Plant litter, leaf litter or tree litter is dead plant material, such as leaves, bark, needles, and twigs, that has fallen to the ground. Litter provides habitat for small animals, fungi, and plants, and the material may be used to construct nests. As litter decomposes, nutrients are released to the environment. The portion of the litter that is not readily decomposable is known as humus.
The animals, fungus and bacteria that live in and eat plant litter are called detritivores.