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• 101. [Article] Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin, USA

  This study analyzed watershed response to climate change and forest fire impacts in the upper Umatilla River Basin (URB), Oregon, using the precipitation runoff modeling system. Ten global climate models ...

  Citation × Citation Citation Abstract Copy Title: Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin, USA Author: Yazzie, Kimberly Crystal, Chang, Heejun Year: 2017 This study analyzed watershed response to climate change and forest fire impacts in the upper Umatilla River Basin (URB), Oregon, using the precipitation runoff modeling system. Ten global climate models using Coupled Intercomparison Project Phase 5 experiments with Representative Concentration Pathways (RCP) 4.5 and 8.5 were used to simulate the effects of climate and fire-burns on runoff behavior throughout the 21st century. We observed the center timing (CT) of flow, seasonal flows, snow water equivalent (SWE) and basin recharge. In the upper URB, hydrologic regime shifts from a snow-rain-dominated to rain-dominated basin. Ensemble mean CT occurs 27 days earlier in RCP 4.5 and 33 days earlier in RCP 8.5, in comparison to historic conditions (1980s) by the end of the 21st century. After forest cover reduction in the 2080s, CT occurs 35 days earlier in RCP 4.5 and 29 days earlier in RCP 8.5. The difference in mean CT after fire-burns may be due to projected changes in the individual climate model. Winter flow is projected to decline after forest cover reduction in the 2080s by 85% and 72% in RCP 4.5 and RCP 8.5, in comparison to 98% change in ensemble mean winter flows in the 2080s before forest cover reduction. The ratio of ensemble mean snow water equivalent to precipitation substantially decreases by 81% and 91% in the 2050s and 2080s before forest cover reduction and a decrease of 90% in RCP 4.5 and 99% in RCP 8.5 in the 2080s after fire-burns. Mean basin recharge is 10% and 14% lower in the 2080s before fire-burns and after fire-burns, and it decreases by 13% in RCP 4.5 and decreases 22% in RCP 8.5 in the 2080s in comparison to historical conditions. Mixed results for recharge after forest cover reduction suggest that an increase may be due to the size of burned areas, decreased canopy interception and less evaporation occurring at the watershed surface, increasing the potential for infiltration. The effects of fire on the watershed system are strongly indicated by a significant increase in winter seasonal flows and a slight reduction in summer flows. Findings from this study may improve adaptive management of water resources, flood control and the effects of fire on a watershed system. Title: Watershed Response to Climate Change and Fire-Burns in the Upper Umatilla River Basin, USA Author: Yazzie, Kimberly Crystal, Chang, Heejun Year: 2017 This study analyzed watershed response to climate change and forest fire impacts in the upper Umatilla River Basin (URB), Oregon, using the precipitation runoff modeling system. Ten global climate models using Coupled Intercomparison Project Phase 5 experiments with Representative Concentration Pathways (RCP) 4.5 and 8.5 were used to simulate the effects of climate and fire-burns on runoff behavior throughout the 21st century. We observed the center timing (CT) of flow, seasonal flows, snow water equivalent (SWE) and basin recharge. In the upper URB, hydrologic regime shifts from a snow-rain-dominated to rain-dominated basin. Ensemble mean CT occurs 27 days earlier in RCP 4.5 and 33 days earlier in RCP 8.5, in comparison to historic conditions (1980s) by the end of the 21st century. After forest cover reduction in the 2080s, CT occurs 35 days earlier in RCP 4.5 and 29 days earlier in RCP 8.5. The difference in mean CT after fire-burns may be due to projected changes in the individual climate model. Winter flow is projected to decline after forest cover reduction in the 2080s by 85% and 72% in RCP 4.5 and RCP 8.5, in comparison to 98% change in ensemble mean winter flows in the 2080s before forest cover reduction. The ratio of ensemble mean snow water equivalent to precipitation substantially decreases by 81% and 91% in the 2050s and 2080s before forest cover reduction and a decrease of 90% in RCP 4.5 and 99% in RCP 8.5 in the 2080s after fire-burns. Mean basin recharge is 10% and 14% lower in the 2080s before fire-burns and after fire-burns, and it decreases by 13% in RCP 4.5 and decreases 22% in RCP 8.5 in the 2080s in comparison to historical conditions. Mixed results for recharge after forest cover reduction suggest that an increase may be due to the size of burned areas, decreased canopy interception and less evaporation occurring at the watershed surface, increasing the potential for infiltration. The effects of fire on the watershed system are strongly indicated by a significant increase in winter seasonal flows and a slight reduction in summer flows. Findings from this study may improve adaptive management of water resources, flood control and the effects of fire on a watershed system. Close

• 102. [Article] North America. Climate Change 2007: Impacts, Adaptation and Vulnerability

  The United States (U.S.) and Canada will experience climate changes through direct effects of local changes (e.g., temperature, precipitation and extreme weather events), as well as through indirect effects, ...

