References

Recent research papers and reports on these bark beetle topics:

Overview/Multiple Topics

Water Quantity and Quality Impacts

Climate, Climate Change and Bark Beetles

Fire Behavior and Fire Risk Post-Infestation

Falling Tree Hazards

Ecology and Biology of Bark Beetles

Socioeconomic and Policy Research


Note: If the title of the reference is hyperlinked, the link will open a PDF of the reference, or a webpage to access the reference.

Overview/Multiple Topics

Bark Beetle Outbreaks in Western North America: Causes and Consequences
Bentz, B., ed., 2009: University of Utah Press. Note: Full report is not available online and must be ordered through the link above.

Recent Forest Insect Outbreaks and Fire Risk in Colorado Forests: A Synthesis of Relevant Research
Romme, B., et al., 2006: Colorado Forest Restoration Institute report.

Clarification Statement by Romme et al. 2006 authors regarding the linkage between beetle outbreaks and climate

The status of our scientific understanding of lodgepole pine and mountain pine beetles – a focus on forest ecology and fire behavior
Kaufmann, M.R., et al. 2008.The Nature Conservancy, Arlington, VA. GFI technical report 2008-2.

The Western Bark Beetle Research Group: A unique collaboration with Forest Health Protection
Hayes, J. L., Lundquist, J. E., comps., 2009: Proceedings of a symposium at the 2007 Society of American Foresters conference. Gen. Tech. Rep. PNW-GTR-784. USDA Forest Service.

Insects and Roadless Forests: A Scientific Review of Causes, Consequences, and Management Alternatives
Black, S.H., Kulakowski, D., Noon, B.R., DellaSalla, D., 2010: National Center for Conservation Science and Policy, Ashland, OR.

 

Water Quantity and Quality Impacts

SYNTHESIS REPORTS, CHAPTERS, AND ARTICLES:

Impacts of the mountain pine beetle infestation on the hydrologic cycle and water quality: A symposium report and summary of the latest science
Lukas, J. and Gordon, E., 2010: Intermountain West Climate Summary 6:4 (May 2010), Western Water Assessment.

Biogeochemistry of beetle-killed forests: Explaining a weak nitrate response
Rhoades, C. C., et al., 2013: Proceedings of the National Academy of Sciences. doi: 10.1073/pnas.1221029110

A conceptual model of water yield impacts from beetle-induced tree death in snow-dominated lodgepole pine forests
Pugh, E. and E. Gordon, 2012: Hydrological Processes. doi: 10.1002/hyp.9312.

Review and Synthesis of Potential Hydrologic Impacts of Mountain Pine Beetle and Related Harvesting Activities in British Columbia
Hélie, J.F., Peters, D.L., Tattrie, K.R., and Gibson, J.J. Canadian Forest Service, Mountain Pine Beetle Initiative Working Paper 2005-23.

Ecohydrological consequences of drought- and infestation- triggered tree die-off: insights and hypotheses.
Adams, H. D., et al., 2011: Ecohydrology, doi: 10.1002/eco.233

Hydrologic Impacts of a Changing Forest Landscape
Committee on Hydrologic Impacts of Forest Management, National Research Council, 2008.

Forests and Water: A State-of-the-Art Review for Colorado
MacDonald, Lee H. and Stednick, John D., 2003: Colorado Water Resources Research Institute Completion Report No. 196.

RESEARCH PAPERS:

Colorado and Western U.S.

(Also see: Abstracts and Presentations from the WWA MPB Science Symposium: Impacts on the Hydrologic Cycle and Water Quality on April 8, 2010, Boulder, CO, and Abstracts and Presentations from the 2nd WWA MPB Science Symposium: Impacts on the Hydrologic Cycle and Water Quality, on April 25, 2011)

Bethlahmy N. 1974. More streamflow after a bark beetle epidemic. Journal of Hydrology 23: 185–189. (ABSTRACT)

Bethlahmy N., 1975: A Colorado episode: beetle epidemic, ghost forests, more stream flow. Northwest Science 49(2): 95–105. (ABSTRACT)

Love LD. 1955. The effect on stream flow of the killing of spruce and pine by the Engelmann spruce beetle. Transactions of the American Geophysical Union, 36(1): 113–118. (ABSTRACT)

Morehouse, K., Johns, T., Kaye, J. and Kaye., M., 2008: Carbon and nitrogen cycling immediately following bark beetle outbreaks in southwestern ponderosa pine forests. Forest Ecology and Management 255: 2698-2708. (ABSTRACT)

Potts, D.F., 1984: Hydrologic Impacts of a Large-Scale Mountain Pine Beetle (Dendroctonous ponderosae Hopkins) Epidemic. Water Resources Bulletin 20(3): 373-377. (ABSTRACT)

Pugh, E. and E. Gordon, 2012: A conceptual model of water yield impacts from beetle-induced tree death in snow-dominated lodgepole pine forests. Hydrological Processes. doi: 10.1002/hyp.9312.

