Take a walk in the ancient forests of the Pacific Northwest and you will probably come across trees literally growing on trees. It seems that fallen and decaying trees can sometimes provide resources such as these in greater abundance than does the forest floor, so they are preferred germination areas for new trees and shrubs. Once germinated, the seedlings find that these logs continue to provide a favorable substrate for further growth. They call such logs nurse logs. Decaying wood is a good substrate for growth. trees that are hundreds of years old will take hundreds of years to decay. This means that nurse logs formed by old trees will remain available as a substrate for growth for all those hundreds of years, and the new generation of trees will already be old before their nurse logs vanish into the soil of the forest floor. Photographed at the Jedediah Smith Redwoods State Park. Photograph Copyright Francesca Scalpi