Steve Tatko squatted next to the cut end of a red spruce trunk lying in a stack with other felled trees. Eight inches in diameter, its bark was a deep red-brown. Its center held tiny rings of varying widths, pale yellow alternating with a rich sienna. Tatko pointed to some narrow rings only a half inch from the center. 

“It’s possible this tree was seventy-five years old when these were formed,” he said. “And see this thinning?” He indicated an area where the rings squeezed tightly together. “That would have been the spruce budworm outbreak.”

Tatko oversees land management and forestry operations for the Appalachian Mountain Club in Maine, including its timber management project in the contiguous Piscataquis County forest it calls the 100-Mile Wilderness. 

On a cloudy late January day, he was walking through a grove by the headwaters of the Pleasant River’s west branch, off the old site of the Katahdin Iron Works.

Over the course of several years AMC has systematically restored the river’s channels, which were badly scoured by log drives before the Clean Water Act barred them in the early 1970s. The work included stabilizing shorelines and replacing culverts, all to repair the health of waters that serve as the Atlantic salmon’s most inland spawning grounds.

The biological health of rivers and streams depends on the forests surrounding them, and much of AMC’s holdings were cut hard by previous owners. Those stands grew back so packed with small trees that few can thrive. “We’re cutting the junk now so long after I retire there will be good forests here,” Tatko said. 

The club manages its forests using ecological timbering operations, opening scattered gaps but keeping most of the canopy intact. Tatko nodded approvingly at a grove with lush branches of young red spruce. “Pillows of head-high spruce,” he said. “That’s what you want to see.” 

It’s a step toward a major AMC goal: creating diverse forests that provide excellent wildlife habitat while sequestering and storing copious amounts of carbon from the atmosphere.

Using forests as carbon sinks: a critical way to help ameliorate global climate change, and one that seems custom-made for Maine’s expansive woodlands. But all forests aren’t equal, and many of the Maine woods have been cut so hard that reshaping them for carbon storage will be neither quick nor easy. 

A map of New England’s woodlands on the AMC website shows deep green woodlands with rich carbon storage potential through much of the region. In Maine, though, the forest cover is noticeably younger and thinner.

The latest U.S. Forest Service Forest Inventory and Analysis project estimates that northern Maine’s average carbon stocking is only about 19 metric tons per acre, though the state’s eight southern counties hold stocks averaging 27 tons per acre. Other New England States have an average carbon stocking per acre of between 29 and 35 metric tons. 

The November update to the state’s climate action plan, Maine Won’t Wait, calls for developing new incentives for increasing forest carbon storage throughout the state. To help reach that goal, the report calls for increasing the amount of state land in conservation from 22 percent to 30 percent. But advocates say even that increase won’t be enough: buy-in from private landowners and conservation organizations like AMC will be critical.

Carbon storage

In 2014, AMC sold carbon offsets for the Katahdin Iron Works tract to the Climate Trust, an Oregon-based nonprofit. Funds from the sale have helped finance the club’s continuing forest restoration work.

Two other Maine timberland owners, Baskahegan and The Nature Conservancy, have sold offsets into California’s carbon markets. But so far, many landowners say, there’s not enough financial compensation to be worth tying up forestland for many decades.

Each carbon credit sold equals one metric ton of carbon that is captured or held in woodlands. Trees sequester carbon through photosynthesis and store it in their wood. Forest soils also store carbon, as do wetlands and eelgrass beds in the ocean — blue carbon, it’s called.

Approximately 91 percent of the state’s annual greenhouse gas emissions are being absorbed by forests, according to the state’s climate action plan. But that figure includes offsets by private landowners that have been sold into the California carbon market and others and may not be eligible to be counted in Maine. 

To achieve the state’s goal of becoming net carbon neutral by 2045, the report notes, the state must maintain its standing forests — a heavy lift. Tatko noted that in recent years southern Maine has lost thousands of acres of forest cover, mostly to land conversion — in other words, development. 

In 2023 foresters from the University of Maine, the New England Forestry Foundation and the U.S. Forest Service released a study called Forest Carbon for Commercial Landowners. It concluded that the working forests of northern Maine could be cost-effectively managed to store at least 20 percent more carbon each year without decreasing the level of timber production.

