The non-living litter over the forest soil is one of the most important layers. It consists of undecayed to mostly decayed organic matter, usually leaves, which are broken down into soil by decomposers (microorganisms, insects, earthworms) and exposure to light, wind, and rain. The litter contains many nutrients that are "recycled" in the soil when it is broken down.
Even in a partially decomposed state, litter is an important component of the forest. The partially decayed wood, stems, and leaves are able to store moisture, preventing water loss by evaporation and erosion due to runoff.