英語聽力：自然百科 Fighting Fire with Fire 以火攻火 保護(hù)森林

It's been protected from human impact since 1909. With three million acres, nearly a half million under water, Superior National Forest is largely unspoiled. But now the survival of this national treasure rest with those who would see some of it burned. When a massive windstorm flattened nearly a half million acres of trees in July of 1999, the Forest Service knew a major wildfire wasinevitable. They refer to this area simply as ‘the blowdown’, over 700 square miles ofkindling just waiting for a spark.

"Yeah, we are kind of wondering why that hasn't happened, um, when it's twice as dry, twice as warm and windy and there is lightning out there. But, er, so far we just haven't had lightning in a good patch of timber to burn." On this day," just to let you know the Magnetic Rock burn is a goal."

The Forest Service will strike the match. "The weather forecast for today is favorable". But not before checking that conditions are just right. "Pretty consistent, mainly southwest to leave at 14:50."

Gusts of wind more than 15 miles per hour in the wrong direction could be disastrous. And if things go wrong, if the fire gets out of control, it would be burn boss Tim Norman who's responsible. "Yeah, Tim, we're ready to launch the torch of fuel". It will come from above. The helicopter disappearing over this ridge will drop a flaming gel on the forest floor. The natural fuel there does the rest. For hours, wave after wave of air assaults rein fire from above. This is the time when all that planning to keep homeowners safe is put to the test.

"Before the burn, during the burn and after the burn, we're trying to look at it as many angles as we can, we're trying (to) outguess what could possibly happen and conduct it safely." In the end, a plan with promise gave way to some disappointment. No safety problems, but the Forest Service had hoped to burn 1300 acres, shifting winds and problems with the flaming gel limited the burn to just 200. But that is still a significant amount of forest to burn.

"How long will this area take to green up?" "Oh, it'll be green by next spring". This area now creates a much needed buffer between the blowdown and hundreds of homes and businesses on the edge of the wilderness .Burning the forest to keep a future wildfire in check. It's a huge job that's only just begun.