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• 211. [Article] Tree Vigor Response and Competitive Zone Density in Mature Ponderosa Pine

  This study explored the relationship of mature ponderosa pine (Pinus ponderosa Dougl. ex Laws) tree vigor and competitive zone density following thinning and fuel reduction treatments. Competitive zone ...

  Citation × Citation Citation Abstract Copy Title: Tree Vigor Response and Competitive Zone Density in Mature Ponderosa Pine Author: Shaw, Randi C. This study explored the relationship of mature ponderosa pine (Pinus ponderosa Dougl. ex Laws) tree vigor and competitive zone density following thinning and fuel reduction treatments. Competitive zone density (CZD) was defined as the total tree basal area (m²/ha) surrounding a given ponderosa pine tree within a 10m fixed radius plot. The vigor of 60 trees were observed at two separate mature ponderosa pine stands in south-central Oregon, Lookout Mountain (LM), and Sycan Marsh (SY). Tree vigor response was measured using three physiological metrics: xylem sap flow (kg/day), bole water potential (MPa), and resin exudation (ml/day). Dominant and co-dominant pines were chosen across the available range of CZD at each site. Data were collected over the course of one growing season in 2015, from late June to early October. Sap flow was recorded at four 6-day periods over the season to incorporate the influence of seasonal moisture decline on tree physiological response. Water potential was observed twice, at mid- and late-season. Resin exudation was observed in August to correspond generally with flight periods of various bark beetle species. To account for environmental influences on tree physiology, soil volumetric water content (SWC, m3/m3) was measured approximately every 3-4 weeks and daily potential evapotranspiration (PET) data were obtained from the Western Regional Climate Center’s Remote Access Weather Stations (WRCC RAWS) archives. Data were analyzed using a linear mixed model including both environmental and competitive variables. A quadratic relationship between post-thinning CZD and sap flow was evident, indicating a positive but highly variable association up to a threshold of roughly 40 m²/ha. Above this density threshold sap flow declined markedly, suggesting that tree competition becomes an important factor in constraining water resource access in these sites at higher densities. Bole water potential in mature ponderosa pine was also related to CZD at the LM site. Resin exudation showed disparate relationships to CZD by site and may be more directly influenced by factors other than CZD. Overall tree vigor was higher at LM despite comparatively lower SWC, potentially due to the greater size or age of the study trees. The positive correlation of vigor and CZD up to the middle density range implies that there may be facilitative effects of adjacent trees to be considered for mature ponderosa pine, especially when reducing drought vulnerability is a management goal. Title: Tree Vigor Response and Competitive Zone Density in Mature Ponderosa Pine Author: Shaw, Randi C. This study explored the relationship of mature ponderosa pine (Pinus ponderosa Dougl. ex Laws) tree vigor and competitive zone density following thinning and fuel reduction treatments. Competitive zone density (CZD) was defined as the total tree basal area (m²/ha) surrounding a given ponderosa pine tree within a 10m fixed radius plot. The vigor of 60 trees were observed at two separate mature ponderosa pine stands in south-central Oregon, Lookout Mountain (LM), and Sycan Marsh (SY). Tree vigor response was measured using three physiological metrics: xylem sap flow (kg/day), bole water potential (MPa), and resin exudation (ml/day). Dominant and co-dominant pines were chosen across the available range of CZD at each site. Data were collected over the course of one growing season in 2015, from late June to early October. Sap flow was recorded at four 6-day periods over the season to incorporate the influence of seasonal moisture decline on tree physiological response. Water potential was observed twice, at mid- and late-season. Resin exudation was observed in August to correspond generally with flight periods of various bark beetle species. To account for environmental influences on tree physiology, soil volumetric water content (SWC, m3/m3) was measured approximately every 3-4 weeks and daily potential evapotranspiration (PET) data were obtained from the Western Regional Climate Center’s Remote Access Weather Stations (WRCC RAWS) archives. Data were analyzed using a linear mixed model including both environmental and competitive variables. A quadratic relationship between post-thinning CZD and sap flow was evident, indicating a positive but highly variable association up to a threshold of roughly 40 m²/ha. Above this density threshold sap flow declined markedly, suggesting that tree competition becomes an important factor in constraining water resource access in these sites at higher densities. Bole water potential in mature ponderosa pine was also related to CZD at the LM site. Resin exudation showed disparate relationships to CZD by site and may be more directly influenced by factors other than CZD. Overall tree vigor was higher at LM despite comparatively lower SWC, potentially due to the greater size or age of the study trees. The positive correlation of vigor and CZD up to the middle density range implies that there may be facilitative effects of adjacent trees to be considered for mature ponderosa pine, especially when reducing drought vulnerability is a management goal. Close

• 212. [Article] A critical analysis of wildlife conservation in Oregon

  This analysis is the study of Oregon's wildlife resources from the period prior to white settlement up to the present time, including critical projections, based on present trends and expected conditions for ...

