Yeah, I can see some mistakes.
Your big tree takes up a width of 5 tiles. I'm not sure why you've made it do that - is it so you only need to set one tile at the trunk as impassable instead of two? If you don't really care about that, you're better off moving it over so it only takes up 4 tiles in width. Otherwise, if you leave it as-is, you need to move that trunk with flowers away from the top corner and leave that tile blank.
If you keep it with a 5-tile width and leave that trunk with flowers there, every time you want to use that tree, you're going to have to place it in two stages. Or you can place the whole thing and then you'll have to remove that trunk/flowers tile. Either way it's an extra step that you'll have to make over and over and over, when making a quick little change now can avoid it. All those tiles the width and height of the tree should be empty. There's an empty spot at the end of the row above where you could put the trunk/flowers.
Also, all of those tree trunks with the different mosses, don't go right to the top of the tile. You should copy the leaves from the big tree and put those in. Otherwise, you'll put the big tree on the middle level. If you then take a trunk with moss and put IT on the middle level, you'll be losing the leaves that should be above it. You COULD put it on the top level instead, but that's wasting a level and I'm all for conservation
I don't see any other problems with it though.