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The Trees of 魅影直播

So many magnificent trees thrive on campus. The Bulletin unearths their stories.

The fair green hill

鈥淚n the very beginning, 魅影直播 was favored by its situation, for it stands on the top and extends down the sides of a fair green hill conspicuous for its beauty,鈥 wrote Helen Flexner (Class of 1893) in the January 1908 issue of the 魅影直播 Alumnae Quarterly.

Flexner went on to describe the architectural beauty of the campus鈥攖he 鈥渉armonious color and line鈥 of its distinguished buildings鈥攁nd its educational program and 鈥渟tandard of scholarship.鈥

Yet throughout, she pays homage as well to the natural beauty of the campus and particularly to the trees of 魅影直播鈥攖he 鈥済reat forest trees,鈥 鈥渙ld apple trees, gnarled chestnuts, and maples that turn golden in the autumn,鈥 and 鈥淛apanese cherry trees whose shower of pink blossoms looks so particularly pleasing in the spring time.鈥

There are 1,298 large trees on the main campus鈥攎ore than 3,000 when the Graduate School of Social Work and Social Research and Morris Woods are added into the count.

More than 100 years after Flexner鈥檚 time, many of the species she so admired are still here. Back then, Asian varieties were much prized, and many such specimens鈥攁nd not just the cherry trees鈥攎ade their way to campus early on. When Dawn DiGiovanni, associate director of facilities for grounds who started her career at the U.S. Forestry Service, first arrived on campus, some of those specimens had her stumped.

鈥淲e try to mix in the new with the old,鈥 she says, 鈥渂ut the mindset has changed, and people want more native specimens. They survive better. We don鈥檛 even want to go too far from Pennsylvania to buy them. We鈥檝e found that trees grown in this area survive in this area. They鈥檙e adapted to the local climate, soil type, and wildlife.鈥

DiGiovanni鈥檚 first priority is health and maintenance. 鈥淢y biggest job is to keep the trees as long as I possibly can. I鈥檓 constantly walking campus to monitor how they鈥檙e doing.鈥 Still some won鈥檛 make it: bad storms, wind shear, rot, and disease can all damage, and eventually kill, a tree.

When a tree is lost, a tree is planted. 鈥淲hen our beautiful old linden had to be taken down, we put in a large-leafed magnolia,鈥 DiGiovanni says. 鈥淲e replaced a weeping hemlock over at Taylor recently, and when Park Science was being renovated, we transplanted five trees鈥攁 dawn redwood, a crepe myrtle, and three Japanese maples鈥攐ver near Gateway. I try to rescue as many trees as I possibly can.鈥

the wood wide web

It may seem a romantic notion鈥攖hat trees communicate with one another鈥攂ut it turns out that, much like Mawrters, they like to talk.

Over the past few decades, scientists have identified a complex system that facilitates communication among trees in the form of an underground fungal network that connects them to one another. It鈥檚 being called the Wood Wide Web.

More formally known as mycorrhizal networks, these webs are formed by a system of mycelia (the threadlike, vegetative part of fungi) that sprawls underground and links the roots of plants. For the fungi in this association, the plants provide food (i.e., carbohydrates). In return, the fungi provide nutrients such as phosphorus and nitrogen, help the trees absorb water, and boost their immune system.

What鈥檚 more, these mycorrhizal networks enable trees to network with one another, share water and nutrients, and perhaps send distress signals about drought, disease, or infestation. Some scientists believe that certain hub trees perform a kind of nurturing role, particularly toward younger trees. One study reported that saplings growing in shaded areas received more carbon from donor trees than those with abundant access to sunlight鈥攁nd hence the ability to photosynthesize.

Plant a Billion Trees

Using data from 1.2 million forest tree plots in more than 70 countries, an international team of scientists recently mapped the Wood Wide Web, and what they found has some serious implications for climate change.

Their research showed that certain types of fungi鈥攖hose that support carbon stores in the soil鈥攁re being replaced by fungi that release carbon into the Earth鈥檚 atmosphere.

Significantly, that carbon hog, called ectomycorrhiza (EM) fungi, prefers cooler climes, while its carbon-spewing cousin, arbuscular mycorrhiza (AM) fungi, dominates in tropical regions.

This map of the world鈥檚 fungal networks reveals that more than 60 percent of the world鈥檚 trees are connected by EM fungi鈥攖he good guys that lock up carbon. But with rising temperatures, scientists predict a decline in EM fungi and a consequent flourishing of AM fungi.

While not exactly good news, these results have spurred on reforestation efforts. For one, the UN鈥檚 Trillion Tree Campaign has planted, to date, more than 13.6 million trees in a global campaign as a response to climate change.

A Living Campus

For Earth Week 2019, a Class Year Tree Planting event found members of each current class, including McBrides, selecting and planting specimens: cherry trees near the hammocks, crabapples by the Campus Center, and a magnolia next to Radnor.

Rachel Hertzberg 鈥19, who helped plant the senior class cherry tree, reported that the work, while harder than expected, was worth the effort: 鈥淎fter all the trees were planted,鈥 she blogged, 鈥渨e talked about coming back to 魅影直播 someday and seeing how tall they had grown. One day they will be as tall and strong as the trees along Senior Row, but for now they are just barely twigs.鈥

Like Hertzberg, DiGiovanni looks to the future: She hopes to continue Earth Week class plantings and to do more with the Morris Woods. 鈥淎 lot of people don鈥檛 even know it exists,鈥 she says, 鈥淎nd the trees have been there for so long鈥攖hey were there when the Vaux family owned the Russian House鈥攁nd nobody has touched them.鈥

In the meantime, she鈥檚 thrilled by Living Campus, a new interactive map that features the most significant trees on campus along with sculpture and benches (as of this writing, still a work in progress; check back for more!). Available online, the map was developed by a team that included DiGiovanni, Kate Fernandez (Alumnae/i Relations and Development), Alicia Peaker (Library and Information Technology), and Robin Parks and Christian Zavisca (Communications).

For more about its development, see 鈥淟iving Campus.鈥 To visit, go to .

Published on: 11/16/2019