  Citation × Citation Citation Abstract Copy Title: A critical analysis of wildlife conservation in Oregon Author: Rymon, Larry Maring This analysis is the study of Oregon's wildlife resources from the period prior to white settlement up to the present time, including critical projections, based on present trends and expected conditions for both human and wildlife populations in the state up to the year 2010. Prior to white settlement Oregon was apparently part of a well balanced ecosystem. The fertile, moist valley regions were areas where an abundance of wildlife was found. Elk, deer, bear, antelope and their associated predators occupied these favorable sites. The Oregon Indian lived harmoniously within this environment. He conducted himself as a "prudent predator" and generally sought game which was most easily available. These animals were abundant enough to withstand the hunting pressure exerted by the limited Indian population. The only major deliberate control the Indian extended over his environment was burning. Indians ignited large areas to enhance the harvest of wild plants and animals. One of these areas was the Willamette Valley, parts of which were apparently maintained in a condition of fire climax or disclimax long prior to the arrival of white settlers. White pioneers arriving in Oregon in the 1840's settled first in locations where the best agricultural land and available moisture was found. These areas coincided with prime game habitat and the immediate effect of settlement was the displacement of wildlife from their traditional ranges to areas of inferior fertility and moisture. The pattern of development of white civilization had a severe impact on wildlife populations from the late 1800's to the early 1900's. Drainage and reclamation projects coupled with prolonged drought periods drastically reduced waterfowl populations. Excessive killing of game for the meat, hide and feather value further reduced wildlife populations when market hunting reached its peak between 1870 and 1900. Predator and rodent cool efforts were directed toward improving agricultural conditions but often resulted in upsetting previous balances among several forms of wildlife. After 1893 wildlife management evolved through periods of protection, stocking, refuges, and systematic management. The Oregon State Game Commission and the United States Bureau of Biological Survey attempted to work cooperatively with several state and federal agencies in the 1920's and 1930's in an effort to restore depleted wildlife populations. The Taylor Grazing Act helped prevent further mismanagement of rangeland. The Migratory Bird Stamp Act allowed funds for waterfowl habitat purchases. Other legislation such as the Pittman-Robertson Federal Aid to Wildlife Restoration Act is further testimony of Federal Programs which have provided the means for wildlife restoration since the 1930's. The general development of cooperative wildlife research units in the United States together with the formation of Oregon State University's Department of Fisheries and Wildlife were important steps in the movement toward more scientific wildlife management during the 1930's. Several important wildlife management programs were developed in Oregon and successful wildlife restoration programs have continued up to the present time. Although wildlife populations have been largely restored through systematic management, they are again being lost. The next losses will be from severe competition with man for living space and resources. Based on demographic projections and current trends, it appears that the burgeoning human population will eventually cause the annihilation of many wildlife species. Upset watersheds, widespread pollution, increased competition for natural resources, and competition for living space between man and wildlife are unpleasant but real prospects for Oregon's future. Title: A critical analysis of wildlife conservation in Oregon Author: Rymon, Larry Maring This analysis is the study of Oregon's wildlife resources from the period prior to white settlement up to the present time, including critical projections, based on present trends and expected conditions for both human and wildlife populations in the state up to the year 2010. Prior to white settlement Oregon was apparently part of a well balanced ecosystem. The fertile, moist valley regions were areas where an abundance of wildlife was found. Elk, deer, bear, antelope and their associated predators occupied these favorable sites. The Oregon Indian lived harmoniously within this environment. He conducted himself as a "prudent predator" and generally sought game which was most easily available. These animals were abundant enough to withstand the hunting pressure exerted by the limited Indian population. The only major deliberate control the Indian extended over his environment was burning. Indians ignited large areas to enhance the harvest of wild plants and animals. One of these areas was the Willamette Valley, parts of which were apparently maintained in a condition of fire climax or disclimax long prior to the arrival of white settlers. White pioneers arriving in Oregon in the 1840's settled first in locations where the best agricultural land and available moisture was found. These areas coincided with prime game habitat and the immediate effect of settlement was the displacement of wildlife from their traditional ranges to areas of inferior fertility and moisture. The pattern of development of white civilization had a severe impact on wildlife populations from the late 1800's to the early 1900's. Drainage and reclamation projects coupled with prolonged drought periods drastically reduced waterfowl populations. Excessive killing of game for the meat, hide and feather value further reduced wildlife populations when market hunting reached its peak between 1870 and 1900. Predator and rodent cool efforts were directed toward improving agricultural conditions but often resulted in upsetting previous balances among several forms of wildlife. After 1893 wildlife management evolved through periods of protection, stocking, refuges, and systematic management. The Oregon State Game Commission and the United States Bureau of Biological Survey attempted to work cooperatively with several state and federal agencies in the 1920's and 1930's in an effort to restore depleted wildlife populations. The Taylor Grazing Act helped prevent further mismanagement of rangeland. The Migratory Bird Stamp Act allowed funds for waterfowl habitat purchases. Other legislation such as the Pittman-Robertson Federal Aid to Wildlife Restoration Act is further testimony of Federal Programs which have provided the means for wildlife restoration since the 1930's. The general development of cooperative wildlife research units in the United States together with the formation of Oregon State University's Department of Fisheries and Wildlife were important steps in the movement toward more scientific wildlife management during the 1930's. Several important wildlife management programs were developed in Oregon and successful wildlife restoration programs have continued up to the present time. Although wildlife populations have been largely restored through systematic management, they are again being lost. The next losses will be from severe competition with man for living space and resources. Based on demographic projections and current trends, it appears that the burgeoning human population will eventually cause the annihilation of many wildlife species. Upset watersheds, widespread pollution, increased competition for natural resources, and competition for living space between man and wildlife are unpleasant but real prospects for Oregon's future. Close

• 213. [Article] A Landsat time series approach to characterize bark beetle and defoliator impacts on tree mortality and surface fuels in conifer forests

  This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/.

