Nurse Log

From Timothy Egan, The Good Rain

In the rain forest, few opportunities are lost; a host of young alders, some as tall as ten feet, have taken root in the slow-dying flank of the snagged tree--a "nurse log," in the terminology of biologists. The seedlings are nurtured on the moss of the nurse log, sucking, searching, probing until gradually the old tree is compost and the new tree is king. Only one of a thousand small trees ever lives to maturity. But when they finally settle in, they're here for centuries

Mixed feelings about this (as a nurse).