Pugh, E., and Small, E. 2011. The impact of pine beetle infestation on snow accumulation and melt in the headwaters of the Colorado River. Ecohydrology, DOI: 10:1002/eco.329. (ABSTRACT)

Schmid, J.M., Mata, S.A., Martinez, M.H., and Troendle, C.A., 1991: Net Precipitation Within Small Group Infestations of the Mountain Pine Beetle. Research Note RM-508, USDA Forest Service Rocky Mountain Forest and Range Experiment Station. (ABSTRACT)

Stednick, J.D., and Jensen, R., 2007: Effects of Pine Beetle Infestations on Water Yield and Water Quality at the Watershed Scale in Northern Colorado. Report as of FY2007 for 2007CO153B, Colorado Water Resources Research Institute.

Troendle, C. A., & Nankervis, J. M. ,2000: Estimating Additional Water Yield from Changes in Management of National Forests in the North Platte Basin. Report to the U.S. Bureau of Reclamation.

Canada

Bewley, D., Y. Alila, and A. Varhola. 2010. Variability of snow water equivalent and snow energetics across a large catchment subject to Mountain Pine Beetle infestation and rapid salvage logging. Journal of Hydrology 388: 464–479.

Boon S., 2007: Snow accumulation and ablation in a beetle-killed pine stand, northern Interior British Columbia. BC Journal of Ecosystems and Management 8(3): 1-13.

Boon, S., 2009: Snow ablation energy balance in a dead forest stand. Hydrological Processes 23: 2600-2610. (ABSTRACT)

Cheng, J.D. 1989. Streamflow changes after clear-cut logging of a pine beetle-infested watershed in southern British Columbia, Canada. Water Resources Research, 25(3): 449-456. (ABSTRACT)

Grainger, B., and Bates, A., 2010: A Semi-Quantitative Risk Analysis for a Mountain Pine Beetle Infested Watershed in the Southern Interior of British Columbia. Streamline Watershed Management Bulletin 13(2).

Lewis, D., and Huggard, D., 2010: A Model to Quantify Effects of Mountain Pine Beetle on Equivalent Clearcut Area. Streamline Watershed Management Bulletin 13(2).

Maloney, D., 2005: Mid-term impact of mountain pine beetle on watershed hydrology. Association of BC Forest Professionals Forum 12(3): 23. 

Teti, P., 2010: The Canopy Structure and Snow Hydrology of Managed Lodgepole Pine Stands Compared with Beetle-Killed Stands. Streamline Watershed Management Bulletin 13(2).

Uunila, L., Guy, B., and Pike, R., 2006: Hydrologic Effects of Mountain Pine Beetle in the Interior Pine Forests of British Columbia: Key Questions and Current Knowledge. Streamline Watershed Management Bulletin 9(2): 1-6. 

Winkler, R., and Boon, S., 2010: The Effects of Mountain Pine Beetle Attack on Snow Accumulation and Ablation: A Synthesis of Ongoing Research in British Columbia. Streamline Watershed Management Bulletin 13(2).

Germany

Huber, C. 2005. Long lasting nitrate leading after bark beetle attack in the Highlands of the Bavarian Forest National Park. Journal of Environmental Quality, 34: 1772-1779. (ABSTRACT)

Huber, C., Baumgarten, Gottlein, A. and V. Rotter. 2004. Nitrogen turnover and nitrate leaching after bark beetle attack in mountainous spruce stands of the Bavarian National forest Park. Water, Air, Soil Pollution Focus, 4(2-3): 391-414. (ABSTRACT)

 

Climate, Climate Change and Bark Beetles

SYNTHESIS REPORTS AND PAPERS:

Amman, G.D.; Cole, W.E., 1983. Mountain pine beetle dynamics in lodgepole pine forests. Part II: population dynamics. Gen. Tech. Rep. INT-145 Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. UT. 59 p.

Bark Beetle Outbreaks in Western North America: Causes and Consequences
Bentz, B., ed., 2009: University of Utah Press. Note: Full report is not available online and must be ordered through the link above.

Bentz B.J., Régnière, J., Fettig, C.J. et al., 2010. Climate change and bark beetles of the western United States and Canada: direct and indirect effects. BioScience 60, 602–13.

Raffa, K. F.; Aukema, B. H.; Bentz, B. J.; Carroll, A. L.; Hicke, J. A.; Turner, M. G.; Romme, W. H. 2008. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: Dynamics of biome-wide bark beetle eruptions. BioScience. 58(6): 501-518.

Régnière J., Bentz, B.J. 2009. Mountain pine beetle and climate change. In: McManus, K. A; Gottschalk, K. W., eds. Proceedings. 19th U.S. Department of Agriculture interagency research forum on invasive species 2008; 2008 January 8-11; Annapolis, MD. Gen. Tech. Rep. NRS-P-36. USDA Forest Service, Northern Research Station.