  Citation × Citation Citation Abstract Copy Title: North America. Climate Change 2007: Impacts, Adaptation and Vulnerability Author: Fields, Christopher B., Mortsch, Linda D., Brklacich, Michael, Forbes, Donald L., Kovacs, Paul, Patz, Jonathan A., Running, Steven W., Scott, Michael J., Andrey, Jean, Cayan, Dan, Demuth, Mike, Hamlet, Alan, Jones, Gregory, Mills, Evan, Mills, Scott, Minns, Charles K., Sailor, David J., Saunders, Mark, Scott, Daniel, Solecki, William Year: 2007 The United States (U.S.) and Canada will experience climate changes through direct effects of local changes (e.g., temperature, precipitation and extreme weather events), as well as through indirect effects, transmitted among regions by interconnected economies and migrations of humans and other species. Variations in wealth and geography, however, lead to an uneven distribution of likely impacts, vulnerabilities and capacities to adapt. This chapter reviews and synthesises the state of knowledge on direct and indirect impacts, vulnerability and adaptations for North America (comprising Canada and the U.S). Hawaii and other U.S. protectorates are discussed in Chapter 16 on Small Islands, and Mexico and Central America are treated in Chapter 13 on Latin America. Chapter 15, Polar Regions, covers high-latitude issues and peoples. Title: North America. Climate Change 2007: Impacts, Adaptation and Vulnerability Author: Fields, Christopher B., Mortsch, Linda D., Brklacich, Michael, Forbes, Donald L., Kovacs, Paul, Patz, Jonathan A., Running, Steven W., Scott, Michael J., Andrey, Jean, Cayan, Dan, Demuth, Mike, Hamlet, Alan, Jones, Gregory, Mills, Evan, Mills, Scott, Minns, Charles K., Sailor, David J., Saunders, Mark, Scott, Daniel, Solecki, William Year: 2007 The United States (U.S.) and Canada will experience climate changes through direct effects of local changes (e.g., temperature, precipitation and extreme weather events), as well as through indirect effects, transmitted among regions by interconnected economies and migrations of humans and other species. Variations in wealth and geography, however, lead to an uneven distribution of likely impacts, vulnerabilities and capacities to adapt. This chapter reviews and synthesises the state of knowledge on direct and indirect impacts, vulnerability and adaptations for North America (comprising Canada and the U.S). Hawaii and other U.S. protectorates are discussed in Chapter 16 on Small Islands, and Mexico and Central America are treated in Chapter 13 on Latin America. Chapter 15, Polar Regions, covers high-latitude issues and peoples. Close

• 103. [Article] Trends in streamflow from old growth forested watersheds in the western Cascades

  Increasing temperatures in western North America are expected to result in a decline in winter snowpacks, earlier snowmelt, and a shift in the timing of streamflows, with an increasing fraction of streamflows ...

