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• 1. [Article] Resistance of Selected Wood-Based Materials to Fungal and Termite Attack in Non–Soil Contact Exposures

  The resistance of three naturally durable heartwood species and a stranded giant bamboo product to fungal and termite (Coptotermes formosanus) attack was evaluated at a test site located near Hilo, Hawaii. ...

  Citation × Citation Citation Abstract Copy Title: Resistance of Selected Wood-Based Materials to Fungal and Termite Attack in Non–Soil Contact Exposures Author: Morrell, Jeffrey J. The resistance of three naturally durable heartwood species and a stranded giant bamboo product to fungal and termite (Coptotermes formosanus) attack was evaluated at a test site located near Hilo, Hawaii. Merbau (Intsia bijuga or I. palembanica) and ipe (Tabebuia spp.) were both exceptionally resistant to fungal and termite attack, while western juniper (Juniperus occidentalis) heartwood was slightly less resistant to degradation. The presence of heartwood on western juniper samples had no noticeable effect on the performance of adjacent sapwood. The bamboo decking proved to the least durable of the materials and experienced substantial termite and fungal attack over the 32-month test period. Title: Resistance of Selected Wood-Based Materials to Fungal and Termite Attack in Non–Soil Contact Exposures Author: Morrell, Jeffrey J. The resistance of three naturally durable heartwood species and a stranded giant bamboo product to fungal and termite (Coptotermes formosanus) attack was evaluated at a test site located near Hilo, Hawaii. Merbau (Intsia bijuga or I. palembanica) and ipe (Tabebuia spp.) were both exceptionally resistant to fungal and termite attack, while western juniper (Juniperus occidentalis) heartwood was slightly less resistant to degradation. The presence of heartwood on western juniper samples had no noticeable effect on the performance of adjacent sapwood. The bamboo decking proved to the least durable of the materials and experienced substantial termite and fungal attack over the 32-month test period. Close

• 2. [Article] Resource Selection and Space Use of Western Long-eared Myotis (Myotis evotis) in a Western Juniper (Juniperus occidentalis) Woodland of Central Oregon

  Identifying habitat and spatial requirements of wildlife species across multiple spatial scales is a challenging, yet crucial component of wildlife management. Habitat use of bats is particularly difficult ...

