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Fire Ecology: Fires role on the landscape - bp1

Writer's picture: Rogue SiskiyouRogue Siskiyou

Updated: Apr 11, 2023

A recent analysis of fires from 1985-2010 in Washington and Oregon noted that about half of acres burned during this period did so at a low intensity. The acres that burned at a low intensity were found to have something in common, namely discontinuous fuels. The fuels in these low intensity burns were discontinuous in that from the ground to the canopy, and from tree to tree, there was less connectivity in the fuels than in the areas that burned at high intensity. Another thing the low intensity burn areas had in common was that many areas had received either commercial or non-commercial fuels reduction or thinning treatments. These landscapes historically burned frequently at low intensity, and this analysis gives us hope that forests can be restored to a natural state that is fire resilient and fire inclusive.


Many forests from the Rockies to the west coast are classified as dry mixed conifer, and have a historic fire return interval of around 5-35 years depending on the elevation and forest type. In addition to lightning-caused fires, cultural burning by indigenous peoples was a huge factor in the frequency of fires and influenced the vegetation and wildlife composition and created a landscape that was fire resilient.


Fire return intervals and fire intensity together make up what is called a fire regime. A fire regime is established over time, resulting in a landscape that is heterogeneous with species that are adapted to the local climate and are maintained in their sustainable habitat. A healthy fire regime results in a landscape where most fires burn at an intensity that is “just right” for the species present, maintaining their habitat and excluding or regulating species unsuited for wide spread, long term representation in the occupied ecosystem.

In the West, these natural fire regimes have been absent for over 150 years and more in some places, following the elimination of cultural burning practices. Active fire suppression began in the early 1900’s, and aggressive suppression in 1935 with the introduction of the 10am rule.


Since the exclusion of fire from the landscape a lot has changed. Species that have evolved to be prolific instead of dry climate adapted, such as certain trees and shrubs have spread outside their sustainable habitat growing exponentially in population, while species suited to the landscape have been suppressed or nearly eliminated from the ecosystem in many areas. Many ecosystems currently could be called “unnatural” as fire, a natural element has been excluded for so long unable to fulfill it's role.

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