  Citation × Citation Citation Abstract Copy Title: Trends in streamflow from old growth forested watersheds in the western Cascades Author: Moore, Kathleen M Increasing temperatures in western North America are expected to result in a decline in winter snowpacks, earlier snowmelt, and a shift in the timing of streamflows, with an increasing fraction of streamflows occurring earlier in the water year and drier conditions during the summer. However, few streamflow datasets have associated climate and vegetation records adequate to interpret changes in climate, forest processes, and their consequences for streamflows. This study examined long-term streamflow records from three headwater watersheds in old growth forest at the H. J. Andrews Experimental Forest, Oregon, to seek evidence of trends and investigate possible explanations for these changes. The three small (8.5-60 ha) watersheds (WS2, WS8, and WS9) range in elevation from 432-1182 m and have streamflow records dating back to 1953, 1964, and 1969 respectively. Spring and summer average minimum temperatures have increased over the study period, while April 1st SWE at Santiam Junction has declined significantly. Although precipitation has remained unchanged over the period of study, runoff ratios have declined in spring (March through May) at rates ranging from 25.4% (WS2) to 41.2% (WS8) over the 40- to 50-year periods of streamflow record. Total declines in spring runoff equate to 1.13, 2.13, and 1.23 mm day-1 at WS2, WS8, and WS9, respectively. However, neither winter nor summer runoff ratios have changed significantly, nor has there been a significant shift in the date of water year median flow over the period of record. Winter and spring runoff ratios are negatively related to vapor pressure deficit and/or temperature in the corresponding season, while summer runoff 2 ratios are positively related to vapor pressure deficit and/or temperature. Overall, the findings of this study most strongly support the hypothesis that warming temperatures have resulted in a reduction in spring snowpacks, with an earlier onset of evapotranspiration in the spring and a reduction in evapotranspiration during the summer, due to stomatal closure when VPD becomes sufficiently large or soil moisture becomes limited. Title: Trends in streamflow from old growth forested watersheds in the western Cascades Author: Moore, Kathleen M Increasing temperatures in western North America are expected to result in a decline in winter snowpacks, earlier snowmelt, and a shift in the timing of streamflows, with an increasing fraction of streamflows occurring earlier in the water year and drier conditions during the summer. However, few streamflow datasets have associated climate and vegetation records adequate to interpret changes in climate, forest processes, and their consequences for streamflows. This study examined long-term streamflow records from three headwater watersheds in old growth forest at the H. J. Andrews Experimental Forest, Oregon, to seek evidence of trends and investigate possible explanations for these changes. The three small (8.5-60 ha) watersheds (WS2, WS8, and WS9) range in elevation from 432-1182 m and have streamflow records dating back to 1953, 1964, and 1969 respectively. Spring and summer average minimum temperatures have increased over the study period, while April 1st SWE at Santiam Junction has declined significantly. Although precipitation has remained unchanged over the period of study, runoff ratios have declined in spring (March through May) at rates ranging from 25.4% (WS2) to 41.2% (WS8) over the 40- to 50-year periods of streamflow record. Total declines in spring runoff equate to 1.13, 2.13, and 1.23 mm day-1 at WS2, WS8, and WS9, respectively. However, neither winter nor summer runoff ratios have changed significantly, nor has there been a significant shift in the date of water year median flow over the period of record. Winter and spring runoff ratios are negatively related to vapor pressure deficit and/or temperature in the corresponding season, while summer runoff 2 ratios are positively related to vapor pressure deficit and/or temperature. Overall, the findings of this study most strongly support the hypothesis that warming temperatures have resulted in a reduction in spring snowpacks, with an earlier onset of evapotranspiration in the spring and a reduction in evapotranspiration during the summer, due to stomatal closure when VPD becomes sufficiently large or soil moisture becomes limited. Close

• 104. [Article] Effect of site and silvicultural treatment on insect pests and diseases of young ponderosa pine

  Ponderosa pine is an important species both commercially and ecologically in western North America. This study considers the incidence of insect and disease pests on a series of replicated ponderosa pine ...

  Citation × Citation Citation Abstract Copy Title: Effect of site and silvicultural treatment on insect pests and diseases of young ponderosa pine Author: Norlander, Daniel W. D. Ponderosa pine is an important species both commercially and ecologically in western North America. This study considers the incidence of insect and disease pests on a series of replicated ponderosa pine research plantations in northern California. The studies, on an environmental gradient, contain a series of silvicultural treatments including vegetation control, fertilization application and insecticide application/ thinning. The mean annual temperature and total precipitation were used as climatic variables and the site index was considered as an environmental site variable. Needle retention was negatively correlated to the site productivity, with no treatment affects. Estimates of mean needle retention were in-line with those found in the literature. Total foliar herbivory was the lowest at the highest productivity site, again there were no treatment effects. The gouty pitch midge had the highest level of infestation on the branches of the trees at the site with the lowest productivity. The environmental variables support this with drier, warmer and higher sites being more susceptible. Sequoia pitch moth attacks were highest at the more drier and warmer sites while treatments with vegetation control appear to experience higher levels of attack. Total foliar pathogen infection was the lowest at the highest site index. There was no statistically significant difference between the other five sites and no treatment effect was established. Western gall rust was the highest that the most productive sites and treatments that were fertilized had higher levels of infection. The year of gall infection was associated with the occurrence of El Niño events in the study time period. Title: Effect of site and silvicultural treatment on insect pests and diseases of young ponderosa pine Author: Norlander, Daniel W. D. Ponderosa pine is an important species both commercially and ecologically in western North America. This study considers the incidence of insect and disease pests on a series of replicated ponderosa pine research plantations in northern California. The studies, on an environmental gradient, contain a series of silvicultural treatments including vegetation control, fertilization application and insecticide application/ thinning. The mean annual temperature and total precipitation were used as climatic variables and the site index was considered as an environmental site variable. Needle retention was negatively correlated to the site productivity, with no treatment affects. Estimates of mean needle retention were in-line with those found in the literature. Total foliar herbivory was the lowest at the highest productivity site, again there were no treatment effects. The gouty pitch midge had the highest level of infestation on the branches of the trees at the site with the lowest productivity. The environmental variables support this with drier, warmer and higher sites being more susceptible. Sequoia pitch moth attacks were highest at the more drier and warmer sites while treatments with vegetation control appear to experience higher levels of attack. Total foliar pathogen infection was the lowest at the highest site index. There was no statistically significant difference between the other five sites and no treatment effect was established. Western gall rust was the highest that the most productive sites and treatments that were fertilized had higher levels of infection. The year of gall infection was associated with the occurrence of El Niño events in the study time period. Close

• 105. [Article] Wavelet Analysis of Northeastern United States Climate Data

  59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2...