  Citation × Citation Citation Abstract Copy Title: Resource Selection and Space Use of Western Long-eared Myotis (Myotis evotis) in a Western Juniper (Juniperus occidentalis) Woodland of Central Oregon Author: Anthony, Christopher R. (Christopher Ross) Identifying habitat and spatial requirements of wildlife species across multiple spatial scales is a challenging, yet crucial component of wildlife management. Habitat use of bats is particularly difficult to study, and managing habitat to conserve bats is especially challenging because bats are highly vagile organisms that exploit several different types of habitat across many spatio-temporal scales. The status and distribution of bat populations is determined by the spatio-temporal pattern of quality roost sites and foraging areas across the landscape. However, knowledge of these limiting resources for bats and their distribution on the landscape is poorly known in western juniper (Juniperus occidentalis ssp. occidentalis) woodlands, even though at least 16 species of bat occur in these habitats across the western United States. Identifying habitat use by bats in western juniper woodlands is especially important due to recent landscape-scale efforts to remove juniper trees to improve habitat for greater sage-grouse (Centrocercus urophasianus), a species of major conservation concern in shrub-steppe habitats. Thus, the urgent challenge for land management agencies in western North America is to identify bat day roost and foraging sites in order to develop management guidelines to conserve bats and their critical habitats. The specific objective of this study was to identify habitat characteristics that are important to western long-eared myotis (Myotis evotis) during the reproductive season in western juniper woodland of central Oregon. I used radio telemetry to find day roost sites and investigate selection criteria for these sites by lactating female and male bats. I studied day roost site selection at three spatial scales: roost, plot, and home range. I found that females prefer to roost in rocks rather than in trees, whereas males did not display a preference towards either type of roost substrate. Bats that roosted in trees used primarily pre-settlement junipers (> 150 years old) with at least one cavity, and bats that roosted in rocks used primarily formations consisting on multiple boulders. More available roost sites within 17.8 m of a tree roost site (or within 5 m of a rock roost site) was associated with an increased likelihood that a particular tree or rock roost site was selected. Males selected rock roosts that had greater area of pre-settlement woodlands than shrub-steppe within a 1 km radius. These results suggest that roost site selection differs between lactating females and males and occurs at multiple spatial scales. Land management practices that retain pre-settlement trees during juniper removal treatments and protect areas with high densities of roost sites near water sources are likely to conserve or restore bat populations. I also estimated home range size and the maximum foraging range of bats. Estimates of mean home range size were the largest ever reported for western long-eared myotis and among the largest for any Myotis species so far studied in North America. The mean 95% home range size for lactating females was 205.85 ha (SE = 47.94) and for males was 424.2 ha (SE = 187.2). The mean maximum foraging range for lactating females was 933 m (SE = 284.9) and males was 1522 m (SE = 532.8). Estimates of mean home range size and maximum foraging range did not differ between lactating females and males; however, low statistical power likely precluded detecting a difference. Lastly, I examined habitat selection at two spatial scales, (1) home range selection on the landscape scale and (2) foraging habitat selection within the home range. The probability of a location being selected by either lactating female or male bats decreased with increasing distance from day roost sites and water sources. Lactating females selected pre-settlement woodlands more than shrub-steppe habitat during foraging, but avoided areas with > 20% tree canopy cover more than areas with no canopy cover at the landscape scale. Males selected areas with 0.1% to 10% tree canopy cover more than areas with no canopy cover at the home range scale. To maintain foraging habitat for M. evotis in the study area, pre-settlement woodlands that are located near roost sites and water sources should be managed for variable tree densities. Title: Resource Selection and Space Use of Western Long-eared Myotis (Myotis evotis) in a Western Juniper (Juniperus occidentalis) Woodland of Central Oregon Author: Anthony, Christopher R. (Christopher Ross) Identifying habitat and spatial requirements of wildlife species across multiple spatial scales is a challenging, yet crucial component of wildlife management. Habitat use of bats is particularly difficult to study, and managing habitat to conserve bats is especially challenging because bats are highly vagile organisms that exploit several different types of habitat across many spatio-temporal scales. The status and distribution of bat populations is determined by the spatio-temporal pattern of quality roost sites and foraging areas across the landscape. However, knowledge of these limiting resources for bats and their distribution on the landscape is poorly known in western juniper (Juniperus occidentalis ssp. occidentalis) woodlands, even though at least 16 species of bat occur in these habitats across the western United States. Identifying habitat use by bats in western juniper woodlands is especially important due to recent landscape-scale efforts to remove juniper trees to improve habitat for greater sage-grouse (Centrocercus urophasianus), a species of major conservation concern in shrub-steppe habitats. Thus, the urgent challenge for land management agencies in western North America is to identify bat day roost and foraging sites in order to develop management guidelines to conserve bats and their critical habitats. The specific objective of this study was to identify habitat characteristics that are important to western long-eared myotis (Myotis evotis) during the reproductive season in western juniper woodland of central Oregon. I used radio telemetry to find day roost sites and investigate selection criteria for these sites by lactating female and male bats. I studied day roost site selection at three spatial scales: roost, plot, and home range. I found that females prefer to roost in rocks rather than in trees, whereas males did not display a preference towards either type of roost substrate. Bats that roosted in trees used primarily pre-settlement junipers (> 150 years old) with at least one cavity, and bats that roosted in rocks used primarily formations consisting on multiple boulders. More available roost sites within 17.8 m of a tree roost site (or within 5 m of a rock roost site) was associated with an increased likelihood that a particular tree or rock roost site was selected. Males selected rock roosts that had greater area of pre-settlement woodlands than shrub-steppe within a 1 km radius. These results suggest that roost site selection differs between lactating females and males and occurs at multiple spatial scales. Land management practices that retain pre-settlement trees during juniper removal treatments and protect areas with high densities of roost sites near water sources are likely to conserve or restore bat populations. I also estimated home range size and the maximum foraging range of bats. Estimates of mean home range size were the largest ever reported for western long-eared myotis and among the largest for any Myotis species so far studied in North America. The mean 95% home range size for lactating females was 205.85 ha (SE = 47.94) and for males was 424.2 ha (SE = 187.2). The mean maximum foraging range for lactating females was 933 m (SE = 284.9) and males was 1522 m (SE = 532.8). Estimates of mean home range size and maximum foraging range did not differ between lactating females and males; however, low statistical power likely precluded detecting a difference. Lastly, I examined habitat selection at two spatial scales, (1) home range selection on the landscape scale and (2) foraging habitat selection within the home range. The probability of a location being selected by either lactating female or male bats decreased with increasing distance from day roost sites and water sources. Lactating females selected pre-settlement woodlands more than shrub-steppe habitat during foraging, but avoided areas with > 20% tree canopy cover more than areas with no canopy cover at the landscape scale. Males selected areas with 0.1% to 10% tree canopy cover more than areas with no canopy cover at the home range scale. To maintain foraging habitat for M. evotis in the study area, pre-settlement woodlands that are located near roost sites and water sources should be managed for variable tree densities. Close

• 3. [Article] Lateral Edge Connection and Withdrawal Capacity of Western Juniper

  Western juniper (Juniperus occidentalis) is a “native invasive” tree species in Eastern Oregon. It is extremely good at finding and consuming water in arid climates, which makes it difficult for other ...

