Saving the Tree Spirit- If you want to save the tree, you’ll need a woman’s remains, a raven’s feather, and a black wild horse. It may sound like a lot but you already have a raven feather from the nest with Johnny, and both the woman's remains and the horse is easy to find. Just leave the cave and follow your marker to find the woman's remains. From there, follow the marker to an open field where you will encounter a pack of wild horses. Slowly approach them and use the Axii sign to tame one of the horses. Ride the horse back to the tree spirit to free the spirit.

If you do this AFTER starting the main quest “Ladies of the Wood”, the tree will free the children at Crookback Bog, which will upset the Crones and spell danger for Gran.

If you do this BEFORE starting “Ladies of the Wood”, the tree will not have made the promise of saving the children. But the tree spirit will be freed and Gran WON'T be in danger. Regardless, the tree will exact revenge on the village of Downwarren.
Note: If this quest is done AFTER starting “Ladies of the Wood” it will have a negative impact when it comes to finding Anna, the Bloody Baron's wife. If the quest is done BEFORE “Ladies of the Wood” Anna won't be in the same kind of danger.

Killing the Tree Spirit- If you choose to kill the tree, the tree will put up a shield and summon three endreagas that attack. Kill the giant bugs and then wail on the tree spirit. It will put its defense back up. Repeat one more time to kill the tree spirit. The Crones will be satisfied, which is good for Gran and the village of Downwarren, but not for the children.
Note: This decision will affect the outcome when it comes to finding the Bloody Baron's wife, Anna, in a positive way.