  Citation × Citation Citation Abstract Copy Title: A Landsat time series approach to characterize bark beetle and defoliator impacts on tree mortality and surface fuels in conifer forests Author: Meigs, Garrett W., Cohen, Warren B., Kennedy, Robert E. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Title: A Landsat time series approach to characterize bark beetle and defoliator impacts on tree mortality and surface fuels in conifer forests Author: Meigs, Garrett W., Cohen, Warren B., Kennedy, Robert E. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/. Close

• 214. [Article] Distinguishing between live and dead standing tree biomass on the North Rim of Grand Canyon National Park, USA using small-footprint lidar data

  Accurate estimation of live and dead biomass in forested ecosystems is important for studies of carbon dynamics, biodiversity, and wildfire behavior, and for forest management. Lidar remote sensing has ...

  Citation × Citation Citation Abstract Copy Title: Distinguishing between live and dead standing tree biomass on the North Rim of Grand Canyon National Park, USA using small-footprint lidar data Author: Kim, YunSuk Accurate estimation of live and dead biomass in forested ecosystems is important for studies of carbon dynamics, biodiversity, and wildfire behavior, and for forest management. Lidar remote sensing has been used successfully to estimate live biomass, but studies focusing on dead biomass are rare. We used lidar data, in conjunction with field measurements from 58 plots to distinguish between and map standing live and dead tree biomass in the mixed coniferous forest of the North Rim of Grand Canyon National Park, USA. Lidar intensity and canopy volume were key variables for estimating live biomass, whereas for dead biomass, lidar intensity alone was critical for accurate estimation. Regression estimates of both live and dead biomass ranged between zero and 600 Mg ha⁻¹, with means of 195.08 Mg ha⁻¹ and 65.73 Mg ha⁻¹, respectively. Cross validation with field data resulted in correlation coefficients for predicted vs. observed of 0.85 for live biomass (RMSE = 50 Mg ha⁻¹ and %RMSE (RMSE as a percent of the mean) = 26). For dead biomass, correlation was 0.79, RMSE was 42 Mg ha⁻¹, and %RMSE was 63. Biomass maps revealed interesting patterns of live and dead standing tree biomass. Live biomass was highest in the ponderosa pine zone, and decreased from south to north through the mixed conifer and spruce-fir forest zones. Dead biomass exhibited a background range of values in these mature forests from zero to 100 Mg ha⁻¹, with lower values in locations having higher live biomass. In areas with high dead biomass values, live biomass was near zero. These areas were associated with recent wildfires, as indicated by fire maps derived from the Monitoring Trends in Burn Severity Project (MTBS). Combining our dead biomass maps with the MTBS maps, we demonstrated the complementary power of these two datasets, revealing that MTBS burn intensity class can be described quantitatively in terms of dead biomass. Assuming a background range of dead biomass up to 100 Mg ha⁻¹, it is possible to estimate and map the contribution to the standing dead tree biomass pool associated with recent wildfire. Title: Distinguishing between live and dead standing tree biomass on the North Rim of Grand Canyon National Park, USA using small-footprint lidar data Author: Kim, YunSuk Accurate estimation of live and dead biomass in forested ecosystems is important for studies of carbon dynamics, biodiversity, and wildfire behavior, and for forest management. Lidar remote sensing has been used successfully to estimate live biomass, but studies focusing on dead biomass are rare. We used lidar data, in conjunction with field measurements from 58 plots to distinguish between and map standing live and dead tree biomass in the mixed coniferous forest of the North Rim of Grand Canyon National Park, USA. Lidar intensity and canopy volume were key variables for estimating live biomass, whereas for dead biomass, lidar intensity alone was critical for accurate estimation. Regression estimates of both live and dead biomass ranged between zero and 600 Mg ha⁻¹, with means of 195.08 Mg ha⁻¹ and 65.73 Mg ha⁻¹, respectively. Cross validation with field data resulted in correlation coefficients for predicted vs. observed of 0.85 for live biomass (RMSE = 50 Mg ha⁻¹ and %RMSE (RMSE as a percent of the mean) = 26). For dead biomass, correlation was 0.79, RMSE was 42 Mg ha⁻¹, and %RMSE was 63. Biomass maps revealed interesting patterns of live and dead standing tree biomass. Live biomass was highest in the ponderosa pine zone, and decreased from south to north through the mixed conifer and spruce-fir forest zones. Dead biomass exhibited a background range of values in these mature forests from zero to 100 Mg ha⁻¹, with lower values in locations having higher live biomass. In areas with high dead biomass values, live biomass was near zero. These areas were associated with recent wildfires, as indicated by fire maps derived from the Monitoring Trends in Burn Severity Project (MTBS). Combining our dead biomass maps with the MTBS maps, we demonstrated the complementary power of these two datasets, revealing that MTBS burn intensity class can be described quantitatively in terms of dead biomass. Assuming a background range of dead biomass up to 100 Mg ha⁻¹, it is possible to estimate and map the contribution to the standing dead tree biomass pool associated with recent wildfire. Close

• 215. [Article] Sugar application and nitrogen pools in Wyoming big sagebrush communities and exotic annual grasslands

  Within A rtemisia tridentata ssp. wyomingensis Nutt. (Wyoming big sagebrush) communities of the Great Basin, lands dominated by the exotic annual grass Bromus tectorum L. (cheatgrass) are increasing at ...

