Three years ago, Madison Paper Industries locked the doors of its mill, putting more than 200 people out of work. It was the latest in a long string of mill closures that made Maine’s economic future look dark.

But next year the Madison mill building is scheduled to reopen — not to make paper but a new product that has never been manufactured in the United States.

This month GO Lab Inc., a Belfast-based company, finalized a deal that will allow it to manufacture insulation products out of wood fiber. GO Lab President Josh Henry projects that the company will be hiring about 125 people, giving new life to an old mill town.

The revival of manufacturing is not just good news for Madison or Somerset County. It’s a sign that the next generation of forest products is coming off the drawing board and into production. That’s good news for the whole Maine economy — and since the sustainable forest collects greenhouse gases and stores them, it’s good news for the global climate as well.

Not long before GO Lab acquired the mill building, another company, Advanced Infrastructure Technologies of Brewer, announced that it would be making wood-fiber composite bridge supports that will take the place of concrete in the construction of the new Grist Mill bridge in Hampden. This new construction material is just as strong as steel or concrete, but it’s much lighter and takes less time to install. That’s why they call it “The 72-Hour Bridge,” and the company says that reduced construction time will make wood-fiber composite the lowest-cost option in many projects.

Using wood fiber for insulation, or laminating it into struts and support beams, has been seen for a while as Maine’s future. To see two of these products leave the lab and enter the marketplace at the same time shows how innovation will bring Maine’s economy to a place where forest products are not just lumber and paper.

New products like these make the Maine forest more valuable, which is crucial to fighting global warming. Trees suck greenhouse gas out of the air and store the carbon in their wood. That makes forests critically important, but all over the world, they are being bulldozed for short-term economic gain. A robust market for sustainably harvested timber staves off development pressure.

This can’t happen without innovation, which needs to be fostered by institutions like the University of Maine (where the bridge supports were first conceived and tested) and the Maine Technology Institute, as well as entrepreneurs with access to capital who want to bring new products to consumers.

The future of Maine’s forest products industry may not be here yet, but we are starting to get a good idea of what it will look like.