Unearthing a Frozen Forest

By MICHAEL D. LEMONICK

The massive logs, gnarled stumps and matted leaves lying half buried on the rock-strewn hillside make it clear that a thick forest once stood there, trees that grew 150 ft. high and lived 1,000 years. "You can read the rings -- they look modern, like a lush forest area logged fairly recently," says Paleobotanist James Basinger of the University of Saskatchewan. "But then ) you look around, and you're in a desert. The only trees are dwarf willows one and two inches high." The sparse growth surrounding the half square mile of fallen trees is not surprising: the location is Axel Heiberg Island, less than 700 miles from the North Pole in the Canadian Arctic, an arid, frigid region hardly conducive to the growth of any vegetation, let alone large trees. Then how did a forest thrive? The answer, says Basinger, is that the stumps and logs are 45 million years old, remnants of trees that grew when Axel Heiberg Island -- and the world -- was much warmer.

Despite their great age, the stumps, logs and leaves are astonishingly well preserved. "This fossil forest is not petrified, turned to stone by minerals entering and replacing the wood cell structure," says Neil McMillan, of the Geological Survey of Canada, who discovered a similar but much smaller site 30 years ago on nearby Ellesmere Island. Instead, shallow burial in the Arctic soil has left the forest in a mummified state. As a result, says Basinger, "you can saw the wood. You can burn it." Indeed, during an expedition to the site in July, he actually brewed a pot of tea over burning fossil debris.

The fossil forest should also fuel some important scientific research. "You can see a prehistoric forest in a growth condition: how dense it was, how the trees grew, how productive it was," Basinger says. "It gives us a much better idea of the plants populating the high latitudes (at that time), the kind of environment there, and how they relate to living forms today."

First to spot the fossil forest was Paul Tudge, a helicopter pilot who has been ferrying Geological Survey scientists to and from remote sites on Axel Heiberg and Ellesmere for years. He had once seen McMillan's fossil forest, and on a flight to Axel Heiberg in July 1985, Tudge recalls, "I saw the same sort of stumps, but many, many of them." He later returned to the site, landed nearby, collected samples and brought them to Basinger, who immediately began planning this summer's expedition. Aided by a grant from the Geological Survey and accompanied by another fossil-forest specialist, Jane Francis, from Australia's University of Adelaide, he spent two weeks in July investigating the ancient forest.

The scientists shoveled away soil covering some of the mummified wood, then used brushes to sweep away the remaining dirt so the roots of the ancient stumps would not be damaged. All told, they excavated a dozen stumps to a depth of three feet, identifying some of the trees as dawn redwoods. This species was once widespread throughout high latitudes in North America, Europe and Asia, but is now nearly extinct, surviving in only a few locations in China.

Basinger found that the forest was indeed dense: the stumps are only about ten paces apart, and some are as much as six feet across. "Along the edge of the hill and up on the crest," he says, "are dozens, maybe hundreds of stumps." Basinger also made "an incredible find" -- up to 19 distinct layers of stumps. "Each layer is a forest that developed, lived for many centuries and was overtaken by floods of sediments that killed the roots," he says. "They must have been killed off relatively quickly for the roots not to decay, and buried deeply enough to exclude oxygen but not so deeply as to turn them into coal. That process repeated and repeated itself over several hundreds of thousands of years."

While continental drift has been relocating other land masses over the past 45 million years, Axel Heiberg Island has remained relatively stationary in its Arctic home. The fact that lush forests could have grown so far north indicates that the climate there was once far more hospitable. In fact, scientists have long known that during the early part of the Tertiary period, which began about 65 million years ago, the entire planet was warmer, probably due to carbon dioxide that spewed into the atmosphere during movements of the earth's crust. The result was a greenhouse effect, in which the excess carbon dioxide, like the windows of a greenhouse, trapped the heat of sunlight.

During that period, the Arctic climate resembled that of Northern California today, with one exception: that far north, the sun never sets in summer and never rises in winter. "How did the trees grow so lushly in five months a year of blackness, without photosynthesis?" McMillan wonders. Francis, now back in Australia with samples of wood, leaves and soil from the island, suggests one possibility: "It may be that they shed their leaves and just stood dormant until it became light again, and then grew like mad."

Discovery of the fossil forest may have an economic spin-off. When resins given off by these ancient trees are buried 6,000 ft. underground, according to McMillan, they are eventually converted into very good oil. The resins, he believes, are the major source of oil found in the Beaufort Sea and elsewhere in the Arctic. "The more we know of the climate and vegetation," he says, "the better we'll be able to assess the oil and gas potential there."

But, like Basinger, McMillan is most intrigued by the scientific potential. "There's going to be a generation of work done now in this area," he explains. "When you have so many stumps, when you can see what the forest floor was like, when you have the soil of that time, when you know the angle of the sun giving the months of dark, you have a heck of a lot of facts to work on. We're going to have our fling now."

With reporting by Courtney Tower/Ottawa and Diane Webster/Melbourne