  Citation × Citation Citation Abstract Copy Title: Sugar application and nitrogen pools in Wyoming big sagebrush communities and exotic annual grasslands Author: Witwicki, Dana L. Within A rtemisia tridentata ssp. wyomingensis Nutt. (Wyoming big sagebrush) communities of the Great Basin, lands dominated by the exotic annual grass Bromus tectorum L. (cheatgrass) are increasing at an alarming rate. Carbon applications, which reduce plant-available soil N, have been suggested as a way to give native vegetation a competitive advantage over exotic annual grasses when reseeding after a fire. The main objectives of my study were to 1) compare N pools in intact A. tridentata- and B. tectorum-dominated communities to look for evidence of ecosystem changes associated with annual grass invasion, and 2) quantify and compare the effects of sugar and nitrogen additions on N pools in each of these communities. Research occurred at six sites in eastern Oregon and southwestern Idaho, each containing pairs of A. tridentata and exotic annual grass communities in close proximity. Pairs were carefully selected with similar soil types, precipitation, elevation, aspect, slope and ecological sites (i.e. potential vegetation and production). At the beginning of the cheatgrass growing season (late fall), three treatments (sugar, nitrogen or control) were applied. For soil pools, only one difference between untreated plots of annual and native communities was detected. In autumn. NO3 in the native community was about two-thirds the level in the annual community. The sugar treatment decreased inorganic N to near undetectable levels one week after application, and levels remained low six months later (during peak B. tectorum biomass). Although the sugar treatment did not increase microbial biomass N from chloroform fumigation extraction, we found higher '5N in microbial biomass and soil organic matter, suggesting that more N remained in the microbial pooi over the growing season. The reduction of aboveground plant biomass by sugar and the increase of aboveground plant biomass from nitrogen addition were more pronounced for B. tectorum than for native plants. Plant responses indicated that treatment with labile carbon like sugar may be useful tools for restoration of native plants and for prevention of B. tectorum dominance, but additional research is necessary to quantify dose responses of B. tectorum to sugar. Title: Sugar application and nitrogen pools in Wyoming big sagebrush communities and exotic annual grasslands Author: Witwicki, Dana L. Within A rtemisia tridentata ssp. wyomingensis Nutt. (Wyoming big sagebrush) communities of the Great Basin, lands dominated by the exotic annual grass Bromus tectorum L. (cheatgrass) are increasing at an alarming rate. Carbon applications, which reduce plant-available soil N, have been suggested as a way to give native vegetation a competitive advantage over exotic annual grasses when reseeding after a fire. The main objectives of my study were to 1) compare N pools in intact A. tridentata- and B. tectorum-dominated communities to look for evidence of ecosystem changes associated with annual grass invasion, and 2) quantify and compare the effects of sugar and nitrogen additions on N pools in each of these communities. Research occurred at six sites in eastern Oregon and southwestern Idaho, each containing pairs of A. tridentata and exotic annual grass communities in close proximity. Pairs were carefully selected with similar soil types, precipitation, elevation, aspect, slope and ecological sites (i.e. potential vegetation and production). At the beginning of the cheatgrass growing season (late fall), three treatments (sugar, nitrogen or control) were applied. For soil pools, only one difference between untreated plots of annual and native communities was detected. In autumn. NO3 in the native community was about two-thirds the level in the annual community. The sugar treatment decreased inorganic N to near undetectable levels one week after application, and levels remained low six months later (during peak B. tectorum biomass). Although the sugar treatment did not increase microbial biomass N from chloroform fumigation extraction, we found higher '5N in microbial biomass and soil organic matter, suggesting that more N remained in the microbial pooi over the growing season. The reduction of aboveground plant biomass by sugar and the increase of aboveground plant biomass from nitrogen addition were more pronounced for B. tectorum than for native plants. Plant responses indicated that treatment with labile carbon like sugar may be useful tools for restoration of native plants and for prevention of B. tectorum dominance, but additional research is necessary to quantify dose responses of B. tectorum to sugar. Close

• 216. [Article] Creating Useful and Useable Climate Tools for Sagebrush Land Management Through Scientist and Manager Collaboration

  The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation ...

