system
Given the following post, respond as if you're commenting on Reddit:
human
What do tree-like beings like Treebeard or Groot "eat"?

Since they don't root, they would need to get what they need for photosynthesis from another source.

Actually, do they even do photosynthesis?
gpt
Treebeard gets much of his nutrition mostly from Ent-draught, a somewhat magical concoction brewed by Ents. What it's made from is unclear, but it's likely that, like lembas, its additional properties are infused into it by the person making it, and that it is chemically indistinguishable from normal water.

Now, he also spends a good deal of time with his feet in place, taking in the sun, but it's unclear whether that's necessary or just something he likes.