  Citation × Citation Citation Abstract Copy Title: Lateral Edge Connection and Withdrawal Capacity of Western Juniper Author: Girod, Hayley E. Western juniper (Juniperus occidentalis) is a “native invasive” tree species in Eastern Oregon. It is extremely good at finding and consuming water in arid climates, which makes it difficult for other plant species, especially sagebrush and grasses to survive. Sagebrush and grasses are necessary for the survival of the sage grouse, a threatened species. There is much discussion about harvesting juniper trees to help alleviate the stresses the trees put on the sage grouse and water supply in Eastern Oregon. However, there is not much of a market for juniper wood. Part of the reason is that there are no design values for juniper available, making engineers and designers reluctant to choose juniper for structural applications. The goal of this project is to increase the amount of available information about juniper wood in order to encourage its use in structural applications. To contribute to this goal, this project evaluated the performance of connections involving Western juniper wood and other common wood-based building materials. The tests for this project will include edge lateral nail connection test as per ASTM D 1575, dowel bearing strength test as per ASTM D 5764, and withdrawal test as per ASTM D 1761. Following the testing, the data was analyzed and inferences were drawn about the performance of the species in these types of connections. The results were also evaluated against predictive design equations found in the National Design Specification. The result of this project will help form a material statistic on performance of connections involving western juniper. Western juniper can potentially be an economically important species for rural Eastern Oregon. However, lack of engineering design values for the species and a performance metric for connections impedes its acceptance in mainstream construction. The data obtained in this study suggests that NDS equations can adequately predict connection performance of juniper, provided the specific gravity is known. Title: Lateral Edge Connection and Withdrawal Capacity of Western Juniper Author: Girod, Hayley E. Western juniper (Juniperus occidentalis) is a “native invasive” tree species in Eastern Oregon. It is extremely good at finding and consuming water in arid climates, which makes it difficult for other plant species, especially sagebrush and grasses to survive. Sagebrush and grasses are necessary for the survival of the sage grouse, a threatened species. There is much discussion about harvesting juniper trees to help alleviate the stresses the trees put on the sage grouse and water supply in Eastern Oregon. However, there is not much of a market for juniper wood. Part of the reason is that there are no design values for juniper available, making engineers and designers reluctant to choose juniper for structural applications. The goal of this project is to increase the amount of available information about juniper wood in order to encourage its use in structural applications. To contribute to this goal, this project evaluated the performance of connections involving Western juniper wood and other common wood-based building materials. The tests for this project will include edge lateral nail connection test as per ASTM D 1575, dowel bearing strength test as per ASTM D 5764, and withdrawal test as per ASTM D 1761. Following the testing, the data was analyzed and inferences were drawn about the performance of the species in these types of connections. The results were also evaluated against predictive design equations found in the National Design Specification. The result of this project will help form a material statistic on performance of connections involving western juniper. Western juniper can potentially be an economically important species for rural Eastern Oregon. However, lack of engineering design values for the species and a performance metric for connections impedes its acceptance in mainstream construction. The data obtained in this study suggests that NDS equations can adequately predict connection performance of juniper, provided the specific gravity is known. Close

• 4. [Article] Vegetation and Small Mammal Responses to Western Juniper (Juniperus occidentalis) Control in Eastern Oregon

  Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions ...