RESEARCH PAPERS:

Bentz B.J.,Logan J.A.,Amman G.D. 1991. Temperature-dependent development of the mountain pine beetle (Coleoptera, Scolytidae) and simulation of its phenology. Canadian Entomologist 123: 1083–1094.

Bentz, B.J.; Mullins, D.E. 1999. Ecology of mountain pine beetle cold hardening in the Intermountain West. Environmental Entomology. 28(4): 577-587.

Brunelle, A.; Rehfeldt, G. E.; Bentz, B.; Munson, A. S. 2008. Holocene records of Dendroctonus bark beetles in high elevation pine forests of Idaho and Montana, USA. Forest Ecology and Management. 255: 836-846.

Carroll AL, Taylor SW, Régnière J, Safranyik L. 2004. Effects of climate change on range expansion by the mountain pine beetle in British Columbia.
In: Shore TL, Brooks JE, Stone JE, eds.Mountain Pine Beetle Symposium: Challenges and Solutions. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre. Information Report BC-X-399.

Hicke, J. A., J. A. Logan, J. Powell, and D. S. Ojima. 2006. Changing temperatures influence suitability for modeled mountain pine beetle (Dendroctonus ponderosae) outbreaks in the western United States. Journal of Geophysical Research-Biogeosciences 111, G02019. (ABSTRACT)

Kurz W.A., Dymond C.C., Stenson G., Rampley G.J., Carroll A.L., Ebata T., Safranyik L. 2008. Mountain pine beetle and forest carbon feedback to climate change. Nature 452: 987–990.

Logan J.A., Powell J.A. 2001. Ghost forests, global warming, and the mountain pine beetle (Coleoptera: Scolytidae). American Entomologist 47: 160–173.

Logan J.A.,Régnière J., Powell J.A. 2003. Assessing the impacts of global warming on forest pest dynamics. Frontiers in Ecology and the Environment 1: 130–137.

Powell, J. A.; Bentz, B. J. 2009. Connecting phenological predictions with population growth rates for mountain pine beetle, an outbreak insect. Landscape Ecology. 24: 657-672..

Régnière J., Bentz, B.J.. 2007. Modeling cold tolerance in the mountain pine beetle, Dendroctonus ponderosae. Insect Physiology 53: 559–572.

Thomson A.J., Shrimpton D.M. 1984. Weather associated with the start of mountain pine-beetle outbreaks. Canadian Journal of Forest Research 14: 255–258.

Williams, D. W.; Liebhold, A. M. 2002. Climate change and the outbreak ranges of two North American bark beetles. Agricultural and Forest Entomology 4:87-99.

 

Fire Behavior and Fire Risk Post-Infestation

SYNTHESIS REPORTS AND CHAPTERS:

Bark Beetle Outbreaks in Western North America: Causes and Consequences
Bentz, B., ed., 2009: University of Utah Press. Note: Full report is not available online but can be ordered through the link above.

Recent Forest Insect Outbreaks and Fire Risk in Colorado Forests: A Synthesis of Relevant Research
Romme, B., Clement, J., Hicke, J., Kulakowski, D., MacDonald, L., Schoennagel, T., and Veblen, T., 2006: Colorado Forest Restoration Institute report.

The status of our scientific understanding of lodgepole pine and mountain pine beetles – a focus on forest ecology and fire behavior
Kaufmann, M.R., et al. 2008.The Nature Conservancy, Arlington, VA. GFI technical report 2008-2.

Fire and bark beetle interactions
Gibson, K., Negron, J. F. 2009. In: Hayes, J. L.; Lundquist, J. E., comps. The Western Bark Beetle Research Group: Proceedings of a symposium at the 2007 SAF conference. Gen. Tech. Rep. PNW-GTR-784. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: pp 51-70.

RESEARCH PAPERS:

Lynch J.H.,Renkin R.A.,Crabtree R.L.,Moorcroft P.R.. 2006.The influence of previous mountain pine beetle (Dendroctonus ponderosae) activity on the 1988 Yellowstone fires. Ecosystems 9: 1318–1327.

 

Falling Tree Hazards

RESEARCH PAPERS:

Keen, F.P., 1955: The Rate of Natural Falling of Beetle-Killed Ponderosa Snags. Journal of Forestry 53: 720-725. (ABSTRACT)

Mitchell, R.G. and Preisler, H.K., 1998: Fall Rate of Lodgepole Pine Killed by the Mountain Pine Beetle in Central Oregon. Western Journal of Applied Forestry 13: 23-26. (ABSTRACT)

Schmid, J.M., Mata, S.A., and McCambridge, W.F., 1985: Natural Falling of Beetle-Killed Ponderosa Pine. Research Note RM-454, Fort Collins, CO: USDA Forest Service Rocky Mountain Forest and Range Experiment Station. (ABSTRACT)

Schmid, J.M., Mata, S.A., and Schaupp, Jr., W.C., 2009: Mountain Pine Beetle-Killed Trees as Snags in Black Hills Ponderosa Pine Stands. (ABSTRACT)

 

Ecology and Biology of Bark Beetles

SYNTHESIS REPORTS AND PAPERS:

Bark Beetle Outbreaks in Western North America: Causes and Consequences
Bentz, B., ed., 2009: University of Utah Press. Note: Full report is not available online but can be ordered through the link above.

