Tapping the history of Philly’s trees

The Woodlands, a 54-acre historic site and cemetery in University City, is the final resting place for many prominent Philadelphians. Paul Philippe Cret, the architect, planner, and former professor in what was then called Penn’s School of Fine Arts is buried there.

So are several members of the Drexel family (yes, that Drexel), and renowned American painter Thomas Eakins.

But they’re not the only famous residents located at the historic West Philadelphia site.

The Woodlands also boasts a magnificent collection of trees on the state’s champion list, recognized as being the largest of their species in the Commonwealth. They include an English elm, a hedge maple, and a caucasian zelcova.

“It’s an amazing cemetery, but also, people come here to go bird watching,” says Jessica Baumert, executive director of The Woodlands. “Morris [Arboretum] and Longwood [Gardens] have tours that come here, busloads of people who come here once a year, specifically to come look at our trees. There’s a small group of people who are big-time tree people who know what we have, but I feel like the rest of the city doesn’t really realize that it’s here.”

David Hewitt, a botanist and lecturer in the School of Arts and Sciences, and Edward S. Barnard, a photographer and author of the book, “New York City Trees,” are leading a project to tap into the considerable natural resources at The Woodlands site.

Literally.

Hewitt and Barnard have been leading tree corings of some of the most significant specimens on The Woodlands property—a procedure in which a small cylindrical sample is extracted from the outer bark of the tree to its center.

Hewitt explains that he is interested in the older trees because they can inform people about what young saplings might look in two, three, or nine decades’ time. In fact, he says, places like Central Park and Fairmount Park were originally intended to be public arboretums where people could examine regional trees, see what they look like, and grow those species themselves.

On May 13, Hewitt will lead a walking tour, “Trees of The Woodlands,” in which he will discuss some of the beautiful and historic trees on the site. The tour begins at 2 p.m. and costs $15.

Hewitt’s other purpose for coring the trees is historical in scope. “[If] we know what tree this is, we can identify it. … You can age it, so you know this was here ‘X’ years ago,” he says. “If we’re doing landscape reconstructions, you can actually get good biological data for what the culture was, what was actually there.”

Baumert adds that tree corings can also help The Woodlands better care for some of the site’s significant tree specimens into the future. Plus, coring is harmless to the trees. In a city, says Hewitt, trees get nicked (or worse) all of the time. Coring samples are just a half-centimeter in diameter.

“We’re trying to figure out, historically, what was planted where, so we can, when doing new plantings, use the types of species that were planted here,” Baumert says. “A lot of horticultural firsts happened here, so [we’re] reincorporating that back into the site and trying to figure out, long-term, what trees are the most significant so that we can better care for them and take precautions to make sure they stay healthy.”

On a recent warm, spring-like day, Barnard led the process of coring a leggy, wild-looking mulberry tree at the southern edge of The Woodlands property. Joined by various tree enthusiasts from UC Green, Bartram’s Garden, the Pennsylvania Horticultural Society, and Penn, Barnard first directed people to measure the circumference of the tree with a tape measure to get the DBH, or diameter breast height.
Based on that figure, Barnard decided to use a 24-inch long corer, a T-shaped metal instrument, to drill into the tree. The process of drilling into the center of the tree is done by hand (elbow grease required), and can take some time, especially for a hardwood tree like a mulberry.

The corer is first greased with beeswax, a natural lubricant that won’t rust the metal, and liquefies when it gets warm.

Once the hole is drilled, Barnard slips a long metal stick into the tree to extract the  sample. “It creates a long, thinner-than-a-pencil piece of wood, which hopefully has all the rings in it,” explains Barnard.

“Then you mount [the sample] on a piece of wood and sand it into a half-moon and put it under a stereomicroscope and count the rings.”

Once the sample is extracted (from the mulberry, in several pieces), it is slipped into a plastic tube, labeled, and placed into Barnard’s backpack.

While the present-day Woodlands site contains numerous significant trees, the original estate, developed by 1762 College graduate William Hamilton, was 550 acres, most of it undisturbed virgin forest that extended from Market Street on the north to Mill Creek in the west. According to Mark Frazier Lloyd, director of the University Archives and Records Center and a member of The Woodlands board, firewood was an extremely valuable commodity in the time of William Hamilton; the fact that the family could afford an estate with acres of trees that they didn’t need to cut down made The Woodlands an ostentatious display of the family’s wealth and status.

Lloyd says The Woodlands was sold to the Price family in 1838 or 1840 to be turned into a cemetery in the vein of another rural resting place, Laurel Hill. “William Hamilton had created this botanical garden of about 50 acres around the house, so when Eli Kirk Price [the original cemetery developer] took a look at it, [he saw] a beautiful garden ready to be developed as a cemetery where people can wander about and think peaceful and respectful thoughts.”

Today, The Woodlands is still a rural respite from the city—and a tree-lover’s paradise.

“It’s just an amazing place, it really is,” says Barnard. “I thought I had seen great trees in New York, but the specimen trees here [in Philadelphia] have just blown me away.”

For more information on the May 13 tree tour, call The Woodlands at 215-386-2181.

Originally published on March 15, 2012