During the first nine decades of the 20th century, a dozen or so public corporations and private family businesses owned roughly 12 million acres of northern Maine. That’s more than half of the entire state. This land was covered by a boreal forest called, not very imaginatively, the North Woods, and it was a vast industrial woodlot.

Then, around 1990, “the unimaginable happened.” In most environmental stories, ‘the unimaginable’ is something awful, but in Maine it was the opposite. The private owners began selling off their land, and over the next 25 years, from 1990 to 2015, an extraordinary four million acres of the Maine North Woods were entered into some kind of conservation or preservation status.

In a variety of roles, Karin Tilberg was deeply involved in this process, and she is the ideal person to write a history of how it happened.

“Loving the North Woods” begins with five chapters introducing the issues, participants and processes behind this transformation. The next seven chapters describe seven major conservation agreements that together protected some two and a quarter million acres of forest lands. The book finishes with chapters on forest health and a sum-it-all-up conclusion.

There’s a lot of densely packed information here, interspersed with vignettes about the author’s personal history and her connection to the woods. She gives quick descriptions of the people she worked with, uniformly described with terms like “dedicated,” “talented” and “passionate.” And, expectedly in a book focused on legal and bureaucratic activities, readers must wade through a forest of job titles, organization names and acronyms.

For conservationists, this is a remarkable success story, and Tilberg can be justifiably proud of her role in helping it happen. But her account, told entirely from the point of view of preservation and protection groups, glosses over some important limitations to what was actually achieved.

The biggest issue is that the majority of these lands are protected by conservation easements rather than fee ownership allowing ‘forever wild’ management. The easements prevent development, meaning no houses or resorts can be built there. But they allow the landowners to continue using and managing the land for wood production.

The easements also allow continued access for ‘traditional’ recreation, which means ATVs, snowmobiles and existing roads and hunting/fishing camps. Many Mainers feel strongly about such access, and allowing it to continue was a critical factor in negotiating the easements that limited other sorts of development. Still, it’s important to recognize that most of the land Tilberg describes as “protected” is neither in nor reverting to its natural state. It is still industrial forest.

It’s also important to recognize that most of the seven big conservation agreements this book describes involved payments of millions of dollars each to the granting landowners. The easements were not gifts — they were sold. “Loving the North Woods” tells the buyers’ side of the story, but it would be interesting to know what the sellers were thinking. It would take another book to explore that story but scattered through her history, Tilberg gives us enough to ponder. She notes that Reagan-era changes in the tax laws made selling highly appreciated assets like forest land less expensive than it had been before.

Another factor, described in the book’s chapter on forest health, is that the Maine woods went through a devastating spruce budworm infestation in the 1970s and early 1980s. The forest owners had clearcut huge areas of dead or dying trees to salvage what wood they could, and it would take 40 or 50 years for those clearcut forests to re-grow.

So from the landowners’ point of view, this was a perfect time to sell. Great swaths of their land wouldn’t be ready to harvest for half a century. Patient buyers like university endowments and pension funds wanted long-term productive assets, and conservation groups were eager to protect the landscape from being developed. For the forest products businesses that owned the territory, selling development rights on their land wouldn’t deter investment buyers, it would bring in cash, and it would ensure that the land could still be used as working forest. Selling was a no-lose proposition.

Intriguingly, neither the companies nor the conservation groups seem to have imagined what the decline and fall of the newspaper business would mean for Maine’s pulp and paper industry. Newsprint was one of their biggest products, and it won’t be long before that market disappears forever.

Maine’s conservation landscape is changing too. “Loving the North Woods” focuses on what happened during the quarter century from 1990 to 2015. But a new paradigm may be emerging. In 2016 President Obama created the Katahdin Woods and Waters National Monument, protecting 87,000 acres of previously private lands next to Maine’s Baxter State Park. The land was a gift from the founder of the Burt’s Bees corporation, and it is managed by the National Park Service for preservation and recreation. Logging is not allowed.

John Alden has camped on the headwaters of the Allagash and climbed Katahdin, but has most of Maine’s North Woods left to explore.