  Citation × Citation Citation Abstract Copy Title: Vegetation and Small Mammal Responses to Western Juniper (Juniperus occidentalis) Control in Eastern Oregon Author: Morozumi, Corinne N. Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions of people. They are some of the most vulnerable ecosystems in the United States and have been altered by human activities such as livestock grazing, active fire suppression, conversion to agriculture, and urbanization of the west. Since the late 1800s woody encroachment of piñon-juniper species has also contributed to the loss of shrub-steppe habitat. Presently, land managers remove woody tree species in order to recover shrub-steppe although it is unclear how responses to these management activities differ due to site-specific conditions and existing woodland development. I studied post juniper-thinning responses in eastern Oregon at a wildlife area important as winter range for mule deer (Odocoileus hemionus). I investigated vegetative responses to western juniper (Juniperus occidentalis) thinning across a woodland development gradient and tested for interactive effects of juniper cutting and cattle exclusion. In addition, I explored plant and small mammal successional dynamics after juniper thinning and examined plant community responses within microhabitats created by the felled trees. I compared vegetative responses to juniper thinning as well as cattle exclusion among sites where juniper were subordinate (Phase I), co-dominant (Phase II), and dominant to shrubs and grasses (Phase III, sensu Miller et al. 2005). At the Phase I site, thinning did not increase herbaceous biomass while thinned plots at the Phase II site had 2.71 times more median herbaceous biomass (99.17% CI: 1.37 to 5.37 times more biomass) than unthinned plots. Conversely, herbaceous biomass at the Phase III juniper woodland site was 0.36 times lower in thinned plots when compared to unthinned plots (99.17% CI: 0.17 to 0.78 times less biomass). Unfortunately, many of the responses were driven by exotic species release. Where juniper were subordinate (Phase I), mean percent cover by exotic grass increased by 24.58 percentage points in thinned plots as compared to unthinned plots (98.30% CI: 0.27 to 48.90 percentage points higher). Thinning at the Phase II site increased mean exotic grass cover by an estimated 28.47 percentage points as compared to mean exotic cover in the same plots before treatment (98.30% CI: 4.15 to 52.79 percentage points higher cover). Median native bunchgrass cover at this site was 5.06 times greater after juniper treatment (99.7% CI: 1.78 to 14.35 times higher percent cover). I found few main or interactive effects of cattle exclosure after one year of treatment. Responses to grazing exclosure may take longer to develop. These results indicate that sites within the wildlife area respond differently to juniper management and that exotic grass control will be key to successful shrub-steppe recovery. In addition, I used a time-since-juniper thinning chronoseries consisting of plots cut in 2008, 2009, 2010, 2012, and an adjacent uncut control to explore how shrub-steppe flora and fauna are responding to juniper treatment through time. Shrub cover and seedling density were low in each plot. I recorded the highest seedling abundance (mean of 0.25 seedlings) in the uncut control plot. Median grass cover in the uncut control was 9.50% while in the most recently treated plot (2012) it was 26.75%. Small mammal relative abundance and diversity was low across all time-since-treatment plots though highest in the plot with the greatest time-since-treatment. Deer mouse (Peromyscus maniculatus) was the most abundant species in all plots and accounted for 70-95% of all unique captures. Least chipmunk (Tamias minimus) were present in the plot with greatest time-since-treatment indicating the potential recovery of key native shrubs since these small mammals perform an important seed dispersal role. I also investigated how potential microhabitats created by the felled juniper might support different plant communities. I assessed plant responses within zones created by 1) the felled tree (canopy zone), 2) the original duff zone, and 3) the between - tree interspace zone. The three zones had different plant community compositions as analyzed multivariately with non-metric multidimensional scaling (NMS). Canopy and duff zones were forb - dominated and had less exotic grass invasion while interspace zones were heavily invested with medusahead (Taeniatherum caput-medusae) and ventenata (Ventenata dubia). Exotic herbaceous productivity was lowest under the standing trees of the control plot and high in the interspace of all plots with juniper thinning. In the 2012 cut plot, grass cover was 27.90 percentage points less in the canopy zone compared to the interspace zone (98.75% CI: 17.64 to 38.16 percentage points less grass cover). In the uncut control, median native biomass was 2.08 times greater under the standing trees compared to the interspace (96.25% CI: 1.09 to 3.97 times more biomass). Results from the time-since-treatment chronoseries indicated that exotic grass dominance might be limiting shrub-steppe recovery. Active restoration of shrubs and native grasses may be necessary to address the dominance of exotic grass after juniper thinning. Positive signs of habitat recovery included small mammal responses though I was unable to calculate population estimates due to plot size. Title: Vegetation and Small Mammal Responses to Western Juniper (Juniperus occidentalis) Control in Eastern Oregon Author: Morozumi, Corinne N. Shrub-steppe ecosystems of western North America provide habitat for many wildlife species, are important components of public and private rangelands, and offer recreational opportunities for millions of people. They are some of the most vulnerable ecosystems in the United States and have been altered by human activities such as livestock grazing, active fire suppression, conversion to agriculture, and urbanization of the west. Since the late 1800s woody encroachment of piñon-juniper species has also contributed to the loss of shrub-steppe habitat. Presently, land managers remove woody tree species in order to recover shrub-steppe although it is unclear how responses to these management activities differ due to site-specific conditions and existing woodland development. I studied post juniper-thinning responses in eastern Oregon at a wildlife area important as winter range for mule deer (Odocoileus hemionus). I investigated vegetative responses to western juniper (Juniperus occidentalis) thinning across a woodland development gradient and tested for interactive effects of juniper cutting and cattle exclusion. In addition, I explored plant and small mammal successional dynamics after juniper thinning and examined plant community responses within microhabitats created by the felled trees. I compared vegetative responses to juniper thinning as well as cattle exclusion among sites where juniper were subordinate (Phase I), co-dominant (Phase II), and dominant to shrubs and grasses (Phase III, sensu Miller et al. 2005). At the Phase I site, thinning did not increase herbaceous biomass while thinned plots at the Phase II site had 2.71 times more median herbaceous biomass (99.17% CI: 1.37 to 5.37 times more biomass) than unthinned plots. Conversely, herbaceous biomass at the Phase III juniper woodland site was 0.36 times lower in thinned plots when compared to unthinned plots (99.17% CI: 0.17 to 0.78 times less biomass). Unfortunately, many of the responses were driven by exotic species release. Where juniper were subordinate (Phase I), mean percent cover by exotic grass increased by 24.58 percentage points in thinned plots as compared to unthinned plots (98.30% CI: 0.27 to 48.90 percentage points higher). Thinning at the Phase II site increased mean exotic grass cover by an estimated 28.47 percentage points as compared to mean exotic cover in the same plots before treatment (98.30% CI: 4.15 to 52.79 percentage points higher cover). Median native bunchgrass cover at this site was 5.06 times greater after juniper treatment (99.7% CI: 1.78 to 14.35 times higher percent cover). I found few main or interactive effects of cattle exclosure after one year of treatment. Responses to grazing exclosure may take longer to develop. These results indicate that sites within the wildlife area respond differently to juniper management and that exotic grass control will be key to successful shrub-steppe recovery. In addition, I used a time-since-juniper thinning chronoseries consisting of plots cut in 2008, 2009, 2010, 2012, and an adjacent uncut control to explore how shrub-steppe flora and fauna are responding to juniper treatment through time. Shrub cover and seedling density were low in each plot. I recorded the highest seedling abundance (mean of 0.25 seedlings) in the uncut control plot. Median grass cover in the uncut control was 9.50% while in the most recently treated plot (2012) it was 26.75%. Small mammal relative abundance and diversity was low across all time-since-treatment plots though highest in the plot with the greatest time-since-treatment. Deer mouse (Peromyscus maniculatus) was the most abundant species in all plots and accounted for 70-95% of all unique captures. Least chipmunk (Tamias minimus) were present in the plot with greatest time-since-treatment indicating the potential recovery of key native shrubs since these small mammals perform an important seed dispersal role. I also investigated how potential microhabitats created by the felled juniper might support different plant communities. I assessed plant responses within zones created by 1) the felled tree (canopy zone), 2) the original duff zone, and 3) the between - tree interspace zone. The three zones had different plant community compositions as analyzed multivariately with non-metric multidimensional scaling (NMS). Canopy and duff zones were forb - dominated and had less exotic grass invasion while interspace zones were heavily invested with medusahead (Taeniatherum caput-medusae) and ventenata (Ventenata dubia). Exotic herbaceous productivity was lowest under the standing trees of the control plot and high in the interspace of all plots with juniper thinning. In the 2012 cut plot, grass cover was 27.90 percentage points less in the canopy zone compared to the interspace zone (98.75% CI: 17.64 to 38.16 percentage points less grass cover). In the uncut control, median native biomass was 2.08 times greater under the standing trees compared to the interspace (96.25% CI: 1.09 to 3.97 times more biomass). Results from the time-since-treatment chronoseries indicated that exotic grass dominance might be limiting shrub-steppe recovery. Active restoration of shrubs and native grasses may be necessary to address the dominance of exotic grass after juniper thinning. Positive signs of habitat recovery included small mammal responses though I was unable to calculate population estimates due to plot size. Close

