There are more than a few such groups. Eco terrorists are toward the top of the FBI list for domestic terrorism. Here are some links for you. Some of them are actually Neo-Nazis as well. This is why many neo-Nazis hide in the woods of Idaho. They are greeners - http://www.fbi.gov/news/testimony/the-threat-of-eco-terrorism & http://www.cnsnews.com/node/22327 & http://query.nytimes.com/gst/fullpage.html?res=9B05E2DD163FF930A15750C0A9639C8B63 & http://www.canada.com/news/Neighbours+shot+police+Nazi+environmentalist/2147430/story.html.
Thanks for the info.