Somewhere beneath the soft carpet of spruce needles that cover the Tongass National Forest lie secrets that could help unlock the mysteries of humans' first steps in North America. But they are in danger of disappearing.
Last year, scientists discovered 9,800-year-old human remains in a Tongass cave near the Pacific coast, supporting the theory that people migrated from Asia to North America by boat as well as by foot over the now-submerged Bering land bridge. However, such important finds - and the caverns themselves - are at the root of an above-ground dispute that threatens to destroy them.
Some of the biggest trees in the forest grow above the caves, fed by nutrient-rich water that filters through the limestone caverns. Logging companies are eager to tap the bounty, while environmentalists worry that erosion caused by clear-cuts, logging roads, and industrial blasting will irreparably harm the caves.
As both sides take aim at the fertile folds of the rugged Tongass, national forest officials are caught in the middle, pulled between economic issues and untold natural and historic riches.
Start with a plan
Scientists are just beginning to understand what they describe as a "world-class" system of caves spreading throughout the national forest. Geologists and cave experts invited to evaluate the Tongass a few years ago "were pretty much blown away by what they saw," says Jim Baichtal, a Forest Service geologist. "In very few places of the world is karst as a landscape better developed."
To protect karst, the network of porous limestone that honeycombs regions of the vast Tongass, federal law mandates protection of known caves and other karst formations. New cave provisions are also included in the 10-year Tongass Land Management Plan, issued by the Forest Service in May. Officials say they have identified "vulnerable" karst landscapes and tried to keep them free from chain saws.
But so far, no one is happy with this solution. Environmentalists say the protections are inadequate, and timber-industry advocates say they are too tough. Both sides have filed appeals to overturn the Land Management Plan, citing the cave provisions as part of their complaints.
The dispute centers on the 20 percent of known karst that can be logged, but hasn't been. Already, about 40 percent of the Tongass's 500,000 known acres of karst has been logged, Mr. Baichtal says. Another 40 percent is already off-limits to logging because of high altitude, previous wilderness designation, or some other circumstance, he adds.
The new rules in the Land Management Plan set up to protect the remaining fifth are unfair, timber officials say, because they single out logging operations and would diminish south Alaska's prosperity. "They have traded the uncertainty of protection for the certainty of job loss," says Jack Phelps, executive director of the Alaska Forest Association. "If you want to protect some lands because there are important caves, then find some other lands and take the protections off. It's always the timber industry that has to suffer for some other value."
But some members of the industry are more interested in protecting the Tongass's natural heritage. "They should just stop logging on karst," says caver Pete Smith, who lives on Prince of Wales Island and operates a small-scale sawmill there. "There's just not enough of it left to keep destroying it all."
So far, about 500 Tongass caves have been mapped, and new sites are still being discovered, Forest Service officials say.
Since the first major paleontological discoveries in 1990, the caves have become a treasure trove of information. In addition to a 44,500-year-old marmot tooth, scientists have found Indian-style paintings similar to designs still used by local tribes and 10,000-year-old brown-bear bones in a Prince of Wales cave. The bear find was significant because it points to ecological changes since the Ice Age - there are no longer any brown bears on Prince of Wales Island.
Altering the ecosystem?
If logging continues, many say, the ecosystem will continue to change - for the worse. The water that is filtered, purified, and enriched by the limestone supports huge populations of fish and fish-eating wildlife. And when there has been too much logging, says Mr. Smith, scalloped cavern walls are clogged with dirt, and sections once fed by continuous water flows dry up when the timber layer above is removed.
"It's a real delicate balance," he says. "When it's broken, it creates problems ecologically."
There is no question that karst landscapes are fragile, adds Doug Swanston of the Forest Service. "You have to be very careful of where you walk.... You stop and listen to the ground and you can hear water running way down."
For this reason, many are urging caution. "When you look at these areas from the surface, they might not look like much at all, but when you get underneath, they turn into really elaborate networks of chambers," says Tim Bristol of the Southeast Alaska Conservation Council. "You could end up ruining it before you know what's really there."