If you're running a chainsaw, I strongly recommend Labonville 6-ply full wrap chaps. Take a look at the video and see why.
Chaps test I bought mine for less than $100.00. I feel that it's real cheap insurance.
I've got a small echo arborist saw CS-320? that takes from 12"-16" bar, and a Dolmar 7900 that will take from 24"-36" bar. I can cut good sized trees with the Oregon 32" Reduced Weight bar and a skip chain very quickly. The Dolmar is a 6 hp saw. There's a Silver Maple that is down but not in pieces at the local streets & sanitation yard. They let you in to cut up firewood no charge. I guess it saves them on disposal fees. Nobody's wanted to tackle this one, it's been there for a month and hasn't been touched. IIRC, it's 65" thick at the butt and 42" across where they sectioned it. That'll be fun to try and move around once it's slabbed in 16" pieces!
I agree with PF. If it was my property, and I didn't want to screw around a lot, I'd rent a dozer and make a path as close to the fence as I could without boogering up the fence 1 blade wide. Then use the other equipment that's been mentioned for upkeep.