Trail clearing rehab

My battery powered chainsaw is a problem. When cutting thru thicker wood the chain loosens up and comes off the bar after 5 minutes. I thought 4 weeks ago that I had just 2 trees to clear. 2 weeks ago a storm came through and I had another 4 trees to clear. This afternoon I finally got through one of the problem trees and got to walk the back loop. Another 4 more trees to clear yet. As long as the snow holds off for a couple more weekends I can get this accomplished and xc ski the trails this winter. In carrying the branches off the trails I managed to heavily fall on my left butt twice, luckily not into brambles or rose bushes.  I'm walking with a heavy limp tonight because of that and using vitamin I.  I am using gumshoe boots to walk the trails now. An excellent stroke rehab  boot because it has  no ankle support. 2 hours of walking is great for my ankle muscles and balance.