Just clearing with hand tools is going to be a slow go. An option, long term, would be to mark out the areas you want to plant and use a herbicide. Using a hatchet or machete you can chop into the bark of the tree and squirt a mixture of Arsenal and water into the chop, the trees will start dying in a couple of months, opening up the canopy, eventually dying. As the limbs fall you can just throw them off to the side. Best would be to get an excavator in there.