SWAN VALLEY — The largest land conservation deal in U.S. history closed last week as Plum Creek Timber Co. announced the sale of nearly 70,000 acres of land in the Swan and Blackfoot Valleys to the Nature Conservancy for $89 million.

The Trust For Public Lands was also involved in the fundraising effort called the Montana Legacy Project, the deal marks the final phase of the project and includes 24,208 acres in the Clearwater River drainage, 24,506 acres near Mill Creek and 20,809 acres in the Swan Valley. Since the project began in 2008, 310,585 acres of land in the Swan, Blackfoot and Lolo regions have been protected. About 112,000 acres of lands have already been purchased by the U.S. Forest Service. Montana Fish, Wildlife and Parks recently purchased almost 14,000 acres and a bought a conservation easement on 9,348 acres for $14.8 million. The state of Montana has bought the remainder.

After the final transaction, the Conservancy has about 112,000 acres left to sell. Plum Creek’s land ownership in the region was largely in a “checkerboard” pattern and interspersed with existing public lands. Over the years, Plum Creek had started selling off some of its holdings to developers in real estate deals it called “higher and better” use. Problem was, some of those land deals conflicted with wildlife corridors and conservation efforts in the region. The valleys are home to grizzly and black bears, lynx and bull trout.

“We recognize these lands have ecological, recreational and timber production values and we were pleased to partner once again with The Nature Conservancy and The Trust for Public Land to accommodate the public interest in conserving special lands in the state,” Tom Ray, vice president of Northwest Resources and Manufacturing for Plum Creek, said.

A fiber supply agreement ensures continued harvesting on these lands to Plum Creek mills for up to 15 years from the close of the first phase of the project in 2008. Plum Creek purchases the timber at fair market value. After the fiber supply agreement expires, other mills would have the opportunity to access timber from the lands.

Even after the sale, Plum Creek still owns about 900,000 acres of land in Montana. The idea behind this effort is to keep large tracts of land intact through public ownership. The lands will be open to timber harvest and traditional uses such as hunting and fishing, but not subdivided for housing and other land developments. Conservancy spokeswoman Bebe Crouse said the plan is to place nearly all the lands in public ownership as funds become available.

“The Montana Legacy Project not only preserves habitat for wildlife, it ensures that people are still able to use this land for recreation, as a source of clean water and as a place to make a living through activities such as ranching and sustainable forestry,” Kat Imhoff, state director of the Montana Chapter of The Nature Conservancy, said.