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• 31. [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

• 32. [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

• 33. [Article] Persistence of western juniper resource islands following canopy removal

  Western juniper (Juniperus occidentalis) cover has more than doubled within the last century and currently occupies over 9 million acres in the Intermountain West. Encroachment has altered the spatial ...

  Citation × Citation Citation Abstract Copy Title: Persistence of western juniper resource islands following canopy removal Author: Miwa, Christopher Western juniper (Juniperus occidentalis) cover has more than doubled within the last century and currently occupies over 9 million acres in the Intermountain West. Encroachment has altered the spatial distribution of soil nutrients and plants in these systems, forming nutrient enriched 'resource islands,' under tree canopies. The purpose of this study was to determine the persistence of resource island characteristics after restoration treatment (tree removal). The study site was a BLM grazing allotment in Eastern Oregon where trees had been cut 1, 8 and 15 years ago. In each age class and in uncut western juniper woodlands juniper stumps or trees were randomly selected for sampling. At each bole three radial transects, set at 120º from each other, were marked and soil cores were collected to 5-cm depth at distances of 50, 100, 150 and 300-cm from the bole then combined to a single composite sample per distance class. Samples were analyzed for total C and N, soluble P, K, Ca, Fe, Si, Al and Na, inorganic NH₄ and NO₃, pH and gravimetric water content. Fifteen years after canopy removal there was still strong evidence of western juniper resource islands. Canopy soils were generally significantly higher in Ctot, Ntot, NO₃‾, P, K and Ca compared to intercanopy soils in all treatments; however, accumulations for several elements appeared to degrade with time since canopy removal, and at different rates. We attribute resource island persistence to deep litter mats beneath relic canopies. Due to the strong zonal distribution of understory vegetation in juniper duff and bare zones these nutrient enriched areas will continue to influence long-term successional pathways and should be taken into account for restoration purposes, such as seeding of forbs and grasses. Title: Persistence of western juniper resource islands following canopy removal Author: Miwa, Christopher Western juniper (Juniperus occidentalis) cover has more than doubled within the last century and currently occupies over 9 million acres in the Intermountain West. Encroachment has altered the spatial distribution of soil nutrients and plants in these systems, forming nutrient enriched 'resource islands,' under tree canopies. The purpose of this study was to determine the persistence of resource island characteristics after restoration treatment (tree removal). The study site was a BLM grazing allotment in Eastern Oregon where trees had been cut 1, 8 and 15 years ago. In each age class and in uncut western juniper woodlands juniper stumps or trees were randomly selected for sampling. At each bole three radial transects, set at 120º from each other, were marked and soil cores were collected to 5-cm depth at distances of 50, 100, 150 and 300-cm from the bole then combined to a single composite sample per distance class. Samples were analyzed for total C and N, soluble P, K, Ca, Fe, Si, Al and Na, inorganic NH₄ and NO₃, pH and gravimetric water content. Fifteen years after canopy removal there was still strong evidence of western juniper resource islands. Canopy soils were generally significantly higher in Ctot, Ntot, NO₃‾, P, K and Ca compared to intercanopy soils in all treatments; however, accumulations for several elements appeared to degrade with time since canopy removal, and at different rates. We attribute resource island persistence to deep litter mats beneath relic canopies. Due to the strong zonal distribution of understory vegetation in juniper duff and bare zones these nutrient enriched areas will continue to influence long-term successional pathways and should be taken into account for restoration purposes, such as seeding of forbs and grasses. Close

• 34. [Article] Vegetation Response to Western Juniper Slash Treatments

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Springer ...

  Citation × Citation Citation Abstract Copy Title: Vegetation Response to