  Citation × Citation Citation Abstract Copy Title: Creating Useful and Useable Climate Tools for Sagebrush Land Management Through Scientist and Manager Collaboration Author: Brown, Melanie The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation and degradation of both quantity and quality due to the cumulative and synergistic relationships between an abundance of individual disturbances including grazing, invasive annuals and fire. Climate change may now be an additional threat that poses the greatest risk to these imperiled habitats. Natural resource agencies such as the Bureau of Land Management (BLM) seek to conserve sagelands through land management activities that ensure the survival of sage-grouse and continuity of the sagebrush biome. Web-based climate tools can help convey climate information that may be necessary for long-term land management, but these tools may not agree with the needs of land managers, may be too complex, or may be misinterpreted. To overcome barriers of user compatibility, the participation of both climate scientists and land managers is necessary during tool development. With the collaboration of Oregon and Idaho BLM sagebrush land managers and climate scientists, this study sought to assess land manager needs and define the criteria for useful and useable climate tools. Using an initial online survey, individual phone interviews with land managers, and a follow-up online survey, a series of land management activities and related climate variables were identified, and several web-based climate tools were assessed. Most managers perform vegetation management through a variety of means including seeding and herbicide application. Such activities are affected by the magnitude and timing of precipitation and temperature, as well as other variables, on seasonal and annual timeframes. For planning purposes land managers also need information on long-term 10-20 year climate trends. The act of listening to the needs of land managers uncovered communication barriers, and provided feedback on existing climate tools emphasizing accessibility, dependability and consistency, clear explanation of terminology, effective visualizations, and relevant spatial and temporal scales to the scope of management activities. We also identified a need for basic information and education on the location of existing climate tools and climate impacts, and a need for near-term forecasting tools that could bridge the gap between weather (≤ 6 months) and climate (≥ 30 years) projections. Keywords: sagebrush, sage-grouse, Oregon State University, climate change, BLM, Oregon, Idaho, Great Basin, land management, collaboration, climate tools Title: Creating Useful and Useable Climate Tools for Sagebrush Land Management Through Scientist and Manager Collaboration Author: Brown, Melanie The sagebrush ecosystem, home to numerous plant and animal species including big sagebrush (Artemisia tridentata) and the endemic greater sage-grouse (Centrocercus urophasianus), has endured fragmentation and degradation of both quantity and quality due to the cumulative and synergistic relationships between an abundance of individual disturbances including grazing, invasive annuals and fire. Climate change may now be an additional threat that poses the greatest risk to these imperiled habitats. Natural resource agencies such as the Bureau of Land Management (BLM) seek to conserve sagelands through land management activities that ensure the survival of sage-grouse and continuity of the sagebrush biome. Web-based climate tools can help convey climate information that may be necessary for long-term land management, but these tools may not agree with the needs of land managers, may be too complex, or may be misinterpreted. To overcome barriers of user compatibility, the participation of both climate scientists and land managers is necessary during tool development. With the collaboration of Oregon and Idaho BLM sagebrush land managers and climate scientists, this study sought to assess land manager needs and define the criteria for useful and useable climate tools. Using an initial online survey, individual phone interviews with land managers, and a follow-up online survey, a series of land management activities and related climate variables were identified, and several web-based climate tools were assessed. Most managers perform vegetation management through a variety of means including seeding and herbicide application. Such activities are affected by the magnitude and timing of precipitation and temperature, as well as other variables, on seasonal and annual timeframes. For planning purposes land managers also need information on long-term 10-20 year climate trends. The act of listening to the needs of land managers uncovered communication barriers, and provided feedback on existing climate tools emphasizing accessibility, dependability and consistency, clear explanation of terminology, effective visualizations, and relevant spatial and temporal scales to the scope of management activities. We also identified a need for basic information and education on the location of existing climate tools and climate impacts, and a need for near-term forecasting tools that could bridge the gap between weather (≤ 6 months) and climate (≥ 30 years) projections. Keywords: sagebrush, sage-grouse, Oregon State University, climate change, BLM, Oregon, Idaho, Great Basin, land management, collaboration, climate tools Close

• 217. [Article] Spatial and ecological analysis of red fir decline in California using FIA data

  Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern ...

