ZIM - Ron Ryberg drove the big Marsh Master all-terrain vehicle with a deft touch, through deep ditches and across former cropland and sod fields that are slowly soaking up water.

It's here where crews are using whole tamarack trees and mud to plug ditches and slow the flow of water across the land - recreating the peat bog that covered the land for millennia before it was ditched and drained in a failed attempt to make farmland

"Once you plug the ditch it doesn't take long here and things get pretty wet," said Ryberg, who's lived just up the road in Forbes for 50 years now. "Some people around here are afraid of what they're doing here. But I think it makes sense ... Why the heck anyone tried to farm here is beyond me."

The 'they' is Ecosystem Investment Partners, or EIP, the Baltimore-based for-profit company that has acquired 23,223 acres, 36 square miles of the Sax-Zim bog area to restore as naturally functioning wetlands.

The restored wetlands would benefit many plant communities and wildlife such as moose, Connecticut warblers, great gray owls, northern harriers and more, wildlife experts say.

The company then plans to sell credits for those restored wetlands to developers, highway agencies, mining companies and others who are forced to destroy wetland to complete their projects.

It's the first such wetland mitigation bank anywhere in Minnesota's Lake Superior watershed, and it's the largest active restoration wetland bank in the U.S.

The project initially has some opposition, with critics saying the new wetland bank will make it easier for proposed mining and development projects to gain regulatory approval for destroying wetlands while doing little to improve the environment.

But supporters say the project is long overdue - that it's past time that wetland mitigation efforts for local projects are in fact mitigated in the region and not across the state. The development will happen, supporters note, so the benefits of wetland replacement might as well be close by.

The project, first reported in the News Tribune in 2013, was made possible after a complicated land deal in which EIP traded forested land that it purchased from Potlatch to the county in exchange for thousands of acres of old peat bog here - so-called tax forfeited land that has been under the county's care for decades, after farmers failed to make a go of it.

EIP also acquired 11,500 acres of land from the state and more than 3,600 acres from private landowners.

EIP will pay taxes the land, the first time that's happened in decades. And the habitat restoration aspects have received strong support from birders who have made the Sax-Zim area a globally popular birding destination.

"This project is good for the economy. It's good for the county. And it's good for the environment," said Nick Dilks, a founder and managing partner at EIP. "We're going to supply high quality wetland mitigation for projects in St. Louis County and across northeastern Minnesota."

County officials worked with the nonprofit Conservation Fund to broker the deal to allow for more development and get more land on the tax rolls. But St. Louis County Commissioner Keith Nelson of nearby Fayal Township said the project also benefits the bog itself.

"The highest and best use of this property is what's happening right here today," Nelson said at a grand-opening event Wednesday marking the start of restoration work at the site.

The project received U.S. Army Corps of Engineers approval last month.

Much of the bog - dominated by low-lying tamarack and black spruce - was originally cleared and ditched starting in 1915 and into the 1930s. But most of the land never produced much. While some people called it progress at the time the ditches were dug, "today is the real progress because it's being put back the way it should be," Nelson said.

The Sax-Zim project is the second for EIP in Minnesota. In 2012, EIP developed the Mississippi Wetland Mitigation Bank in Aitkin and Itasca counties, also in peat-bog terrain.

Murray Starkel, project manager for EIP, said the company could start selling credits for the Sax-Zim project later this year or early in 2016. But the company won't get approval to sell credits until the wetlands are actually restored and signed-off by regulatory agencies like the U.S. Army Corps of Engineers and Minnesota Department of Natural Resources.

The appraised value of the land in just the county portion of the deal was $3.2 million. EIP won't disclose how much money it has invested in the overall project but said it hopes to turn a profit by selling credits at a premium, noting regulatory agencies prefer to see developers replace wetlands as close to projects - like new mines - as possible.

"There are a few remnants of natural fens out there that offer a glimpse of what this should look like here," said Steve Hobbs, Minnesota director of the Conservation Fund. "The goal is to see it looks like that as much as possible."