Global Warming Science - www.appinsys.com/GlobalWarming
Mountain Pine Bark Beetle Devastating Western Pine Forests
[last update: 2011/03/26]
“Across western North America, from Mexico to Alaska, forest die-off is occurring on an extraordinary scale, unprecedented in at least the last century-and-a-half — and perhaps much longer. All told, the Rocky Mountains in Canada and the United States have seen nearly 70,000 square miles of forest — an area the size of Washington state — die since 2000. … These large-scale forest deaths from beetle infestations are likely a symptom of a bigger problem, according to scientists: warming temperatures and increased stress, due to a changing climate.”
Mountain Pine Beetle
The Mountain Pine Beetle (MPB) is the most important pine killing insect in western North America.
Mountain Pine Beetle – USDA Forest Service [http://www.barkbeetles.org/mountain/fidl2.htm]
The following points are from the above referenced “Forest Insect and Disease Leaflet 2 - 1989” (written prior to the 2000s epidemic).
Mountain Pine Beetle – Colorado State University [http://www.ext.colostate.edu/pubs/insect/05528.html]
The following points are from the above referenced “Fact Sheet”.
USDA Research Paper RM-235 “Ponderosa Pine Mortality Resulting from a Mountain Pine Beetle Outbreak” 1982 [http://www.fs.fed.us/rm/pubs_rm/rm_rp235.pdf]:
Mountain Pine Beetle Epidemics – Congressional Research Service Report for Congress 2009 [http://www.scribd.com/doc/12965052/CRS-Report-Mountain-Pine-Beetles]
September 2009: “After more than a decade of devastation, B.C.'s Forests Minister says the plague of the Pine Beetle may finally be over. … the pine beetle is really on the decline. Unfortunately, that's as a result of it running out of food at this point … The pine beetle infestation has ravaged nearly 25 per cent of B.C.'s pine trees” [http://www.cbc.ca/canada/british-columbia/story/2009/09/22/bc-pine-beetle-bell.html]
That’s the same percentage killed in Northern Colorado between 1965 – 1978 (when global cooling was the scare).
Council of Forest Industries
Canadian Forestry Service – Mountain Pine Beetle Synthesis Report, 2006
The various reports refer to “warming trends” making the pines more susceptible, but they do not provide local region data – they simply refer to global trends.
The following figures shown monthly average temperature anomalies for the two 5x5 degree grids covering south and central BC for Oct through March – the critical months for pine beetle mortality. (Plots of HadCRU CRUTEM3 data plotted at http://www.appinsys.com/GlobalWarming/climate.aspx) Plots for 1910 through 2009.
The above temperature anomaly plots correspond to the 5x5 degree grids shown on the map below right.
The figure below right shows the summer precipitation at Kamloops – no drying trend.
The following figure shows the MPB tree kill extent by 2006.
The following figure shows Colorado winter temperatures (left) and summer temperatures (right) from the NOAA NCDC data [http://www.ncdc.noaa.gov/oa/climate/research/cag3/co.html]
A Colorado State University Study found that the amount of uniform mature stands of pine has increased over the last century [http://warnercnr.colostate.edu/images/docs/cfri/CFRIPonderosa.pdf]
The following figure shows the Sugarloaf area near Boulder
Another 2006 study states: “There is no evidence to support the idea that current levels of bark beetle or defoliator activity are unnaturally high. Similar outbreaks have occurred in the past”
A historical perspective of drought in Colorado:
There is a lack of long-term rural stations in the area of Colorado affected by MPB (area shown on map below) in the NOAA US climate network. (Map from http://csfs.colostate.edu/pages/mountain-pine-beetle.html)
The following figures show average January and minimum January temperatures for Steamboat Springs (top - location indicated by the red oval) and Cheesman (bottom - location indicated by blue oval). The temperatures are within natural variance.
The following figure shows the area of Montana affected by the MPB (area shaded in red – forested area shaded in green).
The following figure shows the acreage by age class of lodgepole pine (from the same source as above). Most of the trees are in the most susceptible age class of 80 years or older. The above source states: “In some areas of Montana, wildfire suppression and other factors have led to overstocked forests, in which many trees are growing in close proximity, competing for water, sunlight and nutrients.”
It also states: “in Montana, an estimated 506,000 acres of ponderosa pine are in the “fully stocked” and Overstocked” categories and thus at high risk. … Given the factors of age and stocking conditions for lodgepole pine and ponderosa pine, more than 2.8 million acres of Montana’s forested lands are at high risk for mountain pine beetle infestation. The last major outbreak in Montana occurred in the 1970s and early 1980s, when some four million acres were affected. … Montana’s current outbreak has not yet reached the levels seen in the early 1980s.”
The graph below shows acreage affected by mountain pine beetle over the past 33 years (through 2008) in the USDA Forest Service’s Northern Region, which includes the Idaho Panhandle, all of Montana, and North Dakota (from the same source as above).
January 21, 2010: the Billings Gazette reports: “The acreage of pine forest in Montana infested with the mountain pine beetle more than doubled in 2009, but a forester says the epidemic is losing steam in some areas. Pine beetles infested 1.2 million acres of forest in 2008 and 2.7 million acres in 2009, based on aerial surveys. Most of the outbreak has occurred in forests near Butte, Anaconda and Helena.”
The following figure shows the average minimum January temperature for Anaconda and Butte from the NOAA GHCN database (plotted at: http://www.appinsys.com/GlobalWarming/climate.aspx) No long-term warming trend is evident in the January minimum temperatures.
See also Western Montana regional study: http://www.appinsys.com/GlobalWarming/RS_Montana_usa.htm
Historical Newspaper Articles
Spokane Daily Chronicle – June 4, 1948
Berkeley Daily Gazette – June 6, 1930