Recent Forest Insect Outbreaks and Fire Risk in Colorado Forests: A Synthesis of Relevant Research
Romme, B., Clement, J., Hicke, J., Kulakowski, D., MacDonald, L., Schoennagel, T., and Veblen, T., 2006: Colorado Forest Restoration Institute report.

The status of our scientific understanding of lodgepole pine and mountain pine beetles – a focus on forest ecology and fire behavior
Kaufmann, M.R., et al. 2008.The Nature Conservancy, Arlington, VA. GFI technical report 2008-2.

Fire and bark beetle interactions
Gibson, K., Negron, J. F. 2009. In: Hayes, J. L.; Lundquist, J. E., comps. The Western Bark Beetle Research Group: Proceedings of a symposium at the 2007 SAF conference. Gen. Tech. Rep. PNW-GTR-784. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: pp 51-70.

Raffa, K. F.; Aukema, B. H.; Bentz, B. J.; Carroll, A. L.; Hicke, J. A.; Turner, M. G.; Romme, W. H. 2008. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: Dynamics of biome-wide bark beetle eruptions. BioScience. 58(6): 501-518.

 

Socioeconomic and Policy Research

REPORTS:

Economic Values at Risk: Economic Indicators for Five Bark Beetle Infested Counties of Colorado
Retzlaff, M. 2008. Report to the USDA Forest Service, Bark Beetle IMT.

Mountain Pine Beetles and Invasive Plant Species: Findings from a Survey of Colorado Community Residents
Flint, C., Qin, H., and Daab, M. Report to USDA Forest Service Pacific Northwest Research Station.

RESEARCH PAPERS:

Flint, C.G., McFarlane, B., and Müller, M., 2008: Human Dimensions of Forest Disturbance by Insects: An International Synthesis. Environmental Management 43(6): 1174-1186. (ABSTRACT)

Parkins, J.R., 2008: The Metagovernance of Climate Change: Institutional Adaptation to the Mountain Pine Beetle Epidemic in British Columbia. Journal of Rural and Community Development 3(2): 7-26. (ABSTRACT)

 



 

ABSTRACTS

Water Quantity and Quality Impacts

Bethlahmy N., 1975: A Colorado episode: beetle epidemic, ghost forests, more stream flow. Northwest Science 49(2): 95–105.
ABSTRACT: When a small watershed is clearcut, it temporarily yields more water. The implication is thatwater yield and land use are closely related. This interdependence is illustrated for two large watershedsin Colorado where bark beetles destroyed the living timber trees. Substantially greaterwater yields are still evident 25 –years after the epidemic because significant elements of the-watersheds have nor yet reverted to their former status—dead trees still occupy the land, and have notyet been replaced by live trees. The variable hydrologic effects of the epidemic-in the studiedwatersheds reflect differences in their exposures.

 

Bethlahmy N. 1974. More streamflow after a bark beetle epidemic. Journal of Hydrology 23: 185–189.
ABSTRACT: A beetle epidemic near the Continental Divide in Colorado destroyed the timber in two large drainages but bypassed a third drainage. Long-term streamflow records were available for the three drainages for the periods before and after the onset of the epidemic. Analysis of these records reveals that a major increase in streamflow occurred after the epidemic.

 

Boon S., 2007: Snow accumulation and ablation in a beetle-killed pine stand, northern Interior British Columbia. BC Journal of Ecosystems and Management 8(3): 1-13.
ABSTRACT: This preliminary study examined the impact of mountain pine beetle (Dendroctonus ponderosae) infestation and subsequent canopy mortality on ground snow accumulation and ablation in lodgepolepine (Pinus contorta) stands. During the winter of 2005–2006, meteorological and snow conditions were  measured in three stands—dead, alive, and cleared—in Northern Interior British Columbia. Variations in measured snow conditions and meteorological data between stands were assessed. Data were usedin an energy-balance model to calculate snow ablation in each stand and estimate effect on meltwater production. Results showed that the dead stand no longer behaved like an alive stand, but had not yet approached cleared stand conditions. Ablation rates in the dead stand remained similar to those in the alive stand, although accumulation was closer to that in the cleared stand. The combination of a low ablation rate and increased ground snow accumulation in the dead stand resulted in a lengthened period of snowpack disappearance. In the cleared stand, however, high ablation rates were sufficient to remove thethicker snowpack earlier than in the dead stand. A multi-year study is under way at a new research site to further quantify the relationship between beetle-kill and its effect on snowpack.

