Severe fire increasing in Oregon

Press release today from Oregon State University. The first few paragraphs:

As more of the Pacific Northwest burns, severe fires change forest ecology

CORVALLIS, Ore. — Over the last 30 years, the landscape annually affected by forest fires has slowly increased across the Pacific Northwest, and in some regions, severe blazes account for a higher proportion of the area burned than in the past.

As a result, the ecology of some of the region’s forests is changing in unprecedented ways.

Scientists calculated that less than one-half of 1 percent of the region’s forest is subject to fire in any given year. But in a project using satellite imagery and ground-based tree inventories, they also found that, in areas historically dominated by low- and mixed-severity fires, nearly a quarter of the burned landscape was subject to patches of high-severity fires that often exceeded 250 acres in size.

Studies of fires prior to 1900 suggest that severe fires occurred over smaller patches of forest and accounted for a much smaller proportion of the total burned area than they do today.

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4 Comments

  1. Sadly, Oregon State did not provide a link to the actual study.

    This result seems to conflict with other studies reporting no significant trend in area burned, number of fires, or fire severity for the state of Oregon. Law, B.E., Waring, R.H. 2015. Review and synthesis – Carbon implications of current and future effects of drought, fire and management on Pacific Northwest forests. Forest Ecology and Management 355 (2015) 4–14. http://terraweb.forestry.oregonstate.edu/pubs/law.fmec.2015.pdf

    and …

    Ray Davis et al (2015) –

    “… examined the MTBS data for any obvious temporal trends in wildfire severity, but did not detect a strong signal (Figure D-6). Over the course of 25 years, there appears to be a slight increase in the percentage of area burned by low and moderate severity wildfire, and a slight decrease in the percent of area burned in high severity wildfire, although these trends are not statistically significant.

    While several studies have indicated that high severity fires are increasing across the western United States (Westerling et al. 2006, Dillon et al. 2011a, Miller et al. 2012), no such trends were apparent in the observed record within the range of the northern spotted owl (Figure D-6). The observed trends in increasing fire severity in various studies appear to be scale-dependent in that these trends were typically for the western United States as a whole. Much of the observed change is either occurring in other areas besides that are encompassed by the range of the northern spotted owl or becomes apparent only when analyzing a larger area that provides a much larger sample size.”

    Ray Davis et al 2015. RMP Revisions for Western Oregon BLM DEIS. Appendix D – Modeling Wildfires and Fire Severity. http://www.blm.gov/or/plans/rmpswesternoregon/files/draft/RMP_EIS_Volume3_appd.pdf

  2. 2nd law, get out and visit some of the burnt forests and you might think differently.
    I believe that the increase in acreage can be directly linked to the Forest Service fire policies and increased “fire fighting” budget.

  3. Of course, pretending that historical fire suppression has had no impact on acres-burned or fire intensity is…. unfortunate. Today’s studies always seem to exclude human occupation and impacts. Yep, significant science is hard to do! Going back to a pre-human landscape is not…. ahem…. desirable (or even possible) in a human-dominated world.

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