Horsepower isn't as important as tractor weight for lift capacities. Assuming you're talking about the tractor in your profile, I got this data for the FEL from Tractordata.com:
Lift to full height (at pin): 700 lbs [317 kg]
Lift to full height (at 500mm): 550 lbs [249 kg]
You can lift more than that if all you're trying to do is get it off the ground and I've heard of a lot of tractors exceeding their ratings. You can also increase the hydraulic pressure to get a bit more lift if you're feeling adventurous. But you should make sure you have a lot of ballast on the rear as counter-weight or you'll stand it up on the front wheels trying to lift heavy.
Green wood weighs 4-5000#/cord. Dry wood is around 3-4000#/cord. So that gives you an idea of what you can do.