Ancient Cedars Hang On

The state’s oldest trees have withstood windstorms, wildfires, and other tests of time.

By John Myers

Helicopters were dropping fire from the sky, and the dead and drying trees on Three Mile Island in Sea Gull Lake were flaming up fast.

More than three years after an unprecedented windstorm downed millions of trees across the Boundary Waters Canoe Area Wilderness, conditions were finally right for lighting a forest fire. On purpose.

Fire experts had predicted since the storm hit on July 4, 1999, that all those dead trees could push wildfires into uncontrollable infernos. So they urged setting dozens of small, controlled fires to rob future wildfires of fuel.

And on this breezy September day, this intentional fire was burning better than expected. The flames were moving fast across the 1,000-acre island, carried along the crowns of red and white pines and chewing up dead wood on the ground. The blaze sent gray-black smoke billowing thousands of feet into the air.

U.S. Forest Service crews were almost giddy. Stymied the previous two autumns by wet or windy weather, they were finally getting a chance to burn—a pre-emptive strike against any fire Mother Nature or a careless camper might spark.

But on the north shore of the island, about 15 USFS and Department of Natural Resources firefighters were making a stand against the very blaze their coworkers had set. They had boated in with portable water pumps and miles of fire hose to save a select few of the island’s trees.

Supremely Old

It’s not that the trees they were trying to save are especially large or stately. But the gnarly, weather-beaten white cedar trees on Three Mile Island are indeed special. Among their ranks and on nearby shores are the oldest living trees in Minnesota. Dozens are nearly 400 years old. Some are more than 600. A few may date back to the time of the Roman Empire.

Lee Frelich, a University of Minnesota ecologist studying Boundary Waters ancient cedars, says it can be tough to tell exactly how old these slow-growing trees are. The rings are so close together that Frelich must rub a tree-core sample with 600-grit sandpaper to pull out enough detail to distinguish the lines under a microscope. On some cores, 1 inch has 100 rings, a century of growth.

Often, when Frelich finds a truly ancient cedar, the inner trunk has rotted, leaving no way to confirm the actual age. "We just need the time to keep looking until we find one that isn’t hollow," he said. "There are cedars up here 1,000 years old and older, I’m sure.’’

An expert on the fire-based ecology of northern Minnesota forests, Frelich has taken keen interest in these ancient cedars. Why are these trees able to thrive where little else can? What allows them to survive fire, disease, and wind when other trees perish? Frelich has been looking for the answers for 11 years.

"They are living biological treasures," Frelich said. "Their makeup has allowed them to withstand the coldest winters, the driest summers, insects, disease, fire. They are the only species I know of that can grow virtually without soil and that can live for 1,000 years in places that burn every 50 or 75 years.’’

Home in the Cedars

That these old cedars are small—usually less than 50 feet tall—and haggard doesn’t make them less valuable ecologically. Frelich notes that old cedars are home to many rare lichens and mosses, some of which grow only on cedars. Cedar forests harbor songbirds, including warblers. Various rare flowers, including some orchids, depend on old cedar forests to grow.

Researchers have found that older trees often have more vibrant seeds and more prolific offspring than younger trees. That makes it even more important to protect pockets of old cedars (and pines) in the Boundary Waters as a seed source to replenish the wilderness after future fires.

"If you planted a million cedars, maybe only one would live to be truly ancient like these," Frelich said. "They have the genetic constitution to survive all of the perils. That makes them very special."

Shore Dwellers

Months before the September fire, Frelich led a team of USFS biologists on a daylong canoe trip to the north shore of Three Mile Island, where he had already identified cedars 600 years old. He knew it would be impossible for crews to save all the cedars on the island and still let the fire do its job. But he believed some of the oldest cedars could and must be saved. USFS officials agreed. It would be Frelich’s job to show them the difference between just plain old and ancient—cedars 400-plus years old.

"Our primary goal with these fires is fuel reduction—protecting life and property along the Gunflint Trail and into Canada,’’ said Bruce Anderson, forest monitoring coordinator for the Superior National Forest, which includes Three Mile Island. "But if we can accomplish that and still protect some of these truly significant resource values, we will.’’

As the group paddled down the lake, Frelich said, "Those are young cedar, just teenagers. Maybe 100 to 150 years old. You can tell by their more symmetrical shape . . . their conical shape on top. And the bark is much less furrowed.’’

At a small rock outcropping halfway down the island, Frelich ordered the party to shore. There, standing alone, a decrepit cedar grew out of the bedrock shoreline. The furrows of the bark cut deeply into its wide trunk. Its limbs, even near the top, were thick. Many branches were dead.

Frelich walked up to the old tree and ran his hands over its bark. "This one here could be the oldest tree in the state. It could be more than 1,000 years old," said Frelich. He motioned to another group of trees down the shore. "Those over there are probably 500 years old."

Hardened by centuries of steady lake winds, these tenacious trees stood firm while many younger pines and other species were snapped off or uprooted by 100–mile-per-hour winds during the July 4 storm.

But these tough, old trees are not numerous. Ancient cedars in northern Minnesota are found mostly in rocky, swampy, remote areas where loggers and fires never quite reached. No formal survey has been conducted, but a few still exist in DNR-managed scientific and natural areas. The famed Witch Tree, clinging to a rocky ledge overlooking Lake Superior near the Grand Portage Ojibwe Reservation, is estimated to be more than 500 years old.