 

Boon, S., 2009: Snow ablation energy balance in a dead forest stand. Hydrological Processes 23: 2600-2610.
ABSTRACT: Forest disturbance has a significant impact on hydrology dueto its effect on the forest canopy, which is important forprecipitation interception, transpiration, site micrometeorology, and snow accumulation and ablation. This study examines theimpact of mountain pine beetle infestation and subsequent forest death on snow ablation.Dead stands experience needle loss andcanopy reduction due mainly to the loss of small branches and stems, which has a subsequent impact on micrometeorologicalconditions. Ablation is driven largely by incoming short-wave radiation, which in dead stands is greater than in alive stands,but does not reach that available in clearcuts. Long-wave radiation emission in dead stands is lower than that in alive stands,reducing its contribution to snowpack warming and ablation. Turbulent flux contributions to snow ablation are limited inforest stands relative to clearcuts, although they are slightlygreater in dead than alive stands due to the more open foreststructure. Additional studies are required to refine the basic energy balance model and incorporate all processes affecting thesnow ablation energy balance.

 

Cheng, J.D. 1989. Streamflow changes after clear-cut logging of a pine beetle-infested watershed in southern British Columbia, Canada. Water Resources Research, 25(3): 449-456.
ABSTRACT: The paired watershed technique was used to assess the streamflow changes of Camp Creek in interior British Columbia after clear-cut logging occurred over 30% of its 33.9 km2 watershed. Existing hydrometric data for Camp Creek and those of an adjacent control, Greata Creek, were analyzed for both the 1971–1976 prelogging and 1978–1983 postlogging periods. Postlogging Camp Creek streamflow changes are characterized by increases in annual and monthly water yields and annual peak flows, as well as earlier annual peak flow and half flow volume occurrence dates. The direction and magnitude of these postlogging streamflow increases are clear and consistent. The results are in good agreement with the findings of most previous studies conducted on watersheds which generally have been smaller than 2.5 km2. This study provides strong evidence that changes in streamflow from a large forested watershed can be significant if a sizeable portion of its drainage area is clear-cut. Possible causes for the streamflow changes are discussed.

 

Huber, C. 2005. Long lasting nitrate leading after bark beetle attack in the Highlands of the Bavarian Forest National Park. Journal of Environmental Quality, 34: 1772-1779.
ABSTRACT: During the past decade bark beetle (Ips typographus) attackskilled nearly all of the Norway spruce [Picea abies (L.) Karst.]stands in the unmanaged zone in the highlands of the BavarianForest National Park. This study was conducted to predict ifand how long the catastrophic event might cause elevated nitrate concentration in seepage water, and if the presence of ground vegetation may reduce NO3 leaching.A chronosequence approach was used to investigate NO3leaching before and after the death of trees. Additionally,the impact of ground vegetation coverage on NO3 leachingwas determined. Flux weighted yearly NO3 concentrationswere significantly elevated in the first 5 yr after the diebackcompared with intact stands (27 µmolc L–1), withhighest concentrations in the fifth year after the dieback (579µmolc L–1). Lowest NO3 concentrations wereobserved 17 yr after the dieback (10 µmolc L–1).Suction cups in places without ground vegetation showed significantlyhigher NO3 concentrations of 163 to 727 µmolc L–1 (Year 2–5 after the dieback) than suction cups withoutvegetation. However, net uptake of N by ground vegetation observedduring the first 7 yr after the dieback was low on a plot scale.Compared with other severe disturbances in forests, NO3concentrations were elevated for a longer period. Due to highrates of precipitation, NO3 dilution occurred and concentrationsremained mostly below the European critical level for drinkingwater. Part of the observed heterogeneity in NO3 concentrationscould be attributed to different patterns of ground vegetationcoverage.

 

Huber, C., Baumgarten, Gottlein, A. and V. Rotter. 2004. Nitrogen turnover and nitrate leaching after bark beetle attack in mountainous spruce stands of the Bavarian National forest Park. Water, Air, Soil Pollution Focus, 4(2-3): 391-414.
ABSTRACT: More than 85% of the mountainous spruce forest of the Bavarian Forest National Park died after bark beetle attack during the last decade. The elemental budget of intact stands and of different stages after the dieback was investigated. N-fluxes in throughfall of intact stands were lower (12–16 kg ha-1 a-1) than in an earlier study in an intact mountainous spruce stand in the Bavarian Forest National Park and were reduced in the first years after the dieback (3–5 kg N ha-1 a-1). Nitrate-N fluxes by seepage water of intact stands at 40 cm depth, which is below the main rooting zone, were moderate (5–9 kg ha-1 a-1). After the dieback of the stands, NH4+ concentrations were increased in humus efflux as were NO3- concentrations in mineral soil. Due to the relatively high precipitation, dilution of the elemental concentrations in seepage was considerable. Therefore, NO3- concentrations were usually below the level of drinking water (806 mol NO3- L-1), with lowest concentrations after the snowmelt and highest in autumn. Nitrate concentrations were elevated from the first year until the 7th year after the dieback. Total NO3--N losses by seepage until the 7th year after the dieback equaled 543 kg N ha-1. Aluminium fluxes after the dieback were enhanced in the mineral soil from 55 to 503 mmolc m-2 a-1 (average of 8 yr), K+ fluxes from 8 to 37 mmolc m-2 a-1, and Mg2+ fluxes from 13 to 35 mmolc m-2 a-1. The consequences for the nutritional status of the ecosystem, the hydrosphere, and forest management are discussed in the paper.

