Fire exclusion is the policy of trying to eliminate fires from the landscape using fire suppression techniques (that is, putting fires out when they start).
Fire exclusion has had a diverse and cascading effect on the high elevation landscape. The high elevation white pine ecosystems have evolved with fire and therefore are dependent on fire to maintain their dominance, diversity and presence on sites.
After a disturbance such as a fire, the plant community on the site changes over time, in a process called succession. Plant species that can tolerate the exposed conditions become established first. Over time these species grow and provide shade and protection for other more shade tolerant species to become established on the site. As these shade tolerant species grow, they shade out the species that colonized the site first (the early seral species) and the late - seral species dominate the site until the next disturbance reinitiates the process. High elevation white pines are often the early seral species that establish after a fire. Some of the white pines species have a competitive advantage because their seed are dispersed by Clark 's nutcrackers that can transport seeds long distances to cache them in newly burned areas.
With fire exclusion, many high elevation communities are shifting from early seral, shade intolerant tree species to late seral, shade tolerant species. Without the openings caused by fire there are fewer opportunities for the establishment of the high elevation pines and therefore high elevation white pines become a smaller component of the forest.
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