Secondary succession.
Soon after fire. The 1988 Yellowstone National Park fire burned large areas of forests dominated by lodgepole pines whose cones only open in response to intense heat. The intact soil allows seeds to quickly germinate.		One year after fire. The open space created by the fire allows pioneering herbaceous plants to occupy the former forest. The lodgepole pine seeds released by the fire eventually allows the forest to be rejuvenated in a process called secondary succession.