When battling the Forest Boss, the Dragon, it is possible to dodge him easily. When he burrows, run up against the wall. Chances are he will not hit you. If he does come for you, it is easy to dodge by running left or right against the wall.
This trick is recommended if you are a Force/Hunter, although it might work with a Ranger. First of all, make sure you are at least level 5, with a good MAG (MIND high) so you can learn Resta. If you can get two MAGs (by creating a character, and taking his MAG in two-player mode), it is a good idea to specialize a MAG in the MIND area just so you can learn the techs (Rangers/Hunters), Also, have Dagger/Saber/Cane and Monofluids. Get to the Dragon. Circle around him so that he does not stomp you, and attack his feet. Daggers work best here, as they can do about 30+30 damage. That way, you are safe from his fire. He may fall while you are attacking him. Dodge if needed, but to get the most out of the attacks, get hit, use Resta, and attack again. If he flies, stay underneath him, except when he is landing. After awhile, he will burrow into the ground. If this happens, activate the map to see where he is and try to dodge him. About the second time he does this, he may change direction and try to hit you. You will eventually defeat him. Remember to use Resta when you are weak. As long as you have TP, you will survive. Also, you can try casting Shifta and Deband, Jellen and Zalure. If you have a Varuna (MAG), Kalki or a Vritia, it casts Shifta and Deband for you, even if you do not have it.