  Citation × Citation Citation Abstract Copy Title: Spatial and ecological analysis of red fir decline in California using FIA data Author: Mortenson, Leif A. Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern edges of the northern Californian Coast Ranges, and in the southern Cascades. Red fir commonly grows in pure stands and is often found in association with white fir (Abies concolor), lodgepole pine (Pinus contorta) or Jeffrey pine (Pinus Jeffreyi). Red fir is present in popular recreational areas including Yosemite, Kings Canyon, Sequoia and Lassen Volcanic national parks as well as the Mt. Shasta area and the Lake Tahoe region. Increasing and higher-than-expected red fir mortality and decline over the past five years has been observed in the central Sierra Nevada. This mortality and decline is seen as being caused by a complex interaction of biotic, anthropogenic and abiotic factors. The abiotic factors include drought, climate change (especially decreased snowpack), and the effects of changing fire regimes. The key anthropogenic factors are air pollution and forest management. The biotic factors include red fir dwarf mistletoe (Arceuthobium abietinum f. sp. magnificae), Annosus root disease (Heterobasidion annosum), Cytospora canker (Cytospora abietis), and the fir engraver beetle (Scolytus ventralis). Using USFS Forest Inventory & Analysis (FIA) plots at a density of one every 5.47 km (3.4 miles) across California allowed for the first stand-level analysis of the entire red fir distribution zone in California. The results show that mortality is increasing in red fir, which suggests that at least a short term decline is occurring. The rate at which mortality is increasing varies, depending on which analysis approach is used and decreases if recently burned plots are removed from the analysis. At the individual tree level, red fir mortality (all size classes) is occurring at an annual rate of 2.64%. Red fir dwarf mistletoe is the most significant factor in red fir mortality and decline based on our field observations and statistical analysis. There is a clear visual and statistical difference in forest health between areas that possess red fir dwarf mistletoe and those that don't. This remains true even when stands are heavily stocked and Annosus root disease is present, suggesting that Annosus root disease (which is common throughout the red fir distribution range) is greatly exacerbated by the presence of red fir dwarf mistletoe. Cytospora canker is associated with red fir dwarf mistletoe, and is likely a significant reason why the red fir dwarf mistletoe impacts red fir forest health so significantly. The only variation in spatial pattern of red fir mortality in California is an area of very low red fir mortality around Mt. Shasta (where red fir dwarf mistletoes does not occur). There was not a consistent correlation between red fir mortality and drought stress. The amount of fir engraver activity in California is not well characterized making it difficult to assess its' role in red fir mortality. Title: Spatial and ecological analysis of red fir decline in California using FIA data Author: Mortenson, Leif A. Red fir (Abies magnifica) is a high elevation conifer generally growing between an altitude of 1,400 and 2,700 meters. In California, red fir grows in the Sierra Nevada, the Klamath Mountains, the eastern edges of the northern Californian Coast Ranges, and in the southern Cascades. Red fir commonly grows in pure stands and is often found in association with white fir (Abies concolor), lodgepole pine (Pinus contorta) or Jeffrey pine (Pinus Jeffreyi). Red fir is present in popular recreational areas including Yosemite, Kings Canyon, Sequoia and Lassen Volcanic national parks as well as the Mt. Shasta area and the Lake Tahoe region. Increasing and higher-than-expected red fir mortality and decline over the past five years has been observed in the central Sierra Nevada. This mortality and decline is seen as being caused by a complex interaction of biotic, anthropogenic and abiotic factors. The abiotic factors include drought, climate change (especially decreased snowpack), and the effects of changing fire regimes. The key anthropogenic factors are air pollution and forest management. The biotic factors include red fir dwarf mistletoe (Arceuthobium abietinum f. sp. magnificae), Annosus root disease (Heterobasidion annosum), Cytospora canker (Cytospora abietis), and the fir engraver beetle (Scolytus ventralis). Using USFS Forest Inventory & Analysis (FIA) plots at a density of one every 5.47 km (3.4 miles) across California allowed for the first stand-level analysis of the entire red fir distribution zone in California. The results show that mortality is increasing in red fir, which suggests that at least a short term decline is occurring. The rate at which mortality is increasing varies, depending on which analysis approach is used and decreases if recently burned plots are removed from the analysis. At the individual tree level, red fir mortality (all size classes) is occurring at an annual rate of 2.64%. Red fir dwarf mistletoe is the most significant factor in red fir mortality and decline based on our field observations and statistical analysis. There is a clear visual and statistical difference in forest health between areas that possess red fir dwarf mistletoe and those that don't. This remains true even when stands are heavily stocked and Annosus root disease is present, suggesting that Annosus root disease (which is common throughout the red fir distribution range) is greatly exacerbated by the presence of red fir dwarf mistletoe. Cytospora canker is associated with red fir dwarf mistletoe, and is likely a significant reason why the red fir dwarf mistletoe impacts red fir forest health so significantly. The only variation in spatial pattern of red fir mortality in California is an area of very low red fir mortality around Mt. Shasta (where red fir dwarf mistletoes does not occur). There was not a consistent correlation between red fir mortality and drought stress. The amount of fir engraver activity in California is not well characterized making it difficult to assess its' role in red fir mortality. Close

• 218. [Article] Impacts of fuel reduction thinning treatments on oak and chaparral communities of southwestern Oregon

  In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will ...

