The Acorn is an item that is dropped when cutting down Trees. For every leaf bush on a Tree, there is a chance to get one Acorn, and the chance is highest with the leaf bush at the top. However, cutting off a branch with a leaf bush on it will always give you one Acorn. Acorns can be planted and will eventually grow into Trees. If you have played on a single world for a long time and have cut down all the trees, it is advised to stockpile these.
A newly grown sapling, sprouting from its acorn.
Notes
When planting Acorns, remember to leave them enough space for them to grow, 3 blocks each is enough.
Saplings will not grow above ground if there is a Dirt Wall behind them.
The saplings can be destroyed by hitting the block they are planted on (or the sapling itself) with a pickaxe. Doing this will not drop an Acorn.
Planted Trees have a maximum height of 14 blocks. They will not grow as high as some of the very large Trees the player may see, which are automatically spawned by the world itself.
The size and shape of the resultant tree is random, and permanent. Trees do not continually grow.
Removing the weeds around the sapling may improve the growing speed of the Tree.
