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Bark Beetles, Drought and Climate

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Bark Beetles, Drought and Climate Becky Estes Beverly M. Bulaon Central Sierra Province Ecologist South Sierra Shared Service Area USDA Forest Service Forest Health Protection Beetles: mountain, western, Jeffrey pine beetles; engravers; red turpentine beetle • Aggressive beetles in terms of host selection, populations, behavior • Typically prefer larger-diameter trees or stressed hosts • Moisture driven • Group/single mortality pattern BEETLES • Mortality associated with stand C. Fettig, USDA Forest Service composition, stem density, host condition Jeffrey Pine Jeffrey pine beetles; Engravers; Pandora Moth; needleminers Ponderosa Pine Western, Mountain pine beetles; Engravers Mountain pine beetles; Engravers 5-needled Pine Lodgepole Pine Mountain pine beetles; Engravers Lodgepole needle miner BEETLES Pinyon Pine Pinyon engraver, Ips species; pinyon sawfly; needle scale All Pines Pine Needle Scale; Black Pine Leaf Scale; Red Turpentine Beetle Giant Sequoia Woodborers Incense Cedar Phloeosinus sp. Xylococculus macrocarpae Mountain Hemlock Scolytus sp. Torrey Pine Mealybug: Puto sp. Oaks Pseudopityophthorus pubipennis; Western Tussock Moth; Gall Wasps; Gold Spotted Oak Borer Douglas-fir Flatheaded Fir borer BEETLES Scolytus sp.; Flatheaded & True Firs Roundheaded fir borers; Douglas- fir Tussock Moth Resource Partitioning in Pines Pine Engravers Western Pine Beetle; Mountain Pine Beetle; Jeffrey Pine Beetle < 6 inches/horizontal: • Pine engravers BEETLES Red Turpentine Dead tree: • Woodborers • Ambrosia Beetles • Pouch Fungus • Ants BEETLES • Termites • Conks Resource Partitioning in Firs < 4 inches: Scolytus praeceps Scolytus subscaber Fir Engraver Woodborers Ambrosia BEETLES Beetles Root Disease!!! How Bark Beetles Cause Tree Mortality 272. • Invade the bark of living trees – • Colonize, mate, and reproduce in 56:255 . phloem/cambium Entomol . Rev. Rev. BEETLES Six Six Wingfieldand 2011. Ann How Bark Beetles Cause Tree Mortality • Introduce fungi • Clogs tree conduction • Tree death occurs by girdling of the phloem (i.e., layers of cells just inside the bark that transport photosynthate) by both colonizing adults and developing larvae BEETLES • Able to kill trees C. Fettig, USDA Forest Service • Often stressed trees in endemic levels • “Healthy” trees at epidemic levels BEETLES BEETLES Temperatures are climbing in California 16.7 16.1 15.6 California: mean 15 annual temps, 1920-2005 14.4 13.9 Moser et al. 2009 13.3 C L I M A T E T A I M L C Tahoe City: number of days below freezing, 1910-2009 TERC 2009 70 y = 0.0174x + 22.087 Nighttime R2 = 0.076, NS 60 Mean max temperatures 50 Mean drive the pattern 40 y = 0.0298x - 15.196 R2 = 0.363, P = 0.056 Degrees Fahrenheit Mean min 30 Tahoe City: 1899 m y = 0.0422x - 52.554 R2 = 0.574, P < 0.0001 elevation 20 10 1.7° F increase in day-time temps 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year 4.2° F increase in night-time temps! 2 Grants Grove 60 Mean Max: y = 0.008x+40.982; R = 0.0137, NS (Sequoia-Kings 2 Canyon NP): 2006 m 50 Mean: y = 0.0395x-31.6, R = 0.3515, P< 0.0001 elevation Mean Min: y = 0.0722x-106.73, R2 = 0.5827, P <0.0001 40 Degrees Farenheit C L I M A T E T A I M L C 0.8° F increase in day- 30 Mean Min Mean time temps Mean Max 20 7.2° F increase in night- 1940 1950 19 60 1970 1980 1990 2000 2010 Year time temps! Future climate: models project more of the same – mean annual +2.5° temperature to 4 ° C C L I M A T E T A I M L C early 20th century vs. early 21st century Graphic courtesy of S. Dobrowski, Univ of MT Moser et al. 2009 Precipitation was ~steady or rising in N. California, until the recent drought! WRCC 2009 SoCal: Precipitation is ~steady over long-term, but dropping over C L I M A T E T A I M L C last 25-35 years WRCC 2010 Precipitation early th Future climate: snowpack 20 century vs. early 2010-2100 21st century NorCal: somewhat warmer, wetter C L I M A T E T A I M L C SoCal: much warmer, a little drier Graphic courtesy of S. Dobrowski, Univ of MT CalFire-FRAP, draft 2010 Current Feb 17, 2015 Feb 16, 2016 Feb 18, 2014 Nov 15, 2016 Feb 19, 2013 Feb 21, 2012 Feb 15, 2011 Feb 21, 2010 is “worst 1200 in years” Current California drought Feb 21, 2006 Feb 17, 2009 Feb 21, 2008 Feb 20, 2007 http://droughtmonitor.unl.edu/ Bark beetle mortality driven by drought cycles BEETLES U.S. Forest Service Region 5 State and Private Forestry Mortality is typically higher in lower elevation forests, which are more moisture limited, and where densities are enhanced by fire suppression High Low BEETLES BEETLES Data from Zack Heath, USFS-FHP Insect/Disease Summary 1. Bark beetle mortality driven by drought cycles 2. Mortality is typically higher in lower elevation forests, which are more moisture limited, and where densities are enhanced by fire suppression 3. Stress due to drought and exacerbated by BEETLES BEETLES high forest densities = alarming increase in forest mortality RISK RISK Effectiveness of forest management treatments at reducing drought and bark- beetle caused tree mortality in California. MANAGEMENT MANAGEMENT QUESTIONS??.
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