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• 1. [Article] Coupling snowpack and groundwater dynamics to interpret historical streamflow trends in the western United States

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. The published article is copyrighted by Wiley-Blackwell and can be found at: http:...

  Citation × Citation Citation Abstract Copy Title: Coupling snowpack and groundwater dynamics to interpret historical streamflow trends in the western United States Author: Lewis, Sarah L., Safeeq, Mohammad, Tague, Christina. L., Grant, Gordon E. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. The published article is copyrighted by Wiley-Blackwell and can be found at: http://onlinelibrary.wiley.com/. Title: Coupling snowpack and groundwater dynamics to interpret historical streamflow trends in the western United States Author: Lewis, Sarah L., Safeeq, Mohammad, Tague, Christina. L., Grant, Gordon E. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. The published article is copyrighted by Wiley-Blackwell and can be found at: http://onlinelibrary.wiley.com/. Close

• 2. [Article] Specific consensus statement on the likely impacts of climate change on the Pacific Northwest

  The signatories of this statement seek to describe the state of scientific knowledge regarding likely impacts of climate change to the Pacific Northwest region. The intent is to assist Governor Kulongoski’s ...

  Citation × Citation Citation Abstract Copy Title: Specific consensus statement on the likely impacts of climate change on the Pacific Northwest The signatories of this statement seek to describe the state of scientific knowledge regarding likely impacts of climate change to the Pacific Northwest region. The intent is to assist Governor Kulongoski’s Advisory Group on Global Warming in its task of developing a greenhouse gas emission reduction strategy for Oregon. The signatories agree that climate change is underway and that it is having global effects as well as impacts in the Pacific Northwest region. Title: Specific consensus statement on the likely impacts of climate change on the Pacific Northwest The signatories of this statement seek to describe the state of scientific knowledge regarding likely impacts of climate change to the Pacific Northwest region. The intent is to assist Governor Kulongoski’s Advisory Group on Global Warming in its task of developing a greenhouse gas emission reduction strategy for Oregon. The signatories agree that climate change is underway and that it is having global effects as well as impacts in the Pacific Northwest region. Close

• 3. [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

• 4. [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