 

Love LD. 1955. The effect on stream flow of the killing of spruce and pine by the Engelmann spruce beetle. Transactions of the American Geophysical Union, 36(1): 113–118.
ABSTRACT: An outbreak of the Engelmann spruce beetle on the White River Plateau of western Colorado killed the Engelmann spruce and lodgepole pine on a considerable portion of the 762-sq mi drainage basin of White River above the town of Meeker, Colorado. Statistical analyses were made to compare stream flow and water content of snow for White River with similar measurements made for the 206-sq mi drainage basin of Elk River above Clark, Colorado. The analyses show that the flow of White River increased after the beetle outbreak, and this increase is attributed to reduced interception of snow and to reduced transpiration by the beetle-killed trees. Total annual stream flow of White River was compared for three periods: (1) the 1937-1940 water years before the killing of the spruce and pine; (2) the 1941-1946 water years during which the beetle outbreak was most active; and (3) the 1947-1951 water years during which the killing of the mature and overmature spruce and pine had been completed. The average annual stream flow increased by 1.22 inches during 1941-1946 and by 2.28 inches during 1947-1951 as compared to the period 1937-1940 after adjustment was made for climatic fluctuations.

 

Morehouse, K., Johns, T., Kaye, J. and Kaye., M., 2008: Carbon and nitrogen cycling immediately following bark beetle outbreaks in southwestern ponderosa pine forests. Forest Ecology and Management 255: 2698-2708.
ABSTRACT: Bark beetle infestation is a well-known cause of historical low-level disturbance in southwestern ponderosa pine forests, but recent fire exclusion and increased tree densities have enabled large-scale bark beetle outbreaks with unknown consequences for ecosystem function. Uninfested and beetle-infested plots (n = 10 pairs of plots on two aspects) of ponderosa pine were compared over one growing season in the Sierra Ancha Experimental Forest, AZ to determine whether infestation was correlated with differences in carbon (C) and nitrogen (N) pools and fluxes in aboveground biomass and soils. Infested plots had at least 80% of the overstory ponderosa pine trees attacked by bark beetles within 2 years of our measurements. Both uninfested and infested plots stored 9 kg C m-2 in aboveground tree biomass, but infested plots held 60% of this aboveground tree biomass in dead trees, compared to 5% in uninfested plots. We hypothesized that decreased belowground C allocation following beetle-induced tree mortality would alter soil respiration rates, but this hypothesis was not supported; throughout the growing season, soil respiration in infested plots was similar to uninfested plots. In contrast, several results supported the hypothesis that premature needlefall from infested trees provided a pulse of low C:N needlefall that altered soil N cycling. The C:N mass ratio of pine needlefall in infested plots (45) was lower than uninfested plots (95) throughout the growing season. Mineral soils from infested plots had greater laboratory net nitrification rates and field resin bag ammonium accumulation than uninfested plots. As bark beetle outbreaks become increasingly prevalent in western landscapes, longer-term biogeochemical studies on interactions with other disturbances (e.g. fire, harvesting, etc.) will be required to predict changes in ecosystem structure and function.

 

Potts, D.F., 1984: Hydrologic Impacts of a Large-Scale Mountain Pine Beetle (Dendroctonous ponderosae Hopkins) Epidemic. Water Resources Bulletin 20(3): 373-377.
ABSTRACT: The Jack Creek watershed, a 133 km2 (51.5 mi2) drainage in southwestern Montana, was impacted by a mountain pine beetle (Dendroctonous ponderosae Hopkins) epidemic in 1975-1977 which killed an estimated 35 percent of its total timber. Analyses of USGS streamflow data for four years prior to and five years after mortality suggest a 15 percent post-epidemic increase in annual water yield, a two- to three-week advance in the annual hydrograph, a 10 percent increase in low flows and little increase of peak runoff.

 

Schmid, J.M., Mata, S.A., Martinez, M.H., and Troendle, C.A., 1991: Net Precipitation Within Small Group Infestations of the Mountain Pine Beetle. Research Note RM-508, USDA Forest Service Rocky Mountain Forest and Range Experiment Station.
ABSTRACT: Net precipitation (amount of precipitation reaching the ground) was monitored within four small group infestations of the mountain pine beetle from October 1986 to October 1990. Net precipitation within each infested group was not significantly different than its respective control. The lack of differences was attributed to needle retention on the infested trees during the first 2 years and to the presence of the bare, but dead, standing trees during the last 2 years. Sample size and aspect of the infested area may have influenced our ability to detect a change in net precipitation.

