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Historic frequency and severity of fire in whitebark pine forests of the Cascade Mountain Range, USA

Author(s): Michael P. Murray, Joel Siderius
Year Published: 2018
Description:

Whitebark pine (Pinus albicaulis Engelm.) is a foundation species of high elevation forest ecosystems in the Cascade Mountain Range of Oregon, Washington, and British Columbia. We examined fire evidence on 55 fire history sites located in the Cascade Range. To estimate dates of historic fires we analyzed 57 partial cross-sections from fire-scarred trees plus 700 increment cores. The resulting 101 fire events indicate fire has been a widespread component of Cascadian whitebark pine stands. Results are site specific and vary considerably. Whitebark pine stands appear to burn in a variety of severities and frequencies. Sites where fire intervals were detected ranged from 9 to 314 years, with a median of 49 years, and averaging 67 years. Fire intervals shortened significantly with higher latitudes. In assessing the most recent fire event at each site, overall, 56 percent burned as stand replacing events. In the 20th century, the number of fires diminished significantly. Due to conservation imperatives, re-introducing fire should be undertaken with extreme care to avoid substantial mortality of this endangered species.

Topic(s): Fire Ecology, Fire History, Frequency, Fire Regime, Fire Intensity / Burn Severity
Ecosystem(s): Alpine forest/krummholz, Subalpine wet spruce-fir forest, Subalpine dry spruce-fir forest
Document Type: Book or Chapter or Journal Article
NRFSN number: 16810
Record updated: Sep 18, 2018