Trees and shrubs that lose their leaves are called deciduous trees. Deciduous plants have broad leaves that fall off when the plant goes into a dormant state, usually in the winter. Some plants are deciduous where there is a dry season.
Evergreen trees are trees that keep functional leaves year-round. The leaves of evergreens are typically needle-like as opposed to the broad leaves of deciduous trees. The needle shape requires less water to maintain, making it possible for the plant to keep the leaves even in the colder, drier months of winter. Some broadleaf plants, such as eucalyptus, are also evergreen, but these are all tropical plants.