Goodbye to an iconic tree

Marking the end of an era, Penn’s historic “Quad elm” is due to be removed the week of July 25 due to safety concerns.

In place in the heart of Penn’s Quadrangle dormitories for more than a century, the tree has been steadily declining in recent years, despite the exhaustive efforts of Penn staff, Morris Arboretum Urban Forestry Consultants, and other contracted arborists. The site will be replanted at a future date with a trio of white oaks, a native species.

“The Quad elm is such an iconic tree,” says Bob Lundgren, University landscape architect. “Old trees like that create a special place, a place to reflect, and they are significant parts of the campus landscape.”

There are few trees that rival the American elm’s historical significance in Philadelphia. Most notably, the original ‘Treaty” elm was a large, wide-spreading tree under which William Penn and Tamanend, a chief of the Lenni-Lenape Nation, are believed to have signed a treaty of peace in 1683. Descendants of this elm are still scattered around the region at various arboreta and gardens, including one on Penn’s College Green. Over the years, staff at the Morris Arboretum have produced many clones of the tree to distribute.

The Quad elm is another majestic American elm. Planted around 1910, the tree grew as the University did, its canopy spreading to about 85 feet wide and its trunk growing to almost 10 feet in circumference.

View large image

Generations of students have enjoyed the benefits that the tree has provided, including its far-reaching shade and picturesque fall foliage.

The tree’s appearance is rather unusual relative to other American elms because it’s not as tall, and the branches arch slightly downward, resulting in an almost closed, dome-like crown. The origins of the tree are uncertain, leaving the variety or cultivar up for speculation.

The exact cause of the Quad elm’s decline is unclear. In recent years, the tree’s caretakers have treated it for Dutch elm disease (Ophiostoma ulmi), the most common cause of death in native elms in the Philadelphia area, but test results rule it out. Bacterial leaf scorch (Xylella fastidiosa) could be a cause. The tree tested positive and has been treated for this disease, which is relatively common for oaks, but is not as frequently seen on elms. Branch samples also tested positive for Botryodiplodia canker, a fungal pathogen that affects the living wood and causes early leaf dieback.

View large image

Jason Lubar, associate director of urban forestry at the Morris Arboretum, says he will miss the tree’s presence on campus. “The Quad elm was a wonderful, spreading umbrella of green and really defined the space it was in,” he says. “I was surprised how quickly it declined after years of good biological and structural health, even with the best of care. It’s a tree that will be missed by all on campus, but removing it is an opportunity to plant more trees for the future.”

If the wood is of high enough quality, Penn staff will count the growth rings to confirm its age.

And, as a silver lining, the removal allows the University a rare opportunity to replant in a wide open space. Lundgren and colleagues will be checking with nurseries to find a selection of three healthy, attractive white oaks that will grow and create new and lasting special space, for students and wildlife alike.

“White oaks are great wildlife trees,” says Lundgren. “They’re one of the most efficient species at attracting pollinators and butterflies and all those good critters. They also have great longevity, better than elms. With luck, the three we plant will be growing there for 200 years, serving generations of students to come.”

Adapted from a Morris Arboretum blog post written by Andrew Conboy, the Martha S. Miller Endowed Urban Forestry Intern.