• 5. [Article] Estimating a juniper biomass supply from private rangelands : the impact of distance and biotic factors on costs

  Central Oregon has attracted attention as a potential location for a biomass industry based on a locally fixed source of western juniper (Juniperus occidentalis Hook) feedstock. This study identifies ...

  Citation × Citation Citation Abstract Copy Title: Estimating a juniper biomass supply from private rangelands : the impact of distance and biotic factors on costs Author: McCaulou, Jeff, C. Central Oregon has attracted attention as a potential location for a biomass industry based on a locally fixed source of western juniper (Juniperus occidentalis Hook) feedstock. This study identifies a supply of juniper from private lands to determine how much of the available juniper is economically supplied at alternative prices if a market were to develop. In light of the encroachment of juniper and its spillover costs, the potential benefits of removal may be multi-dimensional in terms of private benefits to landowners, as well as social benefits from water and habitat enhancement. At current density, juniper on these private lands has negative impacts that diminish biodiversity, reduce forage grass and tie up water resources to some degree. The difference in the value of cattle productivity resulting from the presence of juniper as well as any forgone net returns from the sale of juniper to the biofuel industry reflect the opportunity cost to the rancher. The supply curve for juniper as a biofuel source will shift in response to policy and economic factors. For example, the Oregon Biofuel Producer tax credit and a federal wildlife enhancement program augment the acre level harvest costs, and thus shift supply. In this research, the components of cost are estimated. The average total cost for extraction, processing, and transporting the entire quantity is estimated to be approximately $120 bdt⁻¹. On a per land acre basis the costs will vary by density. Because of limited road networks the available supply of juniper was limited by access --only 27 percent of the juniper acres on private rangelands. Thus in the absence of an improved road network, economically viable juniper to supply the biofuel market is limited. Given the relatively low prices being discussed by the industry, the feasibility of supplying juniper at a scale needed for a biofuel facility is unlikely. The potential increases in cattle production due to juniper removal could reduce costs by 20 percent, but this is not likely to substantially increase the quantities supplied. Other possible shifters of the supply curve for juniper include subsidies, technological improvements in harvesting, and road building. Title: Estimating a juniper biomass supply from private rangelands : the impact of distance and biotic factors on costs Author: McCaulou, Jeff, C. Central Oregon has attracted attention as a potential location for a biomass industry based on a locally fixed source of western juniper (Juniperus occidentalis Hook) feedstock. This study identifies a supply of juniper from private lands to determine how much of the available juniper is economically supplied at alternative prices if a market were to develop. In light of the encroachment of juniper and its spillover costs, the potential benefits of removal may be multi-dimensional in terms of private benefits to landowners, as well as social benefits from water and habitat enhancement. At current density, juniper on these private lands has negative impacts that diminish biodiversity, reduce forage grass and tie up water resources to some degree. The difference in the value of cattle productivity resulting from the presence of juniper as well as any forgone net returns from the sale of juniper to the biofuel industry reflect the opportunity cost to the rancher. The supply curve for juniper as a biofuel source will shift in response to policy and economic factors. For example, the Oregon Biofuel Producer tax credit and a federal wildlife enhancement program augment the acre level harvest costs, and thus shift supply. In this research, the components of cost are estimated. The average total cost for extraction, processing, and transporting the entire quantity is estimated to be approximately $120 bdt⁻¹. On a per land acre basis the costs will vary by density. Because of limited road networks the available supply of juniper was limited by access --only 27 percent of the juniper acres on private rangelands. Thus in the absence of an improved road network, economically viable juniper to supply the biofuel market is limited. Given the relatively low prices being discussed by the industry, the feasibility of supplying juniper at a scale needed for a biofuel facility is unlikely. The potential increases in cattle production due to juniper removal could reduce costs by 20 percent, but this is not likely to substantially increase the quantities supplied. Other possible shifters of the supply curve for juniper include subsidies, technological improvements in harvesting, and road building. Close

