ANCHORAGE (AP) -- Beneath a swath of forested limestone in Southeast Alaska where the Forest Service is planning a logging operation, are networks of caves that scientists and cave experts say could provide clues to the origins of the region.
A group called the Tongass Cave Project has asked the U.S. Forest Service to reconsider a pending timber sale on Kosciusko Island on the outer coast of the panhandle west of Ketchikan.
The sale in the Tongass National Forest would yield about 26 million board feet of timber, district ranger Dave E. Schmid told the Anchorage Daily News.
The cave project wants the entire area managed as wilderness, where development such as logging and road-building is banned. The group says the topography of the island is too valuable to be damaged.
The caves, also called karst, are created when rain and snow melt away limestone and marble rocks. The dissolved rock results in warrens of caves, underground streams, unearthly ridges and deep sinkholes.
Karst areas of the Tongass have produced a wealth of scientific discoveries over the last couple of decades. Human and animal bones up to 50,000 years old have turned up, as well as insects not thought to exist west of the Rockies, said Steve Lewis, co-director of the Tongass Cave Project and a former Forest Service employee who conducted cave expeditions for the agency.
Bones from animals now extinct in Southeast, such as brown bear, caribou, arctic and red fox, have been pulled out of caves in Southeast, said Jim Baichtal, forest geologist and cave expert with the U.S. Forest Service. The remains of a shaman were found in a sea cave on Kosciusko Island, he said.
The bones have taught scientists, among other things, that not all of Southeast was covered by ice during the Ice Age, Schmid said.
Karst is especially important because Southeast is chronically drenched in rainfall, so most artifacts quickly disintegrate. The caves protect bones, tools, baskets and other finds from the harsh rain forest environment.
Karst also tends to grow especially large trees.
Much of the logging that has taken place in the Southeast rain forest since the 1950s has occurred in low-elevation karst lands, Schmid and others said.
Before foresters came up with modern-day methods of tree cutting, considerable damage was done to the caves, according to the Forest Service. Clear-cut logging removes the forest's canopy cover, which can change the drainage patterns that flow into caves, sometimes clogging them with sediment and other debris.
These days, the Forest Service requires loggers to leave buffers, or no-cut zones, around caves, sinkholes or other obvious features of karst. Agency foresters survey the units with aerial mapping imagery, as well as walking on foot. They try to avoid allowing timber sales in areas that are especially vulnerable, according to the agency. If a cave is found, the Forest Service can stop a logging operation or require additional protections.
Schmid said almost three-quarters of the original Kosciusko timber sale was ruled out because of karst. In the remaining areas where logging will be allowed, cutters will be required to leave at least 30 percent of the forest canopy, both to protect wildlife and karst, he said. That means it won't be clear-cut.
Schmid said the guidelines are adequate to allow some logging while protecting the karst. But cavers disagree.
Lewis said crews from the Tongass Cave Project did their own survey and located twice as many caves and karst features as did the Forest Service. Even with the caves the Forest Service did find, the steps they proposed to protect the underground environment aren't good enough.
The Kosciusko Island timber sale is still in the planning stages. It's not expected to be offered to loggers until next year at the earliest.
Owen Graham, executive director of the Alaska Forest Association, a logging organization, said he's confident the Forest Service guidelines will protect the karst areas.
''The caves are pretty sensitive. We don't want to do anything to disturb them.''
Peninsula Clarion ©2013. All Rights Reserved.