You're wrong for both games.

The tree cutting, one random spot on the tree is the "sweet spot". It can be anywhere, the middle, the very top, the very bottom, in between, etc. That's why it shows you where you hit last, because if you hit it and it says you're close, you can try to find the exact spot.

Same for the mining. A random radius circle is the sweet spot. Your job is to find it. It always shows your last attempt as a dark circle so you can experiment and find the spot