Nurse log

Some of the advantages a nurse log offers to a seedling are: water, moss thickness, leaf litter, mycorrhizae, disease protection, nutrients, and sunlight.

Various mechanical and biological processes contribute to the breakdown of lignin in fallen trees, resulting in the formation of niches of increasing size, which tend to fill with forest litter such as soil from spring floods, needles, moss, mushrooms and other flora.

Mosses also can cover the outside of a log, hastening its decay and supporting other species as rooting media and by retaining water.

Small animals such as various squirrels often perch or roost on nurse logs, adding to the litter by food debris and scat.

The oldest nurse log fossils date to the earliest Permian, approximately 300 million years ago.