George Alexander, a third-generation mill worker, was just starting his shift at the Louisiana-Pacific lumber mill in Cloverdale, Calif., when the log that would alter his life rolled down his conveyor belt toward a high-speed saw he was working on.

It was May 1987, and Alexander was 23. His job was to split logs. He was nearly three feet away when the log hit his saw and the saw exploded. One half of the blade stuck in the log. The other half hit Alexander in the head, tearing through his safety helmet and face shield. His face was slashed from eye to chin. His teeth were smashed and his jaw was cut in half.

Alexander had never even heard of a sabotage tactic called tree spiking until he became a victim of "eco-terrorism." Someone who objected to tree cutting had imbedded a huge steel spike in the log that violently jammed the saw.

Now the whole timber industry knows, and searching for tree spikes has become a fact of life in lumber mills.

After years of fruitless battles in court and pleas to Congress, some radical environmentalists are using guerrilla warfare to save the woods.

Armed with spikes, bolt cutters and sledgehammers, the growing militant faction is combing the countryside disrupting timber, mining and ranching operations, all in the name of protecting Mother Earth.

Tree spikes are among the most vicious of the strategies. While the tree is still in the forest, the spike is driven in at an angle so the head is hidden in the bark. It can shatter a chain saw on impact, sending pieces of razor-sharp steel flying.

"The purpose of tree spiking is not to hurt anybody; it's to keep trees from being cut," said Dave Foreman, co-founder of Earth First, the most radical arm of the environmental movement.

Since its formation in 1980, Earth First has lived by the slogan "No Compromise in Defense of Mother Earth." Its followers have been known to chain themselves to trees, lie down in front of bulldozers and vandalize machinery. Many Earth First followers don't take part in the eco-sabotage, but the tactics advocated by the group have made it the target of FBI scrutiny. Foreman is awaiting trial on a charge of conspiracy to tear down an electrical tower.

He published a book, "Ecodefense: A Field Guide to Monkeywrenching," and it is an underground best seller. He borrowed the term "monkeywrenching" from the late Edward Abbey, whose book, "The Monkey Wrench Gang," romanticized environmental sabotage.

Foreman's book includes diagrams for tree spiking and instructions on how to cut down power lines, flatten tires, burn machinery, jam locks and set stink bombs. "This is where the ecoteur can have fun," Foreman wrote.

This kind of "fun" brings the radicals into direct conflict with mainstream environmentalists. Eco-saboteurs told our reporter Melinda Maas they think militant tactics will bring quicker results and that the mainstream plodders are selling out. The moderates fear that monkey wrenching sets back the entire environmental movement.