The stately Penn State elms have been the living witnesses to our roots as a University, dating back to the1890s when the first elm tree was planted. They have watched history unfold through generations of students and have stood to symbolize Penn State as much as the iconic Nittany Lion Shrine and Old Main, making them near and dear to Penn Staters everywhere.
Penn State's treasured elm trees are slowly disappearing. Elm yellows disease, a deadly bacteria-like infection for which there is no known cure, has infected 65 of the 290 trees (as of June 2011), more than 22 percent of all elm trees at University Park since the disease was detected in 2008.
Elm yellows, also known as elm phloem necrosis, is a disease specific to North American elms. The bacteria-like organism infects the root cells and the inner bark that carries nutrients to all parts of the tree, but does not invade the core of the tree. The disease essentially prevents the tree from receiving adequate nourishment, ultimately killing it. Once a tree dies, so does the whitebanded elm leafhopper, leaving the elm wood unaffected.
Learn more about the elms’ battle.
Since the elms yellows disease was detected on campus, Penn State plant pathologists have been racing to find a cure. The University has been injecting both healthy trees and infected trees with a fluid analogous to an antibiotic, which has seemed to help slow the spread of the disease.
When the elm trees are removed, they are being replaced with several different species of trees that have a higher disease resistance while still offering the majestic canopies associated with the elms.
Wood from removed elm trees has been used to create The Penn State Elms Collection, with a portion of the proceeds will go toward planning replacement trees in the historic core of the Penn State campus.