Forest Floor

a layer of organic residues on the soil surface of a forest; humus. The forest floor is formed by the decomposition of organic matter (leaves, coniferous needles, small twigs, and fallen bark, for example). It merges gradually with the humus-accumulative (sod) layer, but sometimes it lies directly on the podzol horizon of the soil.

The forest floor greatly affects processes in the soil and forest development because plant nutrients are concentrated in it and because the humus formed acts on the soil layers below it. It also prevents soil erosion and mechanical compaction. The water and air regime and forest-growing properties depend on the forest floor. A variety of organisms inhabit the forest floor: insects, including species harmful to crops and stands, protozoans, fungi, and bacteria.