Deciduous a. : Falling off, or subject to fall or be shed, at a certain season, or a certain stage or interval of growth, as leaves (except of evergreens) in autumn, or as parts of animals, such as hair, teeth, antlers, etc.; also, shedding leaves or parts at certain seasons, stages, or intervals; as, deciduous trees; the deciduous membrane.

Example:
Why are Deciduous forests poor in species compared to tropical rainforests?

Taxonomy
plants, leaves, deciduous plants, Deciduous forest, leaf, layer, trees, leaf drop, abscission, the leaves, flowers, evergreen foliage, free encyclopedia, woody plants, auxin, growing season, chlorophylls, forests.

Defination from the web:
deciduous means the dropping of a part that is no longer needed, or falling away after its purpose is finished. ... In botany and horticulture, deciduous plants, including trees, shrubs and herbaceous perennials, are those that lose all of their leaves for part ...