• 6. [Article] Spatial and age class analysis of managed western juniper (Juniperus occidentalis) woodlands in central Oregon

  Juniper is a native species to Oregon and confers ecological benefits to wildlife when it is at savannah and transitional densities. Its range and extent have fluctuated with climatic change, but the current ...

  Citation × Citation Citation Abstract Copy Title: Spatial and age class analysis of managed western juniper (Juniperus occidentalis) woodlands in central Oregon Author: Zophy, Kelley T. Juniper is a native species to Oregon and confers ecological benefits to wildlife when it is at savannah and transitional densities. Its range and extent have fluctuated with climatic change, but the current range expansion is unprecedented in its extent. The range expansion has been associated with the degradation of the sagebrush steppe ecosystem in central Oregon. In the past, attempts to restore the sagebrush-steppe from western juniper aforestation were motivated by the desire to improve forage quality. Currently western juniper management is wider in scope, encompassing social, ecological, and environmental objectives. Past research in the area of western juniper management focused extensively on the causes of western juniper aforestation, its impact on understory plant communities, soil and the water budget. Researchers have also explored multiple mechanisms for removing western juniper and have quantified resulting amelioration of ecosystem function. However little work has been done identifying topographical features or environmental conditions that may influence the density of western juniper woodlands and seedling reestablishment following the application of treatment regimes. This study used spatial modeling to explore the influence that elevation and direct incident radiance have on western juniper density and multivariate, nonparametric tools to identify relationships between topography, understory plant community and seedling reestablishment on managed sites. The study findings indicate that western juniper densities in central Oregon are influenced by topographical features in the landscape. The multivariate analysis revealed that seedling reestablishment is positively associated with the diversity of the understory plant community. The study also revealed that on almost all of the sites included in the study, western juniper seedling are reestablishing after treatment application. With the information generated in the study, managers have tools with which to assess the risk a region has to be dominated by western juniper woodlands. Managers can then efficiently allocate western juniper management resources by choosing to treat that sites that have both the greatest risk and the greatest capacity to meet their objectives. Title: Spatial and age class analysis of managed western juniper (Juniperus occidentalis) woodlands in central Oregon Author: Zophy, Kelley T. Juniper is a native species to Oregon and confers ecological benefits to wildlife when it is at savannah and transitional densities. Its range and extent have fluctuated with climatic change, but the current range expansion is unprecedented in its extent. The range expansion has been associated with the degradation of the sagebrush steppe ecosystem in central Oregon. In the past, attempts to restore the sagebrush-steppe from western juniper aforestation were motivated by the desire to improve forage quality. Currently western juniper management is wider in scope, encompassing social, ecological, and environmental objectives. Past research in the area of western juniper management focused extensively on the causes of western juniper aforestation, its impact on understory plant communities, soil and the water budget. Researchers have also explored multiple mechanisms for removing western juniper and have quantified resulting amelioration of ecosystem function. However little work has been done identifying topographical features or environmental conditions that may influence the density of western juniper woodlands and seedling reestablishment following the application of treatment regimes. This study used spatial modeling to explore the influence that elevation and direct incident radiance have on western juniper density and multivariate, nonparametric tools to identify relationships between topography, understory plant community and seedling reestablishment on managed sites. The study findings indicate that western juniper densities in central Oregon are influenced by topographical features in the landscape. The multivariate analysis revealed that seedling reestablishment is positively associated with the diversity of the understory plant community. The study also revealed that on almost all of the sites included in the study, western juniper seedling are reestablishing after treatment application. With the information generated in the study, managers have tools with which to assess the risk a region has to be dominated by western juniper woodlands. Managers can then efficiently allocate western juniper management resources by choosing to treat that sites that have both the greatest risk and the greatest capacity to meet their objectives. Close

• 7. [Article] Climate-growth relationships of western juniper and ponderosa pine at the pine-woodland ecotone in southern Oregon

  Pinyon-juniper woodlands throughout the western U.S. have expanded rapidly following European settlement during the late 19th century. In central and eastern Oregon, western juniper (Juniperus occidentalis ...

