Big tree down on the Green Loop at Brown Mill.  Cuts off the trail in two places where it has a fairly sharp turn.  You can portage up the hill to where the trail comes back around fairly easily.

I understand that people are allowed to cut weeds and remove small branches impeding the trail on their own initiative, but taking a chainsaw and sectioning an entire tree seems like it might be beyond that.  And I didn't have my chainsaw on my bike anyway...