This was considered essential to maintaining regional jobs and the local economy. But there was an additional rationale: Setting lands off-limits to timbering is of no real benefit if forests elsewhere are cut more severely to make up the difference (a factor called leakage). 

A computer assessment of 7.6 million acres of North Woods industrial timberlands showed that it’s possible “at the conceptual level” to keep harvesting timber while maintaining or increasing carbon capture and storage in Maine forests, as well as in the products made from the wood. This last point is key: Once a living tree absorbs carbon from the atmosphere, the carbon stays within its wood, even when the tree is cut and made into saleable goods.

The group’s subsequent work details strategies for developing climate-smart forestry on large timberland holdings, both privately and publicly owned. It stresses the need for managing harvests with pre-commercial thinning, cutting small, low-value trees to give more commercially valuable timber room to thrive.

Tracts that have been cleared should be managed to encourage regrowth by species like sugar maple and yellow birch — and not left to regrow with crowded, low-value trees like gray birch, pin cherry and aspen. Such thinning and management practices aren’t generally used on timberlands, the report notes, because they may delay harvests and temporarily slacken income flow. But in the long run they increase timber value.

The study is aimed at working with 10 timberlands owners in the North Woods who together own 7.3 million acres. The owners fully support cultivating carbon storage on their holdings, says Alec Giffen, senior scientist for NEFF. But thinning must be done in several stages rather than all at once. This process takes more time. Normally “as soon as a tree grows to the point where it’s marketable, they cut it,” Giffen said. 

To help offset the delayed income, NEFF had been approved to receive grant money through a U.S. Department of Agriculture program, funded by the Inflation Reduction Act. Payments were to be provided to participating owners who allow stands to continue maturing. Those grants have been frozen by the Trump administration, but indications are that the money may still be forthcoming, Giffen said. In mid-April, a federal judge ruled that the EPA and other agencies needed to unfreeze IRA grant funds. 

NEFF is also promoting several other strategies to shrink carbon emissions — widely recognized as essential to prevent catastrophic climate change. These include building with wood products instead of concrete and steel, especially in cities. Wood construction provides long-term storage of carbon, Giffen notes.

Building with wood is vital — even while forest resources need to be managed so that overall no more forest cover is lost, he said. Careful selective cutting, rather than clearcutting, is vital to achieve that. Maintaining forest cover is an especially challenging goal given the recent rapid development in Maine.

Potential in small forests

Encouraging smaller woodland owners to practice climate-smart forestry has significant potential. The Maine Woodland Association has a membership of 86,000 owners who manage their holdings on their own.

It’s important to remember that there’s no one-size-fits-all formula for carbon management in woodlands, writes Alexandra Kosiba, a forest ecophysiologist at the University of Vermont. What’s best for each grove depends on its history — although standing forest is always better than cleared land, she writes in a recent four-part series in the magazine Northern Woodlands.

Each woodland has unique characteristics ranging from its soil type and elevation to its exposure to wind, Kosiba writes. Even so, some generalizations can be made. Large trees should be left standing whenever possible, since they sequester and store more carbon. Older trees also provide wildlife habitat and contribute to the biological complexity of forests.

Cultivating a diversity of tree species increases carbon benefits, Kosiba writes. Conifers sequester carbon in winter while deciduous trees stand naked. Trees in full summer leaf can take in more carbon than conifer needles. Encouraging the growth of different trees helps make forests more resistant to diseases.

For woodlots with commercially valuable trees, Kosiba recommends scheduling timber harvests less frequently to allow trees to mature and increase their carbon intake. Before and after cutting, she writes, stands should be carefully managed to ensure successful regeneration. The Maine Forest Service offers landowners free consultations with district foresters on improving the health and vitality of their individual forest stands — which can increase carbon storage.

It’s not known by how much woodlot owners have changed their management styles to favor carbon sequestration and storage, Kosiba wrote in an email. “I am working on a research project (in Vermont) with a graduate student this fall to better understand that question,” she wrote. But shifts in forestry practices generally take some time, she noted, and “forest management often operates on long time scales (10 years plus).” 

With the gathering climate crisis, there’s no time to be lost. 

This story was originally published by The Maine Monitor, a nonprofit civic news organization. To get regular coverage from The Monitor, sign up for a free Monitor newsletter here.