Friends of the Norbeck recently commissioned professional statistician Grant Foster to look at possible relations between large fires, on the one hand, and weather, logging, and beetle tree-mortality levels on the other. We provided him with a century of data from the Black Hills National Forest, 1910-2009.
On February 10, 2012, Grant completed his analysis, and produced a detailed "white paper" entitled Pine Beetle Infestation and Fire Risk in the Black Hills (2.7mb pdf, 28 pages).
Grant also posted a more "accessible" (i.e., less mathematical) online version of this analysis at his Climate Blog Open Mind, entitled Pine Beetles and Fire Hazard in the Black Hills, that is available for public comments. Readers are encouraged to read this blog-post on this important Black Hills issue.
Pine Beetle Infestation and
Fire Risk in the Black Hills
However, if a causal relationship [between beetle-killed trees and fire risk] were as extreme as has been often suggested, amounting to a “tinderbox primed for wildﬁre,” then these data would have revealed it. Certainly a relationship cannot be ruled out – but just as certainly, the extremity which has been claimed in public and policy discourse can be ruled out. [p.16, emphasis original]
As far as the data indicate, the greater number of very large ﬁres in recent years is simply due to the greater number of ﬁres. [p. 17]
By no means does this prove that the recent [pine beetle] infestation in the Black Hills is due to warmer wintertime temperature, in fact more than one factor is likely at play. But it is highly suggestive that warming temperature, especially the decline is sustained hard freeze during winter, is an important factor in the dramatic increase in pine beetle populations noted over much of Western North America. [p. 23]
It is our conclusion that there is simply no evidence to support the idea that the massive tree kill due to mountain pine beetle attack has signiﬁcantly enhanced the risk of wildﬁre in the Black Hills National Forest. Wildﬁre hazard is a crucial issue which must be addressed with as clear as possible a perception of the actual risk factors. A focus on pine beetle infestation seems misplaced, threatening to draw attention away from factors which have strong and demonstrable impact on ﬁre hazard and to divert limited resources to less productive strategies. Surely, excessive rhetoric about the urgent ﬁre danger posed by pine beetle infestation, sometimes to the point of hysteria, does not serve the public interest. [p. 24]