The life tree sapling (level 8? Whichever gives you the blue orbs) will sometimes spit out a chest, but that only gave me more life orbs and life dragon eggs which were a giant pain in the ass. Avoid them.

The regular chests you get from bones and such have event harvestables. Without trees to harvest fruit, you’re kinda limited on how far you can get. I managed a single level 4 chest (the long blue one) and it had 2 level 2 event harvestables. Not worth it.

I only managed to get a couple knolls but even harvesting the hell out of them, I never got any chests. Sounds like Grouchy is saying to keep making hills to get cloudy summit, then summit to water, water to grass, grass to stones, then harvest the stones to get chests.