 

Schwarze, R. and Beudert, B., 2009. Analyses of flood generation and water budget in a forest catchment impacted by bark beetle outbreak. Hydrology and Water Resources Management-German 53(4): 236-249. [Note: article text is in German.]
ABSTRACT: To study the consequences of an extended dieback of mature stands of Norway spruce (Picea abies Karst.) under the impact of a bark-beetle outbreak for the water cycle and flood formation, a comprehensive set of methods was applied to hydrological and hydrochemical data of the Grosse Ohe catchment (19.1 km2) in the Bavarian Forest National Park. Statistical analysis of daily runoff revealed a significant increase in the total runoff due to decreases in evapotranspiration in the Grosse Ohe catchment and the Markungsgraben and Forellenbach sub-catchments, when dead spruce stands accounted there for more than 20% of the area. Runoff-component analysis showed that initially this increase is due to higher contributions of fast direct flow. In a later phase, direct flow decreased, while the fast groundwater component increased.The latter was caused by slowly decaying roots, which promote fast flow of water into the regolith. The analysis of a flood event in September 2004 showed 100% increase in peak discharge and 250% increase in flood runoff in the Markungsgraben catchment (88% dead spruce stands) compared with the Forellenbach catchment (42% dead spruce stands). The separation of the flood hydrograph using 18O revealed that event water and pre-event water amounted to 45% and 55% of the total discharge and to 61% and 39% of the flood discharge, resp. The variations of the groundwater table and the matric potential in different soil depths allowed to conclude that groundwater and deep-soil water did not contribute to the flood discharge, and that pre-event water was subsurface lateral flow which was mobilized by event water. The characteristic variations in runoff water quality during high flood were a decrease in SiO2 concentration and a fivefold to tenfold increase in DOC, K+, Al+ and Fe2+ concentrations, which were attributable to the soil organic layer and the uppermost mineral soil layer only. A mixing analysis with a synthetic fast component of organic-layer leachate (2/3) and throughfall (1/3) gave additional evidence that event water adopted the chemical fingerprint of the organic layers and the contiguous mineral soil during its passage to the stream channel.

 

 Climate and Climate Change

Hicke, J. A., J. A. Logan, J. Powell, and D. S. Ojima. 2006. Changing temperatures influence suitability for modeled mountain pine beetle (Dendroctonus ponderosae) outbreaks in the western United States. Journal of Geophysical Research-Biogeosciences 111, G02019.

ABSTRACT: Insect outbreaks are significant disturbances in forests of the western United States, with infestation comparable in area to fire. Outbreaks of mountain pine beetle (Dendroctonus ponderosae Hopkins) require life cycles of one year with synchronous emergence of adults from host trees at an appropriate time of year (termed ``adaptive seasonality'') to overwhelm tree defenses. The annual course of temperature plays a major role in governing life stage development and imposing synchrony on mountain pine beetle populations. Here we apply a process-based model of adaptive seasonality across the western United States using gridded daily temperatures from the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP) over the period 1895-2100. Historical locations of modeled adaptive seasonality overlay much of the distribution of lodgepole pine (Pinus contorta Douglas), a favored host, indicating that suitable temperatures for outbreak occurred in areas of host availability. A range of suitable temperatures, both in the mean and over an annual cycle, resulted in adaptive seasonality. Adaptive seasonality typically occurred when mean annual temperatures were 3°-6°C, but also included locations where mean temperatures were as low as 1°C or as high as 11°C, primarily as a result of variability in winter temperatures. For most locations, years of adaptive seasonality were uncommon during 1895-1993. We analyzed historical temperatures and adaptive seasonality in more detail in three northern forest ecoprovinces. In the Northern and Middle Rockies, areas of adaptive seasonality decreased at lower elevations and increased at higher elevations during warmer periods, resulting in a movement upward in elevation of adaptive seasonality. In contrast, the Cascade Mountains exhibited overall declines in adaptive seasonality with higher temperatures regardless of elevation. Projections of future warming (5°C in the western United States) resulted in substantial reductions in the overall area of adaptive seasonality. At the highest elevations, predicted warmer conditions will result in increases in the area of adaptive seasonality. Our findings suggest that future climate change may alter forest ecosystems indirectly through alteration of these important disturbances.

 

Tree Falls after Beetle Infestations

Keen, F.P., 1955: The Rate of Natural Falling of Beetle-Killed Ponderosa Snags. Journal of Forestry 53: 720-725.
Summary: The rate of natural fall of beetle-killed ponderosa pines in the interior ponderosa pine type of southeastern Oregon and northeastern California is primarily dependent upon time elapsed since death, but this rate is modified by tree size, soil conditions, and several unpredictable variables. Rate of fall in this study was slow for the first 5 years, with 85 percent of snags still standing at the end of that time. Then, as the effects of wood rots and wood borers accumulated, snags fell at an increasingly rapid rate between the fifth and fifteenth years. Small trees with much sapwood fell faster than the average. After the fifteenth year, the rate of fall decreased, and the larger, more resistant trees stood for a long time. After 25 years, 10 percent of the snags were still standing, including 25 percent or more of those in the 40-inch and larger diameter classes. It seems likely that some of the larger snags might stand for 50 years, if not felled by man.

