U.S. Joint Fire Science Program


Date of this Version


Document Type



Fire Science Brief, Issue 3, December 2007


US government work.


Mixed-conifer forests dominated by ponderosa pine trees prevail across the Western United States. Once sustained by frequent, low-intensity fires, these ecosystems have changed dramatically as a result of a hundred years of fire suppression resulting in an accumulation of fuels and shade tolerant species. Researchers are finding that reintroducing fire to these systems may be more complicated than once thought. The forests at Crater Lake National Park are a kind of microcosm for the wide-ranging mixed conifer forests across the West. Early efforts to restore fire at Crater Lake showed that older ponderosa pines were at risk of mortality via increases in bark beetle attacks. In attempts to understand how fire affects tree vulnerability, researchers have gained a new—albeit early— understanding of how pine resin response to prescribed fire may begin to help managers with forest restoration management goals and decisions. The research at Crater Lake offers a deeper, more detailed understanding of how to restore mixed-conifer forests to pre-fire suppression conditions.