Get one of these - http://www.amazon.com/High-Limb-CS-48-Rope-and-Chain-Saw/dp/B0000AX849
Add extension ropes to both ends. Throw it over the limb you want to drop. Have a helper stand on the opposite side of the tree and play a friendly game of tug of war. You need to be at least as far apart as the limb is high. That way you will cut from the top down and not pinch the saw in the tree. If you try to cut the limb standing directly beneath it like shown in the pics on the package you will pinch the chain because you are cutting into the sides of the limb. If you don't manage to pinch the chain you'll drop the limb on your head. You MUST be at least as far apart as the limb is high.
Add extension ropes to both ends. Throw it over the limb you want to drop. Have a helper stand on the opposite side of the tree and play a friendly game of tug of war. You need to be at least as far apart as the limb is high. That way you will cut from the top down and not pinch the saw in the tree. If you try to cut the limb standing directly beneath it like shown in the pics on the package you will pinch the chain because you are cutting into the sides of the limb. If you don't manage to pinch the chain you'll drop the limb on your head. You MUST be at least as far apart as the limb is high.