Setting forest fires is one of several terrorism tactics that many people have hesitated to mention because no one wants to give al-Qaeda any ideas.
"One should note that setting fires to forests in the countries of the European Union is a new tendency in al-Qaeda's strategy of a 'thousand cuts'," Alexander Bortnikov said, according to state news agency RIA Novosti, at a meeting of heads of security agencies."This method allows (al-Qaeda) to inflict significant economic and moral damage without serious preliminary preparations, technical equipment or significant expenses."
It's hard to prove arson, and it's hard to catch the arsonists when the fires themselves aren't discovered for a long time after they're started. There's no reason this tactic wouldn't work in America, if it hasn't already and we just don't know it.