pry bar for wood deck boards

Why would you use a pry bar to remove SCREWS from a wooden deck? If you were able to get them out it would do all sorts of damage to the wood. Try unscrewing the screws with a nice battery operated screw gun.

The question you ask is a hard one to answer. If you are trying to save the boards your best be is a 24" cats-claw and a block to provide leverage to pry against. If you are not trying to save the boards your easiest way to get the boards off is to cut them about 3" away form the joists and use an SDS drill or wrecking bar. You can strip the wood off the screws and then the screws will come out with ease.