Hoo's Wood 2-1
From the Super Mario Wiki
The level starts with a tree, with large mushrooms growing off it that need to be jumped up. To do so, the player needs to activate two ! Blocks that will cause some platforms to appear so they can get to the Warp Pipe. In the top left of the starting area is a Warp Pipe that leads to a room with Sad Nipper Plants and a Red Koopa Paratroopa, at the top of this room is a Toad. The next area starts off with some platforms floating above some waterfalls, though if the player falls off the platforms, they can swim back and start again. After the waterfalls is a platform with a Warp Pipe on it, next to some more platforms with a Warp Pipe above them, if the player goes up the above Warp Pipe they can get coins and unlock some more music. If the player goes through the Warp Pipe on the platform they will go to an area with various enemies before reaching a Warp Pipe that leads to a Toad. The player then needs to go across the platforms to the right of the platform to reach another Warp Pipe that will take them to the next area.