[Vision2020] "correted" Western U.S. Forest Wildfire Activity

Thu Oct 25 12:31:21 PDT 2007

I accidently sent this before I reviewed it. I frequently hit the wrong key as I am missing one finger. Here is a corrected version. That is not much of an excuse as I am a poor typer to begin with, just makes it worse.
Roger
-----Original message-----
From: lfalen lfalen at turbonet.com
Date: Thu, 25 Oct 2007 12:18:13 -0700
To: "Ted Moffett" starbliss at gmail.com, "Bruce and Jean Livingston" jeanlivingston at turbonet.com
Subject: Re: [Vision2020] Western U.S. Forest Wildfire Activity

> Ted
> Whether published in "Science" or not there are a few things missing. I think that 1934 was hotter than it is now. whether it was dryer or not I don't know. These fire were predominantly the result of arson. The extent of the fires we exacerbated by the dense underbrush that resulted from environmentalist not allowing it to be cleared out.
> Roger
> -----Original message-----
> From: "Ted Moffett" starbliss at gmail.com
> Date: Wed, 24 Oct 2007 13:45:27 -0700
> To: "Bruce and Jean Livingston" jeanlivingston at turbonet.com
> Subject: Re: [Vision2020] Western U.S. Forest Wildfire Activity
> 
> > All-
> > 
> > Regarding the ongoing Southern California fires, and the very important
> > issue of Western US fire potential (especially in Idaho) and causes in
> > general, the following fact and science based sources are critical.
> > 
> > Read about the record drought and heat waves for Southern California (both
> > this year), coupled with the findings from the research on Western USA
> > fires, in the Science magazine article below, co-authored by the scientist,
> > Thomas Swetnam (University of Arizona), who I referenced at the start of
> > this thread, who was interviewed on CBS 60 Minutes last weekend on the
> > subject of wild land fire, with astonishing timing, given the explosion in
> > the Southern California fires that occurred immediately after:
> > 
> > http://www.terradaily.com/reports/Western_US_States_Swelter_Under_Record_Heatwave_999.html
> > 
> > *Parched California has driest 'rainy season' on record*
> > 
> > Los Angeles (AFP) July 1 - Los Angeles suffered through the driest rainy
> > season on record in 2007, marking the least amount of precipitation here in
> > the 130 years
> > 
> > http://www.noaanews.noaa.gov/stories2007/s2838.htm
> > 
> > In Los Angeles, the lack of rainfall led to the driest water-year to date
> > for the city since records began in 1877. From July 1, 2006, through the end
> > of March, downtown Los Angeles had received only 2.47 inches of rain, almost
> > one foot below the normal amount of rainfall for the period.
> > 
> > In the West, where mountain snowpack is relied upon to supply water needs
> > throughout the region, below-average rain and snowfall have become
> > increasingly common. In only two of the past nine years has snowpack on
> > April 1 been at or above the long-term average in at least half the region.
> > --------------
> > 
> > For those who wish to skip most of the Science magazine article, here is a
> > critical finding of their research, indicating human land use is not the
> > cause of the documented increase (note not the cause of the "increase," not
> > that humans do not start fires) in Western USA fires in recent decades:
> > 
> > http://www.sciencemag.org/cgi/content/full/313/5789/940
> > 
> > We compiled a comprehensive database of large wildfires in western United
> > States forests since 1970 and compared it with hydroclimatic and
> > land-surface data. Here, we show that large wildfire activity increased
> > suddenly and markedly in the mid-1980s, with higher large-wildfire
> > frequency, longer wildfire durations, and longer wildfire seasons. The greatest
> > increases occurred in mid-elevation, Northern Rockies forests, where
> > land-use histories have relatively little effect on fire risks and are
> > strongly associated with increased spring and summer temperatures and an
> > earlier spring snowmelt.
> > --------------------
> > 
> > I will excerpt a few more paragraphs from this article:
> > 
> > 
> > *Science* 18 August 2006:
> > Vol. 313. no. 5789, pp. 940 - 943
> > DOI: 10.1126/science.1128834
> >  Prev <http://www.sciencemag.org/cgi/content/short/313/5789/936> | Table of
