind the beautiful displays of flowers, turf, and the diverse trees and shrubs growing throughout the 490-acre campus.
At the end of March and into early April, Bill Koos, superintendent of grounds noticed that some of the Austrian pine’s needles were fading from green, a symptom of illness in trees. Sadly, by the end of May the tree’s crown was almost entirely a dull brown.
The Austrian pine in early 2023 and then in June 2024. Photos by Nick Pershey and Sydney Metternich, respectively.
“It’s hard to determine exactly what it was,” Koos said when asked about the cause. Austrian pines are susceptible to several pests and diseases, some of which can be fatal.
Pine wilt, for example, is a disease caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, that can kill infected Scots pines (Pinus sylvestris), Austrian pines, red pines (Pinus resinosa), and other pine species in a matter of months. Nematodes are worms that are often associated with damage to plant roots, however, PWN travels via sawyer beetles (Monochamus species).
Sawyer beetles burrow into pine wood to feed and, in the process, leave wounds which PWN use to invade the tree. As the nematode feeds, resin from the tree intended to seal off wounds leaks into the plant’s other organs and stops the plant from being able to move water to its needles. Without water the needles cannot function properly and wilt.
Why is it so hard to know what happened to our pine? Pine wood nematodes also feed on fungi in pines that are already dying, which means that even if we were to find PWN in a tree, it’s not necessarily the only cause. Age and environmental stress also play a role in a plant’s ability to fight disease.
“It’s an aggregate of probably many different issues: age, it probably does have some soil-borne issues, it probably has some foliar issues,” said Koos.
What’s curious is that just about 100 feet away a few other pines fell ill and had to be removed in the last year. It’s reasonable to believe these pines were affected by the same diseases and stressors, but trees of different species and ages decline in heath at different rates, so remediation and pinpointing the time of infection is difficult. The Fell Arboretum contains thousands of trees and hundreds of species, all of which require close observation.
Our old pine was one of our collection’s approximately 169 trees belonging to the Pinus genus and one of 67 Austrian pines. Since the species was introduced to the United States in 1759, it has long been a favorite for its tolerance to urban conditions, ability to stabilize soil, and protection it provides from the sun and wind.
This iconic pine is thought to first appear in records of the 1907 Index yearbook, which makes the tree at least 117 years old as of 2024. It stood by as a witness to war efforts, women’s voting rights come to realization, concerts, celebrations, and countless graduations.
The pine will be taken down the last week in June in preparation for summer activities on the quad. While we are saddened by this tree leaving our arboretum, we celebrate it for the comfort and shade it’s provided for our campus community over the many years.
