As devastating as it may appear, fire is a natural process, and Joshua Tree National Park has endured centuries of lightning-caused fires. Although fire in deserts has been less common than in forests because shrubs and trees are widely spaced in deserts and grasses not as abundant as in wetter areas.
The park maintains records of fires dating back to 1945. Most of these fires occurred between May 18 and September 20 when desert vegetation was very dry. Seventy-four percent of the fires were ignited by lightning. The remaining 26 percent were human caused. The number and intensity of lightning fires has increased over the past 50 years. Before 1965 most lightning fires burned less than one-quarter acre. After 1965 more large fires and more frequent fires have been recorded. In 1979 the Quail Mountain fire burned 6000 acres; in 1995 the Covington fire burned 5158 acres. And in 1999, the largest fire in Joshua Tree's history, the Juniper Complex fire burned 13,894 acres of slow-growing California junipers, pinyon pines, and Joshua trees. Exotic grasses, such as red brome and cheatgrass, now represent up to 60 percent of the biomass from annuals.
Resource managers believe the increased fuel loads provided by these exotic grasses are responsible for carrying lightning-ignited fires from plant to plant. Desert plants do not need fire to reproduce and most are highly susceptible to fire. Shallow roots are easily burned and seeds lying on the ground waiting to germinate are destroyed. The desert does grow back but recovery after a fire is slow. Joshua trees can live for hundreds of years, and if one burns, it will take a hundred years for another to take its place. Even small shrubs like blackbrush may require 50 years to return to a burned area. Non-native grasses are also able to quickly recover after a fire and are usurping the habitat of native grasses.
The key to managing fire in Joshua Tree is in understanding how wildfires affect vegetation and wildlife in a desert environment where non-native grasses may have substantially altered the local ecology. Biologists are monitoring the long-term consequences of these newly arrived plants. To help preserve and protect wildlife, scenery, and natural processes, each park develops its own Fire Management Plan. At Joshua Tree, we are revising our plan to provide for full suppression of all fires, including those naturally caused, until we have a better understanding of fire behavior and effects in the park. Although fire plays a beneficial, even a critical role, in some ecosystems, that may not be the case at Joshua Tree under these new conditions.