It’s in the Boundary Waters, though, where the most ancient cedars grow in Minnesota. The late forest ecologist Miron (Bud) Heinselman found that nearly half of the Boundary Waters, 400,000 acres, had never been logged. The area sees major wildfires every 50 to 100 years. But being surrounded by water tends to reduce the number and intensity of fires, especially near the shoreline. And it’s islands like Three Mile where most of the old cedars seem to be.

Using tree-ring data, tree scars, and forest species makeup, Heinselman determined that a major fire swept through the Sea Gull Lake area in 1801. But parts of Three Mile Island hadn’t seen fire since 1595, Heinselman discovered. And even the 1595 fire spared some cedars along the shore.

Ancient cedars probably lined more lakes in the region at one time. But lakes that had their levels altered by man-made dams saw the shoreline, and the old trees, flooded. Even in the Boundary Waters, only a few lakes have retained their original water levels and oldest trees.

A Chance to Grow Old

The USFS used information gleaned during the Frelich trip to modify plans for the Three Mile Island fire so flames might avoid as many old cedars as possible. Nearly two–thirds of the island was burned that September day. Crews surveyed nearly 500 cedars after the fire, and early indications are that many were spared, including several ancient trees targeted for protection.

"It looks like about a third of the cedars have no sign of fire—they’re fine. About a third or less were touched by the fire in some manner. And there are about a third of them that we can’t tell yet,’’ said Ann Belleman, a biological technician for the Superior National Forest. "Some of the trees may not have visible damage, but may have been damaged by heat. Or fire may have burned their roots. We won’t be able to tell until this summer or next.’’

The USFS still has tens of thousands of acres to burn over the next few years, finishing a seven-year plan to burn 75,000 acres to reduce downed trees across the wilderness. The agency’s fire experts are learning from their work on Three Mile Island and other intentional fires.

"I think it was a great effort. What they learned there, they can use as they keep burning,’’ said Roy Rich, a University of Minnesota research assistant who is evaluating the recovery of the burn site. "The guys did a heck of a job trying to keep the fire off those cedars. The fire was moving right toward them with all that smoke. . . . When they came in, they were just black from the smoke.’’

One stark revelation was how long the fire continued to smolder and flare up after it was considered out. If crews hadn’t stood by for days after the fire was lit, creeping ground fires on the forest floor—burning through years of old pine needles and dead vegetation—could have killed many more cedars by searing their roots. In most areas, it appears the fire didn’t burn hot enough to destroy the soil, good news for a faster forest recovery.

"It’s going to be a vastly different forest in many places than people will remember from their canoe trips of the past,’’ Rich said.

On the north shore of Three Mile Island, plenty of ancient cedar trees are waiting to drop their seeds and continue their amazing march through the millennia. Belleman, who also joined Frelich’s canoe trip last spring, was happy to report that one tree in particular was saved from the fire.

"The one that Lee showed us, the one he thinks may be the oldest tree in the state. That one was saved for sure,’’ she said. "It’s going to get the chance to get even older."

John Myers lives in Duluth, where he reports on natural resources for the Duluth News Tribune newspaper.

 

Keep the Old

It’s been 164 years since the first commercial saw blade in Minnesota bit into virgin white pine, and several months since 38,000 acres of state-owned forest were designated as protected old growth, not to be harvested as long as they stand. Both moments are historic ones in forest management. The first occurred when half of Minnesota’s forest was ancient; the second, when less than 4 percent was.

Today’s old-growth stands provide a glimpse of how forests grow with no serious disturbance. Old-growth trees (older than 120 years) reach immense size or age. White cedar, with densely packed annual growth rings, can be deceptively small, yet as old as 600 years.

In old-growth forests, mature trees, young trees, dead trees, and fallen limbs weave a complex fabric, nurturing flora and fauna not found in younger forests. Sheltering microsites—downed limbs, trunks, or soil mounds and depressions created by wind-tipped trees —abound on the uneven forest floor. Tree seedlings take root on fallen logs.

"Designating this old growth represents a commitment to acknowledging all the values in a forest, beyond timber harvesting and outdoor recreation," says Brad Moore, DNR assistant commissioner.

Old-growth designation can help maintain biologically healthy forests for the long term. It conserves species, habitats, and rare ecological conditions; and gives base lines to measure change in harvested forests.

The process of setting aside old-growth lands began in 1988 when the DNR old-growth task force formed. In 1994 the first old-growth pine stands were designated, and a group of public, industry, and state agency representatives agreed to goals for preserving old growth.

Later, an inventory of state holdings identified the best stands for designation (including 8,000 acres of younger pine and oak stands, and 4,000 acres of upland white cedar) from 70,000 candidate acres. Nearly all designated stands are in the north woods and southeastern blufflands.

Lee Frelich, old-growth researcher at the University of Minnesota, says the old forests are valuable for forestry research. "These forests are the same vintage as the pyramids . . . the only forests that haven’t had their pattern of adaptation to local climate and soils affected by human disturbance."

Old growth has other values too. Consider outdoorsman Brad Bjorklund’s view: "Things are different in old growth. There is a maturity, stability, a sureness, and a calm that you don’t see in the tallgrass prairie or the immature forest. I hunt squirrels there. Long shots in sound-absorbing silence."

With this historic designation, the values of old-growth forests are now assured a future.

Kim Alan Chapman, principal ecologist, Applied Ecological Resources

Online:

• For more on efforts to reduce fire danger in the BWCAW, go to www.superiornationalforest.org/july4thstorm1999
• For more on cedar trees, go to www.rook.org/earl/bwca/nature/trees/thujaocc.html.
• A report on DNR old-growth policy is available at www.dnr.state.mn.us/forests/oldgrowth.