A tree falls in Princeton, but for a reason

The pair, also known as buttonwoods, were reportedly planted in the front yard of the President’s House — Maclean House used to be the residence of University presidents — to commemorate the repeal of the Stamp Act, architecture professor W. Barksdale Maynard ’88 wrote in a book he is currently authoring about Princeton’s history and campus.

Such centuries-old trees reside in the more historic regions on campus, including Cannon Green, where there are two rows of pre-Civil War ash trees. One of the trees, cut down last summer, was planted as early as 1855, said Maynard, who counted the rings in the stump left on Cannon Green.

Some trees on campus, though not as old, have similar historical significance, including a dawn redwood tree that sits between Prospect House and the art museum. The species was “known mainly from fossils until the late 1930s, or maybe early 1940s, when a Chinese forester found a whole valley of them,” ecology and evolutionary biology professor Henry Horn said “The one that we have at Prospect was one of the first to come out of China through an expedition from the Arnold Arboretum at Harvard.”

With such valuable trees on campus, balancing safety and environmental concerns with historical preservation is essential to the decisions about which trees to cut down and which species to plant to replace lost trees.

University grounds manager James Consolloy noted that the formula followed in making such decisions is “pretty scientifically determined,” and based on the tree’s “potential of failing.” The major concern with the Cannon Green ash was a combination of age and the heavy flow of pedestrian traffic, he said.

“It’s just a very risky situation when what you’re talking about is wood that is 160 years [old] or older supporting such a heavy weight, [that could, with] the slightest amount of wind ... just topple over.”

Consolloy noted that another risk was trees’ root systems, which may be unstable. “There are just too many factors with our trees, from utilities that have been dug in the past and things underground that you wouldn’t see, like old foundations from old buildings [and] rock outcroppings” that impede the full development of the tree’s root system, he said.

Though historical significance is highly valued, Consolloy said, “when the risk outweighs the value of the tree — whether it’s historical or ... a rare species — then we have to go with our risk assessment.” The University makes efforts to save trees, however, like building a “well” around a wych elm whose surrounding land level had to be raised, for the roots to “have the appropriate amount of oxygen,” Consolloy added.

Determining which species of trees should replace lost trees is, similarly, a combination of historical and environmental concerns.

“The main concern is species diversification, both the family and the species,” Consolloy said. “We try to keep no more than 5 percent of one species [or family] in one area. This limits our exposure to disease and insect pressure.”

Maynard noted that he would like to see the historical landscape of the campus preserved, in that a cut tree “will be replaced if possible with the same historic type of tree,” citing his satisfaction with the planting of a copper beech between Walker and Patton halls to replace one that was cut down.

He said, however, that with the “climate getting warmer, causing diseases to spread ... it becomes a big question: do you plant an ash to replace an ash, given there have been ash trees there since 1850, or do you put in some other type of tree that is disease resistant?”

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Horn agreed that the issue of historical preservation of the landscape was difficult to resolve. “[With] the whole notion of trying to make [the campus] look exactly like it has looked at some particular time, there’s no particular time to aim for,” he said.

Horn said he hoped that decisions about campus trees would be made “based on a sense of history and some sensitivity to the fact that this campus is located in a place which, if humans weren’t here, would probably be largely forested.”

Maynard emphasized the need for a study of the older parts of campus to create an approximate timeline detailing when various trees were planted, in an effort to preserve the landscape’s historical integrity. The study, he said, should look not only at colonial trees and trees planted in the early 1900s, but plants placed by Beatrix Farrand, the University’s landscape architect in the 1920s. “Eventually every tree has to be replaced,” he said. “So the question is, do you do it intelligently, or do you do it haphazardly?”

Achieving such a balance between science and history is a difficult task. “Jim Consolloy knows a huge amount about the individual trees,” Horn said. “It’s almost as though he knows them all by name and knows them all individually ... he’s a wonderful person to have in charge of this just because of his range of sensitivities.”

Consolloy said that 25 trees have already been planted this fall. “As we lose trees, we replace them — that’s our basic guideline,” he said. Though as much consideration is given to history as possible, “Our rule of thumb is: the right plant, the right place.”