Artisan Treehouses Extend Their Lease at Longwood Gardens

The two-story Canopy Cathedral was inspired by old Norwegian churches.
The two-story Canopy Cathedral was inspired by old Norwegian churches. (Photo From Longwood Gardens)
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By Adrian Higgins
Thursday, October 2, 2008

In what was a lonely grove of tulip poplars in the back woods of Longwood Gardens, a ramp rises to a pavilion of stout-trunked cedar trees, smooth and honey-colored without their bark. Beyond, a treehouse is capped with a billowing roof that envelops old trees like the morning mist.

I keep waiting for elves or Hobbits to emerge from the Lookout Loft for a shindig in the pavilion, but the only little people are toddlers in the incessant parade of strollers that ply the boards.

However, you don't need to be 3 to pretend you're a bird. Since April, hundreds of thousands of visitors of all ages have checked out this remarkable treehouse and two others at this horticultural mecca in Kennett Square, Pa. The exhibition, of highly crafted treehouses from two of the best treehouse makers in the country, has been so successful that plans to close and dismantle it around Thanksgiving have been abandoned. The creations will remain at Longwood for possibly five years, said director Paul Redman.

"We have received letters from hundreds of people telling us how much they like these treehouses and that they have to stay," he said.

Bill Allen, of Forever Young Treehouses, which designed and built the Lookout Loft, knows why. "Treehouses are like puppies and hot-air balloons. Only mean people don't like them."

Allen's nonprofit organization, based in Burlington, Vt., was founded in 2000 to create treehouses accessible to children in wheelchairs, and it has so far built 26 of them in 17 states.

The other two treehouses at Longwood, called the Birdhouse and the Canopy Cathedral, were designed and constructed by the Seattle-based TreeHouse Workshop, founded in 1997 by Pete Nelson and Jake Jacob. They have built more than 100 in 32 states and nine countries, mostly for affluent baby boomers who are reliving, lavishly, childhood memories. The typical house doubles as an artist's studio, guest room or "escape pod," Jacob said, though the company has built a few that can be inhabited, with plumbing and electricity.

Longwood Gardens is a former du Pont estate known for its lavish floral displays amid Italianate fountains and elegant conservatories, so it goes without saying that these three treehouses are about as far as possible from your basic assembly of plywood boards nailed into the crotch of a tree.

They were built between February and April and cost about $1 million, Redman said, plus the cost of their special underpinning. Longwood insisted that the structures not be fastened to the trees. They have been built instead on elevated steel supports that include poles resting on small concrete blocks. This so-called pin foundation is positioned to avoid roots and minimize soil compaction.

The Birdhouse, at 255 square feet and 20 feet off the ground, is the smallest and highest of the three and suggests a bluebird box perched in the woods. A massive tulip poplar runs through the heart of it.

The most imposing of the three, the Canopy Cathedral, inspired by old Norwegian wood-frame churches, is nestled on the edge of a woodland overlooking the formal Italian Water Garden. The two-story structure is defined by a glazed gable with diamond-patterned windows and is wrapped by a large balcony with indentations for the 100-year-old tulip poplars.

Nelson had long harbored a dream of building a treehouse modeled on a traditional Scandinavian church. Redman recalls him drawing a concept on a napkin. "We said, 'Do it here at Longwood.' "

One million dollars seems like a lot of money for structures that are temporary, but the project filled several strategic goals for the institution in attracting younger visitors, drawing them to more remote areas of the gardens and in placing more emphasis on the natural beauty of a place known for more formal elements. Redman noted that Longwood's founder, Pierre S. du Pont, bought the property in 1906 to prevent what was already an important arboretum from being cut down for its lumber.

Now the treehouses venerate the trees. The Lookout Loft is the most arboreal of the three. The handrails are made of meandering hornbeam, and the pavilion's posts and roof trusses are stout and branching trunks of eastern white cedars.

"If you don't leave them in the shape of a tree, people will forget what a piece of wood is made out of," Allen said. When the posts and beams are closer to their natural form, "you feel more connected that way."

What isn't obvious is that the whimsy of these treehouses belies the inordinate thought, effort and planning that went into them. The architect of record, Matthew Millan, worked with engineers to make sure that the structures met building codes, including that they could take "live loads" (engineer speak for human beings) of 100 pounds per square foot, 2 1/2 times the code requirement for private homes.

And constructing one is the antithesis of building a production house, where the site is cleared and the building materials are uniform, linear and square, and the object is to finish as quickly as possible. For the crews of artisan carpenters working on these structures, progress is measured in making irregular pieces of wood fit together like a puzzle. "You have got to like wood and make those branches come together, and you have to have a lot of patience," Allen said. "It takes a really good carpenter to build a crooked building."

A project is a success, he said, if the treehouse is one that "the tree would have chosen."

© 2008 The Washington Post Company