By Owen Gleiberman
Updated June 21, 2011 at 04:00 AM EDT

It’s tempting to watch If a Tree Falls doc about a scraggly group of ecoterrorists with a chip of skepticism on your shoulder. Yet the film creates a fantastic moral ambivalence. It was shot after the members of the Earth Liberation Front were arrested by the FBI, and it allows them to explain how, and why, they committed over 100 ”actions” of arson against timber companies, SUV dealerships, and slaughterhouses, mostly in the Northeast. The film sweeps us up like a thriller, forcing us to at least ask whether terrorism like the ELF’s (which targeted property, never human lives) might ever be justified. A