DULUTH — A land swap is in the works that would restore some 22,000 acres of swampland in one of Minnesota’s most important bird conservation areas.

A private wetland mitigation company plans to acquire and rehabilitate the land in the Sax-Zim Bog area in St. Louis County to its original, pre-settlement condition, before the land was drained for farming. In exchange, the county and the Minnesota Department of Natural Resources will get thousands of acres of upland forest elsewhere.

The Conservation Fund, one of the nation’s largest land conservation organizations, would buy the forest land from private parties, trade it to the county and DNR for the swampland, then sell the swampland to Ecosystem Investment Partners. The company would then restore the wetlands and recoup its costs by selling credits to developers that are required to replace wetlands lost to construction and other projects. The arrangement is known as a wetland mitigation bank.

“This will be the largest wetland mitigation bank anywhere in the U.S. by several thousand acres,” said Nick Dilks, a managing partner in the Baltimore-based for-profit company.

No price tag has been put on the deal, since the private forest land has yet to be acquired. And it has yet to be determined how many acres of forest will be involved. But those involved say the deal is worth multiple millions of dollars. All sides are working to concluded it by year’s end.

The restored wetlands would be adjacent to, and nearly surrounding, the state’s Sax, Fermoy and Zim Wildlife Management Area complex of about 2,300 acres. That state land already is protected and managed for species like sharp-tail grouse and sandhill crane, said Jeff Hines, assistant state wildlife manager for the area for the DNR.

The restored wetlands would also benefit many plant communities and wildlife like moose, Connecticut warblers, great gray owls, northern harriers and more, Hines said.

“To have those areas that have been ditched restored to something like their original state is going to be a plus for several species,” Hines said. “We know moose are using those boglands to cool off, and spending time on birch and conifer islands in the bogs.”