  Citation × Citation Citation Abstract Copy Title: Impacts of fuel reduction thinning treatments on oak and chaparral communities of southwestern Oregon Author: Perchemlides, Keith A. In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will these sudden reductions in canopy cover and associated changes in habitat affect native and exotic herbaceous vegetation and canopy species regeneration? Where thinning treatments have both fuel-reduction and ecological restoration objectives, to what extent are these goals compatible? I compared vegetation and abiotic site characteristics between thinned and unthinned chaparral and oak communities of southwestern Oregon where landscape-scale fuel-reduction thinning is occurring. I sampled paired thinned and unthinned transects, established four to seven years post-treatment. I also contrasted impacts of manual vs. mechanical thinning methods, and examined differences in herbaceous composition and responses among canopy community types. Thinning treatments had significant impacts on site conditions and herbaceous cover and composition. Herbaceous cover increased on thinned sites, but species richness and diversity did not change. The strongest differences were decreases in perennial species cover and a near doubling of cover by annual species on thinned sites. While overall proportions of natives and exotics did not change, there were changes at the functional group level. Exotic annual grass cover and the proportion of herbaceous community cover composed of these species increased, while cover by native perennial grasses and regeneration of oaks did not. Cover and proportion of native annual forbs increased more than all other functional groups, while exotic annual forbs and native perennial forbs declined. Herbaceous communities at thinned sites had an early-post-disturbance type of composition dominated by native annual forbs and exotic annual grasses four to seven years after treatments. Re-establishment of native shrubs was sparse in thinned areas, likely due to a lack of fire-stimulated germination. Sites that varied in canopy species composition also supported different herbaceous communities in the absence of thinning, and appeared to respond differently to fuel reduction treatments. Manual and mechanical treatment impacts on abiotic site conditions differed, but their overall impacts on vegetation across canopy community types did not. Treatment type differences in herbaceous responses to thinning were found within some canopy vegetation groups, but sample sizes were small. Results suggest that fuel-reduction thinning may have some unintended negative impacts on oak and chaparral communities of southwestern Oregon. Although treatments have altered fuel conditions, thinning does not appear to have achieved restoration goals and may have substantially changed the composition and regeneration of native perennial communities including canopy species. Continued research and expanded monitoring that account for differences between canopy vegetation communities and treatment types are needed to inform adaptive management in these ecosystems. Title: Impacts of fuel reduction thinning treatments on oak and chaparral communities of southwestern Oregon Author: Perchemlides, Keith A. In response to concerns about excessive stand densities and high-severity wildfires, land managers in the western United States are carrying out extensive programs of fuel reduction thinning. How will these sudden reductions in canopy cover and associated changes in habitat affect native and exotic herbaceous vegetation and canopy species regeneration? Where thinning treatments have both fuel-reduction and ecological restoration objectives, to what extent are these goals compatible? I compared vegetation and abiotic site characteristics between thinned and unthinned chaparral and oak communities of southwestern Oregon where landscape-scale fuel-reduction thinning is occurring. I sampled paired thinned and unthinned transects, established four to seven years post-treatment. I also contrasted impacts of manual vs. mechanical thinning methods, and examined differences in herbaceous composition and responses among canopy community types. Thinning treatments had significant impacts on site conditions and herbaceous cover and composition. Herbaceous cover increased on thinned sites, but species richness and diversity did not change. The strongest differences were decreases in perennial species cover and a near doubling of cover by annual species on thinned sites. While overall proportions of natives and exotics did not change, there were changes at the functional group level. Exotic annual grass cover and the proportion of herbaceous community cover composed of these species increased, while cover by native perennial grasses and regeneration of oaks did not. Cover and proportion of native annual forbs increased more than all other functional groups, while exotic annual forbs and native perennial forbs declined. Herbaceous communities at thinned sites had an early-post-disturbance type of composition dominated by native annual forbs and exotic annual grasses four to seven years after treatments. Re-establishment of native shrubs was sparse in thinned areas, likely due to a lack of fire-stimulated germination. Sites that varied in canopy species composition also supported different herbaceous communities in the absence of thinning, and appeared to respond differently to fuel reduction treatments. Manual and mechanical treatment impacts on abiotic site conditions differed, but their overall impacts on vegetation across canopy community types did not. Treatment type differences in herbaceous responses to thinning were found within some canopy vegetation groups, but sample sizes were small. Results suggest that fuel-reduction thinning may have some unintended negative impacts on oak and chaparral communities of southwestern Oregon. Although treatments have altered fuel conditions, thinning does not appear to have achieved restoration goals and may have substantially changed the composition and regeneration of native perennial communities including canopy species. Continued research and expanded monitoring that account for differences between canopy vegetation communities and treatment types are needed to inform adaptive management in these ecosystems. Close

• 219. [Article] Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial

  Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the ...

  Citation × Citation Citation Abstract Copy Title: Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial Author: Bartels, Marilynn R. Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the few wetland prairies remaining after 150 years of agriculture and urbanization. Sidalcea nelsoniana, listed as threatened under the federal Endangered Species Act, is native to these wetland prairies. The studies described here provide basic information about the habitat requirements and tolerances of S. nelsoniana while testing for the first time the impact of specific management techniques on its growth and reproduction. The effects of prescribed burning and mowing on S. nelsoniana and its habitat were investigated in a field population at W.L. Finley National Wildlife Refuge near Corvallis, Oregon. Measurements of S. nelsoniana and aspects of the surrounding vegetation were recorded during the summer of 1998 within 112 permanent S. nelsoniana-centered quadrats. Burning and mowing treatments were applied in the fall of 1998 and the same measurements of S. nelsoniana and the surrounding vegetation were recorded during the summer of 1999. Treatments had no direct effects on S. nelsoniana performance, but burning and mowing reduced canopy cover, a primary goal of prairie maintenance and restoration. Because perennials often respond slowly to changes in habitat, effects of these manipulations may be more evident in future years. Wetland species may also be sensitive to site hydrology, so maintaining the proper water regime is another important component of wetland prairie management and restoration. A second experimental study evaluated the flooding tolerance of S. nelsoniana. Rhizome fragments were transplanted into pots exposed to four flooding conditions: drained soil, saturated soil with no standing water, standing water from mid-November through mid-April and standing water from mid-November through mid-June. Plants with drained soil died as the spring rains declined, and plants flooded past April died by mid-June. Plants in saturated soils and those flooded until mid-April were most successful. These two treatments most closely match conditions found in Willamette Valley wetland prairies, including S. nelsoniana sites, and suggest that the current distribution of S. nelsoniana approximately matches its hydrologic requirements. Management plans to flood a S. nelsoniana site beyond mid-April might harm this protected species. Title: Conservation of Sidalcea nelsoniana through habitat management : effects of burning, mowing, and altered flooding regime on a rare Willamette Valley perennial Author: Bartels, Marilynn R. Active habitat management plays a key role in the preservation of native ecosystems and rare species, especially in the Willamette Valley of Oregon, where natural succession to woodlands threatens the few wetland prairies remaining after 150 years of agriculture and urbanization. Sidalcea nelsoniana, listed as threatened under the federal Endangered Species Act, is native to these wetland prairies. The studies described here provide basic information about the habitat requirements and tolerances of S. nelsoniana while testing for the first time the impact of specific management techniques on its growth and reproduction. The effects of prescribed burning and mowing on S. nelsoniana and its habitat were investigated in a field population at W.L. Finley National Wildlife Refuge near Corvallis, Oregon. Measurements of S. nelsoniana and aspects of the surrounding vegetation were recorded during the summer of 1998 within 112 permanent S. nelsoniana-centered quadrats. Burning and mowing treatments were applied in the fall of 1998 and the same measurements of S. nelsoniana and the surrounding vegetation were recorded during the summer of 1999. Treatments had no direct effects on S. nelsoniana performance, but burning and mowing reduced canopy cover, a primary goal of prairie maintenance and restoration. Because perennials often respond slowly to changes in habitat, effects of these manipulations may be more evident in future years. Wetland species may also be sensitive to site hydrology, so maintaining the proper water regime is another important component of wetland prairie management and restoration. A second experimental study evaluated the flooding tolerance of S. nelsoniana. Rhizome fragments were transplanted into pots exposed to four flooding conditions: drained soil, saturated soil with no standing water, standing water from mid-November through mid-April and standing water from mid-November through mid-June. Plants with drained soil died as the spring rains declined, and plants flooded past April died by mid-June. Plants in saturated soils and those flooded until mid-April were most successful. These two treatments most closely match conditions found in Willamette Valley wetland prairies, including S. nelsoniana sites, and suggest that the current distribution of S. nelsoniana approximately matches its hydrologic requirements. Management plans to flood a S. nelsoniana site beyond mid-April might harm this protected species. Close

