Tree

Trees are the only source of Wood in the game and they exist in the Forest Biome. Cutting down a tree using an Axe will always give you some Wood and sometimes Acorns. All trees essentially have the same width, but their height can vary quite a bit.

It is advisable to cut trees at their lowest piece, the trunk. If you do not cut at the trunk, only the Wood above and where you are cutting will drop. Also, cutting the sides of the trunk, the roots, will not cut down the whole tree, but rather only that part. Trees will not grow back if they have been cut down and do not grow larger over time.

When cutting down a tree, the amount of Wood you get is based on how high the tree is, and how many branches and roots the tree has. For every leaf bush on a tree, there is a chance to get 1 Acorn, and the chance is highest with the leaf bush at the top. Cutting off a branch with a leaf bush on it will always give you 1 acorn, while cutting off a branch without a leaf bush on it will give you 1 Wood.

When The Corruption reaches a tree, the tree's leaves will change to a purple color and it will become corrupt. Corrupt trees drop normal Wood and Acorns and differs from a normal tree only by color. (Acorns can't be planted in corrupted areas, though the Corruption may spread underneath the tree, causing it to change color.)

You may only place acorns on grassy areas with no plants (flowers, extra grass, etc). You can chop down all excessive green by swinging most weapons. If you are planning to plant a great number of trees, consider making a horizontal line of dirt, so it would be easy to run and swing weapons, effectively mowing down unneeded grass.

Trees planted by the player can grow to a maximum of 14 tiles high. Saplings have the following requirements to become trees:
 * 1) The sapling's lower tile must have no wall
 * 2) There must be a tile of grass to the immediate left and immediate right of the grass the sapling is planted on
 * 3) There can be no trees less than three tiles away
 * 4) The sapling must not currently be in view on the screen

You can't grow a tree at the edge of a step or cliff, next to a step or cliff, or at the edge of a patch of grass, even though you can plant acorns there. While trees can, very rarely, grow a distance of three tiles apart (two empty columns between them), they grow much faster at a distance of four tiles apart (with three empty spaces between them). For these reasons, it is recommended to plant acorns every four tiles on a long flat row of surface grass. Tiles more than 14 units above the planted grass do not have any effect on tree growth, so an optimal tree farm can have multiple 15-tile high levels. Unlike many plants, saplings will not grow into trees while they are on the screen; they will only grow when not currently in view.

If you run out of trees and acorns, you can purchase more from the Dryad.

It has been said by the creator himself that if there's one thing in the game you won't run out of, that's wood from trees.(Citation Needed)

You can make overground jungles which automatically spawn trees. The trees will look dark green and have vines all over them. They will drop wood and acorns, so making a jungle for trees is recommended.

Following its growth patterns, a tree farm can easily be made to generate vast amounts of wood. When working with a tree farm, I advise to cut one notch above the stump. This way you will not have to worry about going back to replant acorns as the trees will grow back with just the stump left behind.