You can plant trees on any empty section of your farm. Trees yield three rounds of crops before withering away. A withered tree can be removed with the help of a saw or an axe. It can also be revived by one of your neighbors.

You can revive a tree by asking your neighbors to help you water it. This will allow you to gather another harvest from the same tree. Four harvests is the limit. After that, the only thing you can do with it is chop it down with an axe, or fell it with a saw.