The Forest Service isn't acknowledging how often the combination of roads and logging causes mudslides, environmentalists say.
That criticism is one of several launched by the Ecology Center, the Clearwater Biodiversity Project and Friends of the Clearwater after the Forest Service issued its final report last week on the slides that devastated the Clearwater National Forest during the winter of 1995-96.
The environmental groups hired a former Forest Service scientist for their own study of the mudslides on the Clearwater forest. The Forest Service is considering whether to impose a nationwide moratorium on building roads in roadless areas across the nation.
Among other things, the Forest Service report failed to consider where both clearcuts and roads were responsible for triggering the approximately 1,000 slides that pummeled the forest, said Bill Haskins of the Ecology Center.
The report also didn't consider how clearcuts may have magnified some slides, he said. If many areas below slides hadn't previously been logged, chances are there would have been trees to slow or stop many of the slides.
The agency didn't tally any slide smaller than 25 cubic yards, said Charles Pezeshki of the Clearwater Biodiversity Project. And the Forest Service relied too much on aerial photos and too little on actually looking at the slides, he said.
"I think they are totally missing the boat," Haskins said. "I find many unsupported conclusions and statements that amount to nothing more than patting themselves on the back for spending $192,000."
But the study commissioned by the environmentalists hardly constitutes proof that the Forest Service's report is incorrect, agency officials said.
"They only looked at a small portion of the forest, yet they say they are able to make detailed criticisms based on their limited data," said Doug McClelland, the Forest Service's regional geotechnical engineer.
As to the criticism of the research methods, the Clearwater Forest is so large that the best way to analyze all of the landslides was using aerial photos, McClelland said. Field crews carefully checked between 40 and 50 of the slides on the ground as a means of calibrating the work of the aerial photo interpretation team.
It was impossible to tally the effects of the smaller slides from aerial photos and it doesn't matter, McClelland said. "No matter how many slides you have smaller than 25 cubic yards, no one would have noticed," McClelland said.
The Forest Service's final report on the Clearwater mudslides isn't totally glowing. Among other things, the agency admits it couldn't conclusively link the age of a road to its likelihood of failure.
Earlier Forest Service officials seemed sure they could say that old roads were bad and new roads were fine. Had that proven true, environmentalists feared it would have encouraged the Forest Service to ignore links between roads and mudslides.
The report does conclude that 58percent of the slides were caused by roads, and suggests five factors that should be used in deciding where it's too risky to build roads. If the suggestions are followed, it may mean fewer roads in the highly erodible area called the breaklands.
"It's going to be pretty hard to economically build roads in those areas," McClelland said.
The Forest Service study also says 108 slides were caused by logging. Environmentalists say they are surprised the agency admitted to that many logging-caused slides - and also say that's a gross underestimate.
Haskins took the Forest Service's data and compared slide areas with past logging. He found 290 slides started where there has been at least some logging, he said.
The Forest Service didn't even try to make that correlation because it doesn't want to implicate the logging program, he said. "They know the road-building era is pretty much over so they can pin the landslides on roads, and put new cutting units next to old roads," Haskins said.
The Clearwater Forest is promising several changes in its roadbuilding program to try to avert another disastrous series of slides. But the agency did a similar study after the 1975-76 slides and it didn't prevent the 1995-96 problems, Pezeshki said.
Indeed, the Forest Service's most recent study concludes that the recent human-caused slides put twice as much mud in the creeks and rivers as did the human-caused slides of the mid-1970s.
