Phoenix trees
Phoenix trees are trees that live on after toppling and that can create new trees from branches of the original with their own roots and everything. They are named after the mythical phoenix, a bird that rises from the ashes to regenerate after death, much like Fawkes from Harry Potter.
In phoenix trees I've seen, a large toppled tree hasn't completely separated from its roots—where some roots are broken as the tree fell, one side of the roots has managed to remain connected. This provides a lifeline for the now horizontal tree.
Remarkably, those branches along the trunk that are now growing upwards can become like trees in their own right and, at times, even put down their own roots. These side trees remain supported by the original great, toppled tree.
Phoenix trees are not to be confused with nurse logs which are dead fallen trees that provide a great environment for new trees and plants to grow in.