Strange that you mention trail maintenance on bike trails. On the trail I take to/from work I have to deal with the occasional blowdown, including some large trees. There was a huge tree across the path once and I actually biked to work with a full sized bow saw (partially sticking out of my pannier) and I was going at it for a bit until a cop showed up and asked what I was doing... Well I kind of BS'ed him a bit saying I was just making it easier for the lunch crew to go to lunch. It was a short cut to the local deli from where I work which is also how I get home. Well, technically it's state property but the cop kind of said it was OK, so long as I knew that if I hacked off an arm or something that the state might be held liable, but he didn't mind it either way as I was in fact, doing the work for them.
I eventually finished clearing off the debre and biked the rest of the way home. Of course, I didn't have one of those folding bow saws, just this plain ole home depot one.
Jay