The role of wildfire is an important one for plant and animal species diversity. Many tree species have evolved to mainly germinate after a wildfire. Regions of the park that have experienced wildfire in historical times have greater species diversity after reestablishment than those regions that have not been influenced by fire. Though the Yellowstone fires of 1988 had minimal impact on Grand Teton National Park, studies conducted before and reaffirmed after that event concluded that the suppression of natural wildfires during the middle part of the 20th century decreased plant species diversity and natural regeneration of plant communities. One study conducted 15 years before the 1988 Yellowstone National Park fires concluded that human suppression of wildfire had adversely impacted Aspen tree groves and other forest types. The majority of conifer species in Grand Teton National Park are heavily dependent on wildfire and this is particularly true of the Lodgepole Pine. Though extremely hot canopy or crown fires tend to kill Lodgepole Pine seeds, lower severity surface fires usually result in a higher post wildfire regeneration of this species. In accordance with a better understanding of the role wildfire plays in the environment, the National Park Service and other land management agencies have developed Fire Management Plans which provide a strategy for wildfire management and are expected to best enhance the natural ecosystem.