Kill
There's treasure in this tree so you take out your weapon and kill it.
You didn't just cut the tree down, you stabbed it and sliced it and killed it to death.
さつ, さい
ころ
None
But after the kill, Satsuki (さつ) appears and yells at you. She likes trees — remember how she protected one in the 札 mnemonic? — so Satsuki's pretty upset you'd kill one like that.
Here's that little girl Satsuki again. Remember how you imagined her last time? Try to have a picture of her in your mind so these さつ kanji are easier to remember.