This job sounds like a project for a small tractor with front end loader and bucket forks, chain saw, your DR, wire cutters and some chain. Although you don't have the tractor, you may find them for a reasonable day rate at the local rental agencies. Several rental shops in our area offer John Deeres and Kubotas. Even a mini track hoe would help tremendously.
I'd cut manageable sections of the fencing, hook on to it with a chain, and yank the pieces out with the equipment. I'd have my saw ready to cut the trees and other vegetation grown in to the wire, freeing up the works before I pulled the mess out. Then I'd pile and burn, sorting out the fencing after the ashes cooled.
Look on tractorbynet.com and tractorforum.com for many described projects with pics.
If you're like many of us, you'll get the itch and then buy your own tractor. I try to drive mine nearly every day, because I can!
And, keep the tractor out of your pond. I believe Catmandoo and I have some first hand experience with what a pond tractor looks and feels like. :-)
