leaflitter

Leaf litter is the layer of dead plant material that covers the soil surface, consisting mainly of fallen leaves but also including twigs, fruit residues, bark, and other detritus. It forms from leaf drop (abscission) in trees and from shedding after storms or frost; the composition varies with species, season, and habitat. In temperate forests, deciduous species contribute a seasonal pulse of litter, while evergreen and shrub-dominated systems accumulate more continuous inputs.

Decomposition is driven by fungi, bacteria, and detritivores such as mites, collembolans, nematodes, and earthworms. The rate depends on litter quality (lignin and tannins slow decay; nitrogen content and moisture speed it up), climate (temperature and precipitation), and the activity of decomposer communities. As litter breaks down, nutrients are mineralized and incorporated into soil organic matter, supporting plant growth and influencing soil structure and fertility. The litter layer also insulates the soil, regulates moisture, and reduces erosion, while serving as habitat for seeds, fungi, and microfauna.

In streams and other freshwater systems, leaf litter provides an important energy source for aquatic food webs; its decomposition consumes oxygen and supports specialized detritivores. Fire regimes, urbanization, and forest management affect leaf litter accumulation and turnover, with implications for nutrient cycling, soil moisture, and biodiversity. Overall, leaf litter is a key component of forest floor ecosystems, linking aboveground plant communities with belowground processes and broader ecosystem functioning.