The catwalk is the centerpiece of the Morris Arboretum’s new Tree Adventure exhibit, which opens July 4. (Photo by Jainne Perez)

“People need trees,” Bob Gutowski was telling me as we surveyed the vast, verdant canopy above the  Wissahickon Vista.

“Why do they need trees?” I asked, inviting the treetop philosopher to think aloud.

“Do you breathe?” he asked.

I took a quick breath, then I smirked at Gutowski and answered, “Yeah … yeah.”

“Well, guess what?” he said, chuckling between thoughts, “you breathe what the trees produce.”

In his 24 years at Morris Arboretum, a public garden operated by the University of Pennsylvania, Gutowski has noticed again and again how much people take trees for granted. With the Arboretum’s Tree Adventure exhibit, opening July 4, Gutowski hopes to stir up childhood nostalgia for parents and a sense of wonder for their children.

“Most people smile, remember fondly climbing trees,” he said. “And they enjoy an apple pie, and they enjoy clean water from the tap [but] don’t think about the role of trees in each of these things.

“They give us food. They give us pleasure – simple pleasures as children and simple pleasures as adults.”

But despite the universal appeal of trees, Gutowski, the Arboretum’s director of public programs, was faced with a challenge in creating the exhibit.

“The kids want danger,” he said. “The parents want safety. So how do we give the appearance of danger – the excitement and thrill of climbing a tree – without climbing the trees?”

The answer to that question is a zigzagging steel catwalk bounded by native woods (white oak, black locust and beech) that runs 450 feet long and reaches 50 feet at its summit.

Called “Out on a Limb,” the catwalk is the centerpiece of Tree Adventure. And as Gutowski and Sam Pinola, site foreman for CVM Engineering, attest, the assembly was daunting.

“This isn’t like going out on a rope course,” Gutowski said, gazing skyward as Pinola grabbed me a hardhat. “This is really built solidly.”

He paused, collecting his thoughts.

“This is also for us a demonstration of how you can build in a wooded environment with the minimum damage to the trees.”

“Everything after this is gonna be a let down,” Pinola said, returning with an extra hardhat. “We built this massive structure in the middle of the woods. We can’t disturb anything. We can’t knock down a tree.”

“Is it like a Zen experience?” I asked.

“It was an amazing opportunity,” he said. “When we started this in the winter, no one could picture what this would look like.”

The finished product left them awestruck.

“The thing that excites me the most is, when you start walking on it, you can’t see out to the end of it,” Pinola said. “You get so far [and] the entrance disappears. As you keep moving out, it kind of unfolds in front of you and collapses behind you.”

“Have you ever seen anything like this before?”

“I worked on a telescope dome last year in Swarthmore,” he said. “I thought that was gonna be the job I talked about for a while. That’s up there with hanging garage doors at this point.”

Pinola has been equally impressed with the level of cooperation among the different trades collaborating on the project. Steelworkers, carpenters, architects and engineers worked harmoniously and devoted themselves to preserving the natural habitat, he said.

“These guys get out here, and they’re used to working in a very urban environment,” Pinola said. “The amount of knowledge these guys have picked up from being in the arboretum is amazing. It’s like being back in school. I’ve learned from the arborists and the staff here, and it’s all kind of transferred out.

“Guys who were laughing about it at first became very protective of their environment,” he added.

“It’s an exhibit about stewardship,” Gutowski said, “and it’s great to hear that it’s helped train some stewards.”

*   *   *

The handrails guiding us up the catwalk were pale and smooth, but they weren’t uniformly cylindrical. They are irregular by design, according to Gutowski. They’re supposed to create a “tactile association” with the trees from the beginning of the journey into the canopy.

With the exception of taste, every sense was stimulated along the tour. The scent of blooming linden flowers wafted in the breeze as robins rustled leaves and chirped in trees around us.

A hulking chestnut oak had us tilting back our heads as we comprehended its stature and strength.

Gutowski called it Ben Franklin’s tree. He estimated its birth date as sometime before the Revolution.

The catwalk itself will last only 100 years before it needs to be renovated.

Nature 1, Man 0.

As we followed the catwalk’s diagonal planks beneath a wooden pagoda that seemed to have been lifted from Noah’s Ark, Pinola’s point about changing perspectives became clearer. We did not walk a linear path, and everything behind us had transformed into something familiar, but with a new face.

(If I were trying to wring the meaning out of the experience, I might call it a metaphor for life. Let’s just say it brought a wry smile to my face.)

The pagoda split into two destinations: a large-scale replica of an oriole’s nest that affords you an authentic bird’s-eye view of the arboretum floor and an observation deck where you feel as if you’re walking in the treetops. If that’s not liberating enough, you can lie face down on a cargo net fastened to the observation deck’s planks.

“You open your senses, you open your mind,” Gutowski said with a professorial air. “People learn through play, and play is a sensual, multisensory experience. So, if you’re out here and you’re enjoying this, you’re going to start to wonder about it. Wonder leads to questions.”

That’s where you get hooked.

“You start to say, ‘These trees are really important to my life. In my community, who takes cares of the trees? What’s the local regulation? What are the ordinances?’”

“So you see this as a jumping-off point for all sorts of exploration?” I asked.

“Yeah,” he said. “From here, you get to talk about managing this whole forest, the Wissahickon. This is the lungs of the central park of Philadelphia.”

Morris Arboretum is situated at 100 Northwestern Avenue in Chestnut Hill. For more information, visit www.morrisarboretum.org.