NYT Connections Green Group Hint

I don’t blame you if this visual hint is no help at all. I’d actually argue this group is harder than the next one, because I’ve literally never heard of one of its words in relation to the group name, and I’m guessing you haven’t either.
Maybe this verbal clue will help: All of these things provide shade, and one of them is quite, um, royal
Okay, that last hint was a little obvious. But if you’re still stumped, scroll for your spoilers…
Today’s green group answer is Tree Features, and its words are BARK, CROWN, RINGS, and ROOTS. (Apparently, the “crown” of a tree is another name for its canopy. Insert “the more you know” GIF.)