TOWN OF FAIRFIELD — Just down the road from Nina Leopold Bradley's quiet home on the Aldo Leopold Memorial Reserve, an enormous undertaking has taken shape in Sauk County. The 13,000-square-foot, $4 million Aldo Leopold Legacy Center — a flagship structure for the foundation of the same name and a case study in sustainable building — held its grand opening April 22.

Bradley, 89, the eldest daughter of famed conservationist Aldo Leopold, spent her teenage years refurbishing a chicken coop into the "Shack" that would become a retreat for their family of seven and toiling to bring a sandy, wasted farm back to life.

"Growing up as we did, I don't think any of us could have anticipated what has happened. It's really quite stunning," said Bradley, who co-founded the Aldo Leopold Foundation in her home in 1984. "I don't know if my father ever, ever could have anticipated what has happened in his name and with his basic philosophy."

If the Shack served as a metaphor for Leopold's Land Ethic — protecting and preserving the environment as an ethical obligation — then the Legacy Center may just cement that philosophy in the 21st century.

The Leopold family, Bradley said, is thrilled.

"We hope it will be sort of a central station for people that are interested in my father's main thesis, which is man living in harmony with the land," she said. "So many people don't even think about land. They think groceries come from the grocery store. So we hope this will be a place where people will change their thinking and their philosophy."

The Legacy Center is an exercise in regeneration, mirroring what's been happening on the reserve for decades.

Every feasible part of the building was harvested from the forest the Leopold family planted or preserved: the wall paneling and 20-foot-long trusses of Leopold pine, the ceiling and cabinets of red maple, the floor and bookcases of cherry.

"We hope this could be a new model for sustainable forestry and an example of how species that haven't been desirable in the past really produce some beautiful building material," said foundation spokesman Craig Maier.

Much of the lumber for the center came from "Charlie's Woods," named after Bradley's late husband. During pre-settlement times, fires would naturally move through oak forests every five or 10 years, sparing the oaks and knocking back less-tolerant species, Maier said.

When workers came through in February 2006 to harvest for the center, it had been 25 years since the woods were thinned, and the trees were densely packed with red maple, black cherry and ash — species that stifled the young oaks.

"By keeping this as an open-oak woodland, we're trying to restore an ecosystem that's becoming less common but adds a lot of diversity to the landscape," Maier said.

The process lent permanence to both the forest and the foundation.

"We're quite excited about the fact that we're using our own wood," Bradley said, "trees that we planted."

The Legacy Center will not replace the Shack, and the Foundation will not market the site on rustic Levee Road in rural Fairfield as a tourist destination, said Executive Director Buddy Huffaker.

"We don't see this building as being an end to itself," he said. "The building was part of this larger effort to position the foundation to have a larger impact in the region and beyond."

The center includes a meeting space with vaulted, trussed ceilings, cherry flooring and earthen plaster walls; a three-season classroom for trips and larger groups; a library; an exhibit hall; and office space for foundation staff members.

The center's $4 million price tag was a major piece of a Land Ethic Campaign to raise $7.5 million, which also covered restoring the Shack, digitizing Leopold archival materials and creating a small endowment to give the foundation financial stability.

Since 2004, the foundation has raised nearly $7.25 million, largely from private donors, Huffaker said — a success he attributes to people wanting to connect their values with a place with historical and sentimental significance.

"Locally and regionally, people are looking for opportunities like this to connect this special place in the world with these individuals and ideas that have national and even international respect and credibility," he said.

"Aldo Leopold's call for humanity to accept its responsibility to live in harmony with the natural world is as important now as it ever was," Huffaker said. "I think our society's beginning to more fully come to grips with what a significant challenge this is, but how important it is to get it right."

Huffaker noted how the center works in concert with what the environment of south-central Wisconsin has to offer.

Windows oriented to the south capture passive solar heat in the winter, and overhangs keep the sun out in the summer. An aqueduct collects runoff water and directs it to a rain garden. Nineteen geothermal wells 220 feet below the ground drive radiant floor heating and cooling.

The center is designed to have its windows open, a feature not intuitive to most commercial buildings.

The center will be 60 percent more efficient than the average building of similar size, Huffaker said, and cost less to run than the old 2,500-square-foot office in downtown Baraboo.

"The design team likes to say that we're kind of on the leading edge, not the bleeding edge," he said. "A lot of this stuff has kind of been done before — but perhaps not in combination like we're doing."

Bradley, who served on the project's building committee, said Leopold himself may not have been able to imagine some of the features his namesake building will hold — but he would have approved.

"I hope the center is going to start working locally, nationally and globally to get people aware and thinking about their relationship to the land and to the resources," she said. "I hope it's going to be a centerpiece."