Petalburg Woods
From Bulbapedia, the community-driven Pokémon encyclopedia.
Petalburg Woods is a forest in Hoenn, the land in which the games Pokémon Ruby, Pokémon Sapphire, and Pokémon Emerald take place. It connects Petalburg City to Rustboro City.
In Ruby and Sapphire, the first time your character goes through Petalburg Woods, he or she is attacked by a member of Team Aqua/Team Magma. The member intends to steal some papers from a man in the woods. The man turns to your character for help, and you battle the member and his Lv. 9 Poochyena. After you beat the member, the man will thank you with by giving you a Great Ball.