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The Tree Stumps are two scraps found in Paper Mario: Sticker Star. Mario is required to retrieve them both in different locations: one is on the middle-left edge of the central island in Loop Loop River, and the other is in Tree Branch Trail at the at the top of a high platform right near the start of the level.
Both Tree Stumps must be placed onto the empty spaces with Comet Pieces in Wiggler's Tree House; the Tree Stump from Loop Loop River leads to Rustle Burrow, whilst the Tree Stump from Tree Branch Trail leads to Gauntlet Pond.