 

Mitchell, R.G. and Preisler, H.K., 1998: Fall Rate of Lodgepole Pine Killed by the Mountain Pine Beetle in Central Oregon. Western Journal of Applied Forestry 13: 23-26.
ABSTRACT: The fall rate of nearly 600 lodgepole pines (Pinus contorta) killed by the mountain pine beetle (Dendroctonus ponderosae) in central Oregon was investigated in thinned and unthinned stands. Estimates were obtained by fitting a complementary log-log model to the conditional probabilities of trees falling within a given year. Snags began falling $ yr after death in thinned stands and 5 yr in unthinned stands. Small trees fell slightly faster than large trees in thinned stands, but tree size was not a factor in the fall rate in unthinned stands. In thinned stands, 50% were down in 8 yr and 90% were down in 12 yr. In unthinned stands, 50% were down in 9 yr and 90% were down in 14 yr. No particular calendar year had tree fall that was significantly greater than average. All beetle-killed trees broke off at the ground when they fell. The rate that trees fall in different environments may be related to the speed of bole decay at the ground level.

 

Schmid, J.M., Mata, S.A., and McCambridge, W.F., 1985: Natural Falling of Beetle-Killed Ponderosa Pine. Research Note RM-454, Fort Collins, CO: USDA Forest Service Rocky Mountain Forest and Range Experiment Station.
Abstract: Beetle-killed trees in the Front Range of Colorado were observed for their rate and direction of falling. No trees fell within the 2 years following infestation. Thereafter, trees generally fell at the rate of 3-5% per year unless winds exceeded 75mph. Most trees fell to the east and broke off between ground level and 2 feet above ground.

 

Schmid, J.M., Mata, S.A., and Schaupp, Jr., W.C., 2009: Mountain Pine Beetle-Killed Trees as Snags in Black Hills Ponderosa Pine Stands.
ABSTRACT: Mountain pine beetle­killed ponderosa pine trees in three stands of different stocking levels near Bear Mountain in the Black Hills National Forest were surveyed over a 5­year period to determine how long they persisted as unbroken snags. Rate of breakage varied during the first 5 years after MPB infestation: only one tree broke during the first 2years in the three stands? breakage increased during the third year? the highest percentage of snags broke during the fourth year; and 10% to 14% broke in the fifth year. Cumulatively, snag breakage was 76%, 91%, and 95% in a GSL 80/90, GSL 100/110, and unmanaged stand, respectively. On average, 56% of the snags broke below 25 ft. The rate and height ofbreakage in mountain pine beetle­killed trees indicates that they are unlikely to persist as suitable snags for more than 5 to 10 years after infestation.

 

 

Socioeconomic and Policy Research

Flint, C.G., McFarlane, B., and Müller, M., 2008: Human Dimensions of Forest Disturbance by Insects: An International Synthesis. Environmental Management 43(6): 1174-1186.
Abstract: Ecological disturbances of forests by insects have a complex array of associated human dimensions presenting complications for natural resource decision making and relationships between stakeholders and managers. This article discusses the human context of forest disturbances by insects by reviewing four cases of bark beetle forest disturbance from British Columbia in Canada, Bavarian Forest National Park in Germany, the Kenai Peninsula in Alaska, and the north central region of Colorado. Findings and lessons learned from these studies are outlined along with their implications for managing forest disturbances by insects in general. Conclusions focus on the need to assess the broad array of impacts and risks perceived by local residents and the capacity for local action and involvement in managing forest disturbances. Communication and interaction between resource managers and local stakeholders can facilitate the identification of management priorities and potentially reduce some of the risks associated with forest disturbances by insects.

 

Parkins, J.R., 2008: The Metagovernance of Climate Change: Institutional Adaptation to the Mountain Pine Beetle Epidemic in British Columbia. Journal of Rural and Community Development 3(2): 7-26.
ABSTRACT: The interior region of British Columbia is experiencing the most extensive mountain pine beetle outbreak ever recorded in North America, with 9.2 million hectares of red-attach pine forest identified in 2006. The epidemic is attributed to changing climate conditions and forest management policies that have resulted in a large number of mature, even-aged pine trees. Owing to the dominance of the forest industry in this region, there is widespread recognition that the mountain pine beetle outbreak will have significant socioeconomic impacts on forest-based communities in British Columbia. This paper examines the adaptation strategies of several communities that are affected by the mountain pine beetle epidemic. First, drawing from household survey research, latent levels of institutional capacity are discussed. Second, recent institutional adaptations are examined through the emergence of regional-scale beetle action coalitions. These institutional innovations can be characterized as a form of metagovernance, whereby collaboration and negotiated decision making are realized in the context of bureaucratic hierarchy and the extension of state power. The paper concludes with a call for stronger linkages between public and private sectors, as well as more robust forms of civic engagement as the basis for collective response to the mountain pine beetle outbreak.