nurse log
A fallen tree that serves as a seedbed and nutrient source for new growth — mosses, ferns, fungi, and the seedlings of trees that will eventually tower above the rotting wood that nourished them. In the Pacific Northwest, rows of mature trees sometimes stand in a perfectly straight line, their roots straddling the ghost of the nurse log that raised them and has since decomposed entirely. The nurse log is the dead that feeds the living.
Etymology
Forestry and ecology term. The log "nurses" the seedlings — an old metaphor for what turns out to be a literal biological relationship.
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