Ash Forest is an end game grind zone. To grind here you need 360dp plus at least to survive. Ash Forest mobs are primarily grinded for two things Deboreka necklace, and the costume piece. The La Orzeca Outfit is a new outfit that can only be obtained by grinding and obtaining a lung. Once the lung has been gained you can turn it into an NPC in exchange for one of the costume pieces. Ash Forest drops the left lung. If you cannot obtain a lung drop you can also get black leaf's. Once 100 leaf's have been obtained you can use them on obtaining a costume piece as well.
Ash Forest is located North of Grana; Grana is located South of Calpheon, the third major city in Black Desert.