Urban Oasis Guides Visitors Through the Forest and the Trees

'Going there and looking is just the beginning," says Robert Cook. "The Arboretum has hidden layers of meaning you don't get just by visiting the grounds."

Bow-tied and bespectacled, the director of Harvard University's famed Arnold Arboretum in Boston's Jamaica Plain neighborhood is talking about the lifetime of interest that may lie in wait for those who come to view the arboretum's inviting 265-acre sweep of trees and plants. It was designed by the great 19th-century landscape architect Frederick Law Olmsted.

"When people first come in," says Mr. Cook, "they probably do so for recreation and as an aesthetic experience. But if their interest is piqued," he says, "that is when they can really begin to learn. They see how people have used the landscape over time. They can take adult education classes" and go on to a serious study of this world.

To this end, the arboretum - the oldest in the United States - is marking its imminent 125th anniversary with a new exhibition, "Science in the Pleasure Ground," designed to showcase the function and history of the arboretum and its place in the "emerald necklace" of Boston's public park system.

In the main room of the Hunnewell Building, this exhibition offers an impressive scale model of the arboretum itself, surrounded by five exhibits that explore - through visual displays and interactive devices - the institution's historical role. These activities include botanical research and exploration, forest resources, the use of wood in early American industry, and American horticulture.

The 8-foot-by-16-foot glass-encased model of the grounds strikes the eye. Here features of the arboretum are represented in dazzling detail - trees, roads, buildings - even occasional human figures, dwarfed by the broad scope of the model.

"You can come to the arboretum at any time of year now and it's always spring," says the exhibit's curator, Sheila Connor, a lively figure who is turned on by plants and trees the way some people are by rock music. "We have everything blooming at the same time, so you can tell different collections apart" because of the contrasts in color. For instance, that dash of pink and red at the far end, she notes "is the crab apple collection."

For Carol Donnelly of York, Maine - a longtime arboretum visitor and now a volunteer - the exhibition is a much-needed guide.

"It's hard to visualize the entire scope of the place," she says, "because it's so vast. This helps you understand what it all is. I think it captures it very well and highlights what has been going on since the Aboretum was first created."

Visitors or volunteers like Ms. Donnelly who have a serious interest in the Arboretum can have a long-term involvement with ecology or some other part of the facility's historic role.

That role is a dual one - to serve as what Cook calls "a place of research and also of public education." Since its establishment in 1872 by Harvard University's Charles Sprague Sargent, Arnold Arboretum has been a national model in both research and people's changing awareness of landscape and the natural world around them - from forests to their own back yard.

And now, as a center for resource management and conservation, the arboretum epitomizes the new role played by places like this in connecting people to plants, and in helping them understand the need to protect the landscape around them.

Touch one of the buttons along the side of the glass enclosure and a light shines on some spot on the model - a road, a stand of trees, or perhaps the site of American Indian artifacts.

"The living collections department sited the trees on the model," Ms. Connor says. "They wanted the dumpster truck and the cherry-picker to be placed just right, and there was a great deal of argument as to where exactly each tree went. 'No! No! You've got to move it over a littler bit.'

"And do you know about Corky?" asks Connor. "It was the one tree - an Amur cork - in the arboretum that children could not resist climbing. It came crashing down about a year ago and we saved its trunk so people could sit there. That, too, is in the model."

But you know you're not in Disney World as you survey the sober-minded and sometimes scholarly displays placed around the room.

They range from photos and specimens of plant-gathering expeditions in China to an audio section that lets you hear Martha Stewart - yes, Martha Stewart - reminisce about the trees she remembers in her childhood.

Looking ahead to new features, Cook cites a new orientation system to be installed. "This one will have signs set entirely in the ground," he notes, "so it does not obstruct the view of trees."

The basic idea, says Cook, is that, "We are a sanctuary in the middle of Boston and we want to keep it that way."