  Citation × Citation Citation Abstract Copy Title: Climate-growth relationships of western juniper and ponderosa pine at the pine-woodland ecotone in southern Oregon Author: Knutson, Kevin C. Pinyon-juniper woodlands throughout the western U.S. have expanded rapidly following European settlement during the late 19th century. In central and eastern Oregon, western juniper (Juniperus occidentalis var. occidentalis Hook.) encroachment has been previously documented in the sagebrush steppe and upper elevation aspen communities. While these vegetation changes and dynamics have been extensively studied, the ability to accurately predict future effects on vegetation structure in response to climatic effects requires the identification of climatic factors that most directly regulate growth across variations in spatial features, particularly when future climate change is likely. I sought to address this problem at the pine-woodland ecotone using tree-ring data for western juniper and ponderosa pine (Pinus ponderosa Dougl. Ex Loud.) from the Fremont National Forest of central Oregon. Site and soil-derived growth chronologies for the period 1950 to 2000 were developed for both species using standard dendrochronological techniques at 17 sites within the Fremont National Forest stratified by elevation (1584 and 1865 meters). Analysis of the climatic relationship with site and soil-derived chronologies using correlation and linear regression revealed that, similar to previous studies in Oregon, radial growth in both species is highly dependent on winter-spring precipitation events that recharge growing-season soil water. Ordinations of site- and soil-derived chronology principal components (PCA) scores for both species identified distinct gradients in growth patterns related to elevation, slope, and soil infiltration class. Low elevation sites had reduced growth in the nine driest years during 1950-2000 compared to high elevation sites. Slope was also positively associated with the ratio of standardized growth in wet years to dry years (W:D), a measure of climate sensitivity. Tree growth of both species on coarse-textured soils with rapid infiltration rates was more climate-sensitive (higher values of W:D) and was also reduced during drought years when compared to other infiltration classes. These findings suggest potentially significant variation in growth responses to future climate changes across distinct local features at the pine-woodland ecotone. Juniper and pine radial growth at sites that feature poor water-holding capacities (i.e., low elevation, steep slopes, and coarse-textured soils) can be expected to be most sensitive to future drought and climate fluctuations in southern Oregon. Title: Climate-growth relationships of western juniper and ponderosa pine at the pine-woodland ecotone in southern Oregon Author: Knutson, Kevin C. Pinyon-juniper woodlands throughout the western U.S. have expanded rapidly following European settlement during the late 19th century. In central and eastern Oregon, western juniper (Juniperus occidentalis var. occidentalis Hook.) encroachment has been previously documented in the sagebrush steppe and upper elevation aspen communities. While these vegetation changes and dynamics have been extensively studied, the ability to accurately predict future effects on vegetation structure in response to climatic effects requires the identification of climatic factors that most directly regulate growth across variations in spatial features, particularly when future climate change is likely. I sought to address this problem at the pine-woodland ecotone using tree-ring data for western juniper and ponderosa pine (Pinus ponderosa Dougl. Ex Loud.) from the Fremont National Forest of central Oregon. Site and soil-derived growth chronologies for the period 1950 to 2000 were developed for both species using standard dendrochronological techniques at 17 sites within the Fremont National Forest stratified by elevation (1584 and 1865 meters). Analysis of the climatic relationship with site and soil-derived chronologies using correlation and linear regression revealed that, similar to previous studies in Oregon, radial growth in both species is highly dependent on winter-spring precipitation events that recharge growing-season soil water. Ordinations of site- and soil-derived chronology principal components (PCA) scores for both species identified distinct gradients in growth patterns related to elevation, slope, and soil infiltration class. Low elevation sites had reduced growth in the nine driest years during 1950-2000 compared to high elevation sites. Slope was also positively associated with the ratio of standardized growth in wet years to dry years (W:D), a measure of climate sensitivity. Tree growth of both species on coarse-textured soils with rapid infiltration rates was more climate-sensitive (higher values of W:D) and was also reduced during drought years when compared to other infiltration classes. These findings suggest potentially significant variation in growth responses to future climate changes across distinct local features at the pine-woodland ecotone. Juniper and pine radial growth at sites that feature poor water-holding capacities (i.e., low elevation, steep slopes, and coarse-textured soils) can be expected to be most sensitive to future drought and climate fluctuations in southern Oregon. Close

• 8. [Article] Watershed response to western juniper control

  Western juniper (Juniperus occidentalis) encroachment has been associated with increased soil loss and reduced infiltration resulting in the loss of native herbaceous plant communities and the bird and ...

