Mor humus

[1] Mor humus consists of evergreen needles and woody debris that litter the forest floor.

[2] Mor humus ranks at the bottom of this scale and is characterized by very slow decomposition and accumulation of plant material.

Because it exists under coniferous forests, the litter is composed primarily of evergreen needles, cones, and sticks or other woody debris.

Through their distinct yellow and white coloration, the fungal hyphae in this horizon are identifiable as cellulose-decomposing fungi which are the primary decomposers of organic matter in mor humus.

Compared to the litter of deciduous forests, evergreen needles have relatively low nutrient content and a much lower pH.

Tannins such as Tannic acid protect trees from insects attacks and infection and reduce soil pH.

The lack of soil fauna and incomplete decomposition results in the accumulation of undecomposed organic matter which gives rise to mor humus and its distinctive fermentation layer.