> > Contents <http://www.sciencemag.org/content/vol313/issue5789/index.dtl> |
> > Next <http://www.sciencemag.org/cgi/content/short/313/5789/944>
> > Research Articles Warming and Earlier Spring Increase Western U.S. Forest
> > Wildfire Activity *A. L.
> > Westerling,1,2*<http://www.sciencemag.org/cgi/content/full/313/5789/940#COR1>
> > H.
> > G. Hidalgo,1 D. R. Cayan,1,3 T. W. Swetnam4 *
> > 
> > http://www.sciencemag.org/cgi/content/full/313/5789/940
> > 
> > We compiled a comprehensive database of large wildfires in western United
> > States forests since 1970 and compared it with hydroclimatic and
> > land-surface data. Here, we show that large wildfire activity increased
> > suddenly and markedly in the mid-1980s, with higher large-wildfire
> > frequency, longer wildfire durations, and longer wildfire seasons. The greatest
> > increases occurred in mid-elevation, Northern Rockies forests, where
> > land-use histories have relatively little effect on fire risks and are
> > strongly associated with increased spring and summer temperatures and an
> > earlier spring snowmelt.
> > ------
> > 
> > Snow carries over a substantial portion of the winter precipitation that
> > falls in western mountains, releasing it more gradually in late spring and
> > early summer, providing an important contribution to spring and summer soil
> > moisture (*35*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF35>).
> > An earlier snowmelt can lead to an earlier, longer dry season, providing
> > greater opportunities for large fires due both to the longer period in which
> > ignitions could potentially occur and to the greater drying of soils and
> > vegetation. Consequently, it is not surprising that the incidence of
> > wildfires is strongly associated with snowmelt timing.
> > 
> > Changes in spring and summer temperatures associated with an early spring
> > snowmelt come in the context of a marked trend over the period of analysis.
> > Regionally averaged spring and summer temperatures for 1987 to 2003 were
> > 0.87°C higher than those for 1970 to 1986. Spring and summer temperatures for
> > 1987 to 2003 were the warmest since the start of the record in 1895, with 6
> > years in the 90th percentile—the most for any 17-year period since the start
> > of the record in 1895 through 2003—whereas only 1 year in the preceding 17
> > years ranked in the 90th percentile. Likewise, 73% of early years since 1970
> > occurred in 1987 to 2003 (Fig.
> > 1<http://www.sciencemag.org/cgi/content/full/313/5789/940#FIG1>
> > ).
> > 
> > --------
> > 
> > If the average length and intensity of summer drought increases in the
> > Northern Rockies and mountains elsewhere in the western United States, an
> > increased frequency of large wildfires will lead to changes in forest
> > composition and reduced tree densities, thus affecting carbon pools. Current
> > estimates indicate that western U.S. forests are responsible for 20 to 40%
> > of total U.S. carbon sequestration
> > (*38*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF38>,
> > *39* <http://www.sciencemag.org/cgi/content/full/313/5789/940#REF39>). If
> > wildfire trends continue, at least initially, this biomass burning will
> > result in carbon release, suggesting that the forests of the western United
> > States may become a source of increased atmospheric carbon dioxide rather
> > than a sink, even under a relatively modest temperature-increase scenario (*
> > 38* <http://www.sciencemag.org/cgi/content/full/313/5789/940#REF38>,
> > *39*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF39>).
> > Moreover, a recent study has shown that warmer, longer growing seasons lead
> > to reduced CO2 uptake in high-elevation forests, particularly during
> > droughts (*40*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF40>).
> > Hence, the projected regional warming and consequent increase in wildfire
> > activity in the western United States is likely to magnify the threats to
> > human communities and ecosystems, and substantially increase the management
> > challenges in restoring forests and reducing greenhouse gas emissions.
> > 
> > ------
> > 
> > Vision2020 Post: Ted Moffett
> > 
> > 
> 
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