deciduue

Deciduous, often misspelled as deciduue, describes plants that shed leaves seasonally. In temperate regions, most trees and many shrubs lose their leaves in autumn as days shorten and temperatures fall. Some tropical species also shed leaves during extended dry seasons, a strategy to conserve water.

Leaf drop occurs through a process called abscission. The leaf’s petiole develops an abscission zone where cells separate and a protective layer forms, allowing the leaf to detach with minimal damage to the branch. Hormonal changes, including reduced auxin and increased ethylene, coordinate this process. Before falling, leaves often change color as chlorophyll degrades, revealing carotenoids and, in some species, anthocyanins.

The ecological function of deciduousness lies in survival and resource management. Shedding reduces transpiration and frost damage in winter or water loss during drought. It also influences nutrient cycling, as fallen leaves decompose and enrich soil. Deciduous forests, with seasonal leaf drop, contrast with evergreen ecosystems where foliage is retained year-round. Some species are semi-deciduous or drought-deciduous, dropping leaves only during particularly dry periods.

In horticulture and forestry, deciduousness affects cultivar selection, pruning schedules, and landscape aesthetics, as well as timber characteristics. Studying leaf phenology—the timing of leaf-out and drop—also provides indicators of climate change impacts.

See also: deciduous forest, evergreen, leaf abscission, phenology.