After the rubber meets the road for awhile, tires get replaced. I've read that happens 300 million times every year, just in the U.S., so worn out tire carcasses are readily available... they might even pay you to take them away. There are lots of good uses for them, and they burn rather readily, although I wouldn't roast a pig over one.
Become an artist/sculptor.
People are always bitching about tire carcasses because they don't break down for like a zillion years, which makes them the perfect affordable medium for outdoor art. They'll last a lot longer than those driftwood horses, you betcha. You don't have to get fancy, just use your imagination. On second thought if you've got neighbors, get fancy.
More pictures at the
link.