Kousuke Ueki

Ability: Change trash into trees
Ability Level 2:

According to a short profile of the main characters of The Law of Ueki (published in the end of manga vol. 16 by the author), Ueki's hobbies include cleaning up his town. In the first volume of the manga, Ueki is seen planting trees in the town park. Despite his power to change trash into trees may look weak in the eyes of others, it is actually quite different from other powers. Other power-users only have the ability to change item A to item B; for example from beads to bombs and from water to fire. But Ueki's power is different in the sense when he changes trash into trees, part of the tree can become trash, which he can change into trees again. In other words, it is a repeatable cycle.