Nurse log

In some forests where the trees grow tall and straight, like those in the US Pacific Northwest, when a giant tree falls, it creates an opening in the forest canopy that lets in light for new growth to take foot. The mighty fallen tree trunks themselves provide a new surface for seedlings to take root, away from the competition of the forest floor. When this happens, the fallen tree becomes an integral part of a new ecosystem.

Such fallen trees are known as nurse logs. Sometimes, a nurse log is so successful as a nursery for the young trees that they will grow along the full length of the fallen trunk. When the original trunk finally decays, it leaves behind it a remarkable, straight line of trees.

Not to be confused with phoenix trees