  Citation × Citation Citation Abstract Copy Title: Wavelet Analysis of Northeastern United States Climate Data Author: Womack, Michael Thomas Year: 2017 59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2017 Title: Wavelet Analysis of Northeastern United States Climate Data Author: Womack, Michael Thomas Year: 2017 59 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Summer 2017 Close

• 106. [Article] Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States

  Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred ...

  Citation × Citation Citation Abstract Copy Title: Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States Author: Heard, Joshua Andrews Year: 2012 Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium line altitude (ELA) of 1995 ± 70 m is ~150 m below the average modern ELA of 2149 ± 76 m. To satisfy climate conditions at the LIA ELA, the winter snow accumulation must have been 8 to 43 cm greater and mean summer temperatures 0.2 to 1.3 ºC cooler than they are now. Late Pleistocene to early Holocene (LPEH) aged moraines are located between 100 and 400 m below the LIA deposits. They have degraded moraine crests, few surface boulders, and considerable vegetation and soil cover. Volcanic ashes indicate LPEH moraines were deposited before 1480 AD while morphometric data suggest deposition during the late Pleistocene or early Holocene. The average LPEH ELA of 1904 ± 110 m is ~ 240 m and ~90 m below the modern and LIA ELAs, respectively. The climate change necessary to maintain a glacier with an ELA at that elevation for LPEH conditions requires the winter accumulation to increase by 47 to 48 cm weq and the mean summer temperature to cool by 1.4 to 1.5 ºC. Last glacial maximum (LGM) moraines are located more than 30 km downstream from modern glacial termini. They are characterized by hummocky topography, rounded moraine crests, complete vegetation cover, and well developed soil cover. Moraine morphometry, soil characteristics, and distance from modern glacial termini indicate that deposition occurred at least 15 ka BP during an expansive cooling event, the last being the LGM. The LGM ELA of 1230 m is ~920 m below the modern ELA. The climate change necessary to maintain a glacier with an ELA at that elevation for LGM conditions requires the mean summer temperature to cool by 5.6 ºC with no change in precipitation. Title: Late Pleistocene and Holocene Aged Glacial and Climatic Reconstructions in the Goat Rocks Wilderness, Washington, United States Author: Heard, Joshua Andrews Year: 2012 Eight glaciers, covering an area of 1.63 km2, reside on the northern and northeastern slopes of the Goat Rocks tallest peaks in the Cascades of central Washington. At least three glacial stands occurred downstream from these glaciers. Closest to modern glacier termini are Little Ice Age (LIA) moraines that were deposited between 1870 and 1899 AD, according to the lichenometric analysis. They are characterized by sharp, minimally eroded crests, little to no soil cover, and minimal vegetation cover. Glacier reconstructions indicate that LIA glaciers covered 8.29 km2, 76% more area than modern ice coverage. The average LIA equilibrium line altitude (ELA) of 1995 ± 70 m is ~150 m below the average modern ELA of 2149 ± 76 m. To satisfy climate conditions at the LIA ELA, the winter snow accumulation must have been 8 to 43 cm greater and mean summer temperatures 0.2 to 1.3 ºC cooler than they are now. Late Pleistocene to early Holocene (LPEH) aged moraines are located between 100 and 400 m below the LIA deposits. They have degraded moraine crests, few surface boulders, and considerable vegetation and soil cover. Volcanic ashes indicate LPEH moraines were deposited before 1480 AD while morphometric data suggest deposition during the late Pleistocene or early Holocene. The average LPEH ELA of 1904 ± 110 m is ~ 240 m and ~90 m below the modern and LIA ELAs, respectively. The climate change necessary to maintain a glacier with an ELA at that elevation for LPEH conditions requires the winter accumulation to increase by 47 to 48 cm weq and the mean summer temperature to cool by 1.4 to 1.5 ºC. Last glacial maximum (LGM) moraines are located more than 30 km downstream from modern glacial termini. They are characterized by hummocky topography, rounded moraine crests, complete vegetation cover, and well developed soil cover. Moraine morphometry, soil characteristics, and distance from modern glacial termini indicate that deposition occurred at least 15 ka BP during an expansive cooling event, the last being the LGM. The LGM ELA of 1230 m is ~920 m below the modern ELA. The climate change necessary to maintain a glacier with an ELA at that elevation for LGM conditions requires the mean summer temperature to cool by 5.6 ºC with no change in precipitation. Close