Interaction between mountain pine beetle-caused tree mortality and fire behavior in subalpine whitebark pine forests, eastern Sierra Nevada, CA; Retrospective observationsAuthor(s): Constance I Millar; Diane L. Delany
Source: Forest Ecology and Management. 447: 195-202
Publication Series: Scientific Journal (JRNL)
Station: Pacific Southwest Research Station
View PDF (5.0 MB)
The 1351 ha Walker Fire burned in late August 2015 on the eastern Sierra Nevada, California escarpment from sagebrush steppe and pinyon pine woodlands (2150 m) through mid-elevation forests into subalpine whitebark pine (WBP; 3310 m). Fuels were particularly dry due not only to the season but as a result of a record multi-year drought (2012–2015). The fire burned into stands heavily impacted by a mountain pine beetle outbreak (MPB) during a prior drought (2007–2010). Using plot data, we report 100% mortality due to fire of understory vegetation and trees in pinyon pine, aspen, white fir, and lodgepole pine forest types. Fire-caused tree mortality was lower in Jeffrey pine forests (80%), although 100% of the understory was killed by the fire. For WBP plots in areas that had not been affected by MPB, 100% of understory and tree layers also burned. Where the fire burned through plots within the former MPB-outbreak area, 2 of 15 plots had 100% understory vegetation and trees burned by the fire, while the remaining 13 had varying levels of survivorship. In those plots, pines dead from prior beetle-kill as well as live trees remained unburned, as did understory vegetation. Whereas such "gray-stage" stands have been found to reduce fire severity in other regions and forest types, the observed reduction of surface fire was unexpected. In that fires in the subalpine WBP zone and bark beetle-fire interactions have not been studied in California, these preliminary observations suggest that subalpine forests are vulnerable to fire where continuous fuels exist below them. However, in xeric, Mediterranean landscapes, MPB outbreaks in WBP may reduce subsequent burn severity in unexpected ways. These findings may be important given current concerns for WBP’s rangewide vulnerability.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationMillar, Constance I.; Delany, Diane L. 2019. Interaction between mountain pine beetle-caused tree mortality and fire behavior in subalpine whitebark pine forests, eastern Sierra Nevada, CA; Retrospective observations. Forest Ecology and Management. 447: 195-202. https://doi.org/10.1016/j.foreco.2019.05.052.
- Forest changes since Euro-American settlement and ecosystem restoration in the Lake Tahoe Basin, USA
- Evaluation of a post-fire tree mortality model for western US conifers
- Effects of fire and fire surrogate treatments on bark beetle-caused tree mortality in the Southern Cascades, California
XML: View XML