Passage: In contrast, in 1988, Yellowstone was overdue for a large fire, and, in the exceptionally dry summer, the many smaller "controlled" fires combined. The fires burned discontinuously, leaping from one patch to another, leaving intervening areas untouched. Intense fires swept through some regions, burning everything in their paths. Tens of millions of trees and countless plants were killed by the wildfires, and some regions were left looking blackened and dead. However, more than half of the affected areas were burned by ground fires, which did less damage to hardier tree species. Not long after the fires ended, plant and tree species quickly reestablished themselves, and natural plant regeneration has been highly successful.

Question: What reestablished themselves quickly after the fire ended?
plant and tree species