• 220. [Article] Increasing the abundance of rare native wetland prairie species

  Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species ...

  Citation × Citation Citation Abstract Copy Title: Increasing the abundance of rare native wetland prairie species Author: Goodridge, Jennifer, Wilson, Mark V., Clark, Deborah Louise, 1950- Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species are urgently needed, particularly those strategies that promote the regeneration of native species from seed. Fire may be an important factor in promoting regeneration of native species from seed because of its historical role in maintaining the prairie landscape. The study objectives were (1) to determine the effect of prescribed burning on regeneration of native species from seed, and (2) to establish predictive relationships between easily measured plant traits and seedling establishment rates in the field. The general approach was to sow seeds of target wetland prairie species during the fall into experimental field plots already established at the Danebo Wetland, Eugene, OR. Seedling establishment rates were then compared between burned and unburned plots the following spring. To establish predictive relationships these seedling establishment rates were related to selected seed and seedling traits measured under laboratory conditions. Overall seedling establishment rates showed no significant differences between burned (7.0%) and unburned plots (8.7%), although for the seven species showing positive responses to prescribed burning, the increase was approximately doubled in the burned plots. Burning significantly increased the seedling establishment rates of three species, Wyethia angustifolia, Grindelia integrifolia, and Danthonia californica. Seedling establishment significantly decreased with burning for one species, Sidalcea campestris. For three of the four endangered, threatened or rare species, Aster curtus, Horkelia congesta, and Sidalcea cusickii var. purpurea, seedling establishment rates were smaller in the burned plots compared to the unburned plots, although the differences were not significant. Lomatium bradshawii had no seedlings establish in either the burned or the unburned plots. Plant weight 7 days after germination was the best trait at predicting field seedling establishment rates for both the burned plots and the unburned plots, explaining a significant amount of variation in establishment rates: 70% for the burned plots and 45% for the unburned plots. This model could be used by managers to choose species for sowing in burned and unburned prairies or to estimate seeding rates at burned and unburned sites. Title: Increasing the abundance of rare native wetland prairie species Author: Goodridge, Jennifer, Wilson, Mark V., Clark, Deborah Louise, 1950- Native prairies of the Willamette Valley are considered among the rarest of Oregon’s ecosystems and are in critical need of conservation. Management strategies for increasing the abundance of native species are urgently needed, particularly those strategies that promote the regeneration of native species from seed. Fire may be an important factor in promoting regeneration of native species from seed because of its historical role in maintaining the prairie landscape. The study objectives were (1) to determine the effect of prescribed burning on regeneration of native species from seed, and (2) to establish predictive relationships between easily measured plant traits and seedling establishment rates in the field. The general approach was to sow seeds of target wetland prairie species during the fall into experimental field plots already established at the Danebo Wetland, Eugene, OR. Seedling establishment rates were then compared between burned and unburned plots the following spring. To establish predictive relationships these seedling establishment rates were related to selected seed and seedling traits measured under laboratory conditions. Overall seedling establishment rates showed no significant differences between burned (7.0%) and unburned plots (8.7%), although for the seven species showing positive responses to prescribed burning, the increase was approximately doubled in the burned plots. Burning significantly increased the seedling establishment rates of three species, Wyethia angustifolia, Grindelia integrifolia, and Danthonia californica. Seedling establishment significantly decreased with burning for one species, Sidalcea campestris. For three of the four endangered, threatened or rare species, Aster curtus, Horkelia congesta, and Sidalcea cusickii var. purpurea, seedling establishment rates were smaller in the burned plots compared to the unburned plots, although the differences were not significant. Lomatium bradshawii had no seedlings establish in either the burned or the unburned plots. Plant weight 7 days after germination was the best trait at predicting field seedling establishment rates for both the burned plots and the unburned plots, explaining a significant amount of variation in establishment rates: 70% for the burned plots and 45% for the unburned plots. This model could be used by managers to choose species for sowing in burned and unburned prairies or to estimate seeding rates at burned and unburned sites. Close