In most condominium projects the signature unit is the penthouse, but at the Boxwood on Queens Road the must-see condo is "the treehouse."

The limbs of a 100-year-old oak tree lean over the terrace almost close enough for a resident to reach out and touch.

It didn't happen by chance.

"We wanted the Boxwood to look like the tree had grown around the building," said developer Brian Speas of Carnegie Co.

If it weren't for the construction fence and trucks parked in front, the 1920s English design building probably wouldn't stand out as new.

That, too, is part of the plan.

The developers, working with architect Harry Schrader of Schrader Design, wanted to give the three-story brick building an old-fashioned elegance using the majestic tree as a centerpiece.

All but three condos in the 24-unit, $7.5 million project in the 200 block of Queens Road have sold as it moves toward completion in late October.

The 80-foot-tall tree didn't qualify for protection under the city's commercial guidelines because of its distance from a public street, but Speas said removing it was never considered.

Such decisions are becoming more common in the Charlotte area as developers realize the aesthetic and financial value of preserving old trees.

Charter Properties, for example, worked around a 100-year-old willow oak outside its Jefferson Square Condominiums at Seventh and Church streets in Fourth Ward.

And developer First Colony Corp. recently preserved two large trees outside a three-story office building under construction at 1011 E. Morehead St.

Small towns around Charlotte also are adopting tree protection ordinances and requiring developers in some cases to submit landscape plans showing how they would preserve trees.

To protect its 100-year-old oak, Speas said, Carnegie Co. brought in a tree expert, erected a retaining wall, installed a temporary irrigation system, added fertilizer and pruned dead wood.

It's too late to buy the 1,300-square-foot treehouse unit. Speas said a buyer has it under contract for a base price of $276,000.

Carnegie Co. priced it slightly higher, he said, because it had a third-floor, corner view, not because of the leafy terrace.

Boxwood's three remaining units list from $318,000 to $330,000. The most expensive condo -- 1,800 square feet -- sold for a base price of $340,000.

Every unit will have a balcony or terrace. Residents will share a private backyard that includes an herb garden, a butterfly garden and a perennial garden.

Secure parking will be under the building. Upper floors will have elevator service.

A aging four-story apartment building was demolished to make way for the project near Queens Road and Third Street, not far from the Presbyterian medical complex.

Schrader and his associate, project architect Andrew Woodruff, worked on the design with Via II Architects.

Choate Construction Co. is the general contractor. Boxwood LLC, which includes Speas and partner Patrick Hunter, is the development entity. Carnegie Co. is handling sales.