1. Near the forbidden Forest around couple of enemies
2. 2 near the encampment
3. 3 in the middle of the planes also has those shaded enemies
4. Violent Banyan has 4 and will require navigation through the caverns
5 5 more chests can be obtained by doing the When the Forest No Longer Dim Quest
6. After the quest you can unlock six more by wandering around Giant Banyan and doing its activities.
7. 7 more from the Shooting Party Quest
8. and finally 8 and 9 more from the No response tonight and Danger!Explosive Quest
Hope this helps