Some 500 square miles of privately owned forest in the northern Rocky Mountains will be protected under a deal announced Monday by the Nature Conservancy and Trust for Public Land. The groups will pay Plum Creek Timber $510 million for the checkerboard tracts of land in northwest Montana. The deal is “the largest land purchase, for conservation purposes, in American history,” says Sen. Max Baucus (D-Mont.). The purchase will create a more continuous habitat for wildlife, including grizzly bears, lynx, moose, wolverines, and bull trout, and keep developers at bay; Plum Creek will be allowed to continue sustainable timber harvest in some areas. Baucus was instrumental in the deal, having successfully added a tax-credit bond mechanism to the recently passed farm bill that allows nonprofits to apply for federal grants for conservation land purchases. Half of the $510 million will be available through the Baucus provision, and the rest will be raised through donations.