After close to a decade as head of Friends of Acadia, Ken Olson plans to retire in February. A search committee is hard at work, culling through 82 applications to succeed him as president and chief executive officer of the nonprofit organization.

He will be hard to replace. Under his leadership, Friends of Acadia has doubled its membership to 3,000, increased its endowment from $4.5 million to $14 million, and become known as one of the foremost national park advocacy groups in the nation. Visitors from other parks have marveled at the close partnership relations between the Friends and Acadia National Park.

Mr. Olson is known for his major part in a 10-year restoration of the park’s 130-mile trail system, now in its sixth year, and for fund-raising successes. These included a $5 million pledge by Mr. and Mrs. Tristram C. Colket Jr. that kicked off the Acadia Trails Forever project and gifts totaling $2.25 million by L.L. Bean to support the Island Explorer bus system on Mount Desert Island.

Always active in preserving the park’s natural beauty, he led the way to an agreement on logging in adjacent areas, to incorporating into the park some 150 privately owned parcels within its boundaries, and further restricting automobile traffic in the park by a projected traffic hub in nearby Trenton.

His part in efforts to preserve the wild nature of the Allagash Wilderness Waterway and the ban on jet skis throughout Mount Desert Island made him a controversial figure to some, but no one doubted where he stood. He once told the Bangor Daily News, “I have the hide of an alligator.”

He traveled frequently to Augusta and Washington, D.C., to represent the Friends of Acadia on state and national issues and kept in close touch with Maine’s congressional delegation.

Less well known has been Mr. Olson’s behind-the-scenes influence in an outraged reaction three years ago to an effort in Washington to bypass the established selection process and grease the way for appointment of a new Acadia park superintendent better known for his political connections than for his experience in conservation and park management. Maine Sens. Olympia Snowe and Susan Collins made pointed inquiries. The selection process got back on track with the eventual appointment of a seasoned professional, Sheridan Steele.

Mr. Olson, at 59, looks forward to future work in the field of conservation and already has received inquiries. But for the next year or more, he plans to take some time off. One possibility, he says, is spending the summer as an “interpretive ranger” in Yellowstone National Park, explaining geology and history to park visitors.

That should increase his knowledge of how the public views the park system. And, incidentally, it could acquaint him further with the running controversy over snowmobiles in the national parks. Yellowstone is where the issue is being fought out. What happens there could set the pattern for Acadia.