Research at Arnold Arboretum
Part 2 of 2-part series on the little-known research at Arnold Arboretum. For Part 1, see www.JamaicaPlain
Arnold Arboretum’s gene pool of living plants is now an international resource, with samples sent to researchers worldwide. The arboretum has its own researchers as well, and director Bob Cook’s new goal is for it to become the leader in the evolutionary biology of trees.
One arboretum researcher recently won a $3 million grant to study phytochromes, the pigments that tell plants whether they’re in light or darkness. This very basic behavior—plants crave and fight for light—may reveal very early evolutionary relationships and divergences.
The Dana Greenhouses are the only obvious research facilities in the arboretum. The days of former horticulturist Donald Wyman, a pioneer of home gardening techniques, are gone, and the main business today is propagating experimental plants for researchers. “I’m actually predicting that in 10 or 15 years, there will be a convergence of horticulture and evolutionary biology,” Cook said.
But the greenhouses still create some new home-use cultivars, said Robert Surabian, the arboretum’s director of development. A recent example is a type of Boston ivy called Fenway Park—the ivy that grows on the famous ballpark. It used to be notoriously hard to grow until the arboretum—which identified the species—bred a more suitable strain and gave it away. Fenway Park is now widely available in commercial nurseries, but rarely with any acknowledgement that it came from the arboretum.
Another major research effort, out of sight and out of mind for visitors, is the arboretum’s wide-ranging study of Asian jungles.
“Not many people know that the arboretum has a deep interest in tropical
biodiversity,” Cook said.
The arboretum operates three major National Science Foundation grants for plant exploration in Papua New Guinea, Thailand and southwestern China. This work includes sending back samples, including frozen DNA.
In collaboration with the Smithsonian Institution, the arboretum oversees plots of southeast Asian forest through the Center for Tropical Forest Science-Asia Program. Working with locals, researchers regularly conduct a census of every significant plant on the plots, both as raw data and to teach basic science and forest management to residents—part of a long-term solution to saving threatened jungles. One plot in northern Borneo has about 1,200 plants—or about 12,000 individual stems—to count every time, Cook said.
This jungle work is another legacy of former director Peter Ashton, who last month won the prestigious Japan Prize for his groundbreaking tropical research.
At the same time, there’s science happening on the arboretum’s grounds as well. Harvard’s forestry program is studying soil and vegetation dynamics on Hemlock Hill, which lost its hemlocks to disease in recent years.
Boston University Prof. Richard Primack has been using the arboretum as part of a case study in evidence for climate change. Using the extensive Herbaria collections, he compares the current flowering dates and cell sizes of arboretum plants to those of many years before. In the arboretum, Cook said, Primack has found that plants are flowering an average of a week earlier than they did about 70 years ago—an indication of a temperature increase.
Another little-noticed attribute is that the arboretum collection is always a work in progress.
“It’s a very dynamic landscape, and people don’t understand that,” Surabian said.
A perpetual inventory process reviews each plant once every three years or so. Some plants are removed while others are added. In the context of 265 acres, such changes are rarely noticeable.
The arboretum is bringing on a new curator to review the collections. One goal already in mind is to expand the already world-class collection of maple trees, Surabian said. But it’s likely you won’t notice most of the changes.
Park and lab
In fact, many visitors don’t notice they’re in a precious plant collection at all. Cook and Surabian acknowledged that the public park aspect has its conflicts.
Asked whether visitors steal the metal identification tags hanging on all major plants, Surabian said, “All the time. We’re replacing them all the time.”
A much bigger concern, however, is tree-climbing, a practice that famously killed a 120-year-old arboretum tree in a dramatic 1995 incident involving 22 schoolgirls and a weakened branch, as the Harvard Crimson reported at the time. “We have trees that can be loved to death,” Surabian said, adding that foot traffic can compact soil and suffocate tree roots.
Asked about the arboretum’s plague of illegally off-leash dogs, Cook spoke judiciously, emphasizing that the City of Boston carries responsibility and liability for that. But, he said, dogs are more of a danger to people than they are to the plants.
All that being said, Cook and Surabian emphasized that the vast majority of park visitors are among the arboretum’s biggest assets, self-policing and publicizing it better than staff could ever hope to. After all, the sheer aesthetics of the place aren’t lost on the administration, which brings potential donors there to wow them.
Cook recalled taking one such VIP, a member of the Du Pont family, on a tour scheduled on short notice, without the double-checking of the grounds he would prefer. It turned out he had no cause for alarm.
“It was magnificent,” Cook said. “There was very little litter. [Visitors] come to this landscape…with an appreciation for the distinctiveness of this place.”
That still doesn’t translate to scientific understanding. When the arboretum’s research is mentioned at all—usually with no more explanation than the word “research”—it’s always in the context of an inevitably contentious development plan.
“One theme that came out is, we’re very mysterious,” Surabian said of a recent visitor survey. “We need a better way to talk about ourselves.”
To that end, they have a new “branding” effort, including a new logo, with new signs and maps going up shortly. They’re also focusing on building not only a new lab, but also better public amenities. One possibility, Surabian said, is a new building for the popular Larz Anderson Bonsai Collection. The overarching theme, he said, is that the arboretum’s various uses are “not mutually exclusive.”
Cook is known in Jamaica Plain as an administrator, almost always talking about some piece of land in the public eye. But ask him about white violets, his old field of study, and he will respond animatedly. The plants send out runners that sprout into identical clones, in effect crawling slowly across the ground, perhaps in search of nutrients, he explained.
“You have to ask why some plants reproduce that way,” Cook said. “Is it really reproduction, or just another form of growth? What the plant is really doing is moving in space.”
It’s a reminder that where arboretum visitors see a solidly familiar public resource, arboretum researchers see endless new questions to ask and answer. If the arboretum is the tree depicted in its new logo, it has park uses as its sunlight and laboratory research as its soil.