  Citation × Citation Citation Abstract Copy Title: Watershed response to western juniper control Author: Deboodt, Timothy L. Western juniper (Juniperus occidentalis) encroachment has been associated with increased soil loss and reduced infiltration resulting in the loss of native herbaceous plant communities and the bird and animal species that rely on them. Hydrologically, however, change in water yield has been linked with the amount of annual precipitation a site received. Studies published in the 1970’s and 1980’s, suggest that a minimum 4500 mm (18 inches) of annual precipitation was necessary before an increase in water yield manifested itself following vegetation manipulation. In 1993, a paired watershed study was initiated in the Camp Creek drainage, a tributary of the Crooked River of central Oregon, to evaluate the impacts of cutting western juniper on the hydrologic function of those sites. The study involved a paired watershed approach using watersheds of approximately 110 hectares (270 acres) each to evaluate changes in a system’s water budget following the reduction of western juniper. The 30 year average annual precipitation for the area is 3500 mm (13.75) and during the study period, annual precipitation ranged from 80 percent to 129 percent of average. In 2005, following 12 years of pretreatment monitoring in the 2 watersheds (Mays and Jensen) all post-European aged juniper (juniper < 140 years of age) were cut from the treatment watershed (Mays). Analysis indicated that juniper reduction significantly increased late season spring flow by 225 percent (alpha > .05), increased days of recorded ground water by an average of 41 days (alpha > .05) and increased the relative availability of late season soil moisture at soil depths of .76 m (27 inches) (alpha > 0.1). Ephemeral channel flow did not show a predictable trend during 2 years of post treatment measurements. Channel flow is dependent on spring snow melt and severe summer thunderstorm activity. When winter soils were greater than 0 degrees Celsius (32 degrees F), the source of channel flow in Mays was observed to be seepage from the channel banks. Channel flow in Jensen appeared to be a result of rock forcing subsurface flows to the surface. Vegetative responses showed significant increases in perennial forb canopy cover (alpha > .01) and annual forb and annual grass basal cover (alpha > .05). Increases were also found in reduction of percent bare ground and increase in shrub cover, but were not significant. A statistically insignificant decrease in perennial grass cover was noted in the treated watershed however a large amount of reproductive culms were noted in the treated watershed in 2007 compared to the control watershed. Hillslope erosion and channel morphology showed no predictable trend following treatment. Inherent differences in channel morphology between the two watershed prior to treatment existed. This difference may be a product of the two channels being at different evolutionary or successional stages relative to each other and thus indicating that channel recovery would be different for each watershed. The Camp Creek project illustrated that for this system, managing vegetation for water yield may be obtainable at a much lower precipitation threshold than what was previously reported in the literature. Title: Watershed response to western juniper control Author: Deboodt, Timothy L. Western juniper (Juniperus occidentalis) encroachment has been associated with increased soil loss and reduced infiltration resulting in the loss of native herbaceous plant communities and the bird and animal species that rely on them. Hydrologically, however, change in water yield has been linked with the amount of annual precipitation a site received. Studies published in the 1970’s and 1980’s, suggest that a minimum 4500 mm (18 inches) of annual precipitation was necessary before an increase in water yield manifested itself following vegetation manipulation. In 1993, a paired watershed study was initiated in the Camp Creek drainage, a tributary of the Crooked River of central Oregon, to evaluate the impacts of cutting western juniper on the hydrologic function of those sites. The study involved a paired watershed approach using watersheds of approximately 110 hectares (270 acres) each to evaluate changes in a system’s water budget following the reduction of western juniper. The 30 year average annual precipitation for the area is 3500 mm (13.75) and during the study period, annual precipitation ranged from 80 percent to 129 percent of average. In 2005, following 12 years of pretreatment monitoring in the 2 watersheds (Mays and Jensen) all post-European aged juniper (juniper < 140 years of age) were cut from the treatment watershed (Mays). Analysis indicated that juniper reduction significantly increased late season spring flow by 225 percent (alpha > .05), increased days of recorded ground water by an average of 41 days (alpha > .05) and increased the relative availability of late season soil moisture at soil depths of .76 m (27 inches) (alpha > 0.1). Ephemeral channel flow did not show a predictable trend during 2 years of post treatment measurements. Channel flow is dependent on spring snow melt and severe summer thunderstorm activity. When winter soils were greater than 0 degrees Celsius (32 degrees F), the source of channel flow in Mays was observed to be seepage from the channel banks. Channel flow in Jensen appeared to be a result of rock forcing subsurface flows to the surface. Vegetative responses showed significant increases in perennial forb canopy cover (alpha > .01) and annual forb and annual grass basal cover (alpha > .05). Increases were also found in reduction of percent bare ground and increase in shrub cover, but were not significant. A statistically insignificant decrease in perennial grass cover was noted in the treated watershed however a large amount of reproductive culms were noted in the treated watershed in 2007 compared to the control watershed. Hillslope erosion and channel morphology showed no predictable trend following treatment. Inherent differences in channel morphology between the two watershed prior to treatment existed. This difference may be a product of the two channels being at different evolutionary or successional stages relative to each other and thus indicating that channel recovery would be different for each watershed. The Camp Creek project illustrated that for this system, managing vegetation for water yield may be obtainable at a much lower precipitation threshold than what was previously reported in the literature. Close