The term eco is thrown around a lot these days, preceding a mind-numbingly long stream of words like -friendly, -chic, -tourism, and the ubiquitous -tote. But rarely do we hear it in conjunction with terrorism, as in eco-terrorism, the subject of Sam Cullman and Marshall Cury’s documentary IF A TREE FALLS, which won the U.S. Documentary Editing Award at Sundance this year.

The film takes a closer look at the Earth Liberation Front (ELF), the radical environmental group that the FBI calls America’s “number one domestic terrorist threat.” ELF’s attack against Oregon’s timber companies in 2001, which set fire to millions of dollars of property, is the largest case of domestic terrorism in the country, but you’ve probably never heard of them (precisely why you should see this film). IF A TREE FALLS focuses on Daniel McGowan, an ELF member and “a working class kid from Queens” who’s now serving life in prison for two arsons. “No one got hurt,” he says. “No one got injured and yet I’m serving life plus 335 years.”

The film poses some thought-provoking questions, like “the old adage that one man’s terrorist is another man’s freedom fighter,” but you really ought to see the “part coming-of-age tale, part cops-and-robbers thriller” for yourself. It made the festival rounds this past weekend at BAMcinemaFest and the Human Rights Watch Film Festival, but you can still catch it this week in NY at the IFC Center and in Eugene, OR at Bijou.

IF A TREE FALLS opens Wednesday, June 22, 2011 at IFC, followed by a Q&A with Cullman and Cury every night until the 25th.