I have 4, but I only have one butterfly and three heart stumps. Winnie is the only villager who's ever sat on a stump. And I also have the silver axe. (I bought 5 of them because they're really rare and they do break.)
On the sapling trunks I have the ginko leaf and the butterfly, on the pine trees I have a row of them with the cat face, leaf, flower and I believe the music note. I need to do another row of them with saplings like I did pine trees. It'd be easier to check every day.