Specialised biota, such as molds,[6] produce extracellular enzymes[7] which can easily break down those complex plant polymers(cellulose, lignin and hemicellulose)[8] into biologically accessible forms[9] enriching the soil environment.
[9] Fungal decomposition of a heap of leaves in damp temperate climates can take between one and three years to break down into a dark brown fine powdery humic matter.
[10] A range of micro detritivores are also involved in converting the leaf material into a fine-grained humus, including many isopods, millipedes, earthworms, etc.
In the natural environment, the decomposition of leaves provides a moist growing medium for young plants and protects the ground from drying out during periods of low rainfall.
Leaf mold is not high in nutrient content but is an excellent humic soil conditioner because its structure and moisture retention provide a good growing medium for seedling roots.