I recently adopted a trail with the US Forest Service. In the training they gave, they mentioned there was a 3 day training course available for chainsaw certification. At this point in my life, that's bit too much time for me but it might be worth looking into.
If anyone is interested, they are looking for volunteers for Level 1 trail maintenance (clearing drainages, blowdowns and brushing). I responded to a posting by Giff on this site and ended up adopting a trail. At first, I wasn't sure what I had gotten myself into but I've a ball so far. I highly recommend it.
Glenn
PS: If anyone would like to give me a hand brushing out the North Twin Trail, drop me a PM. It needs a lot of work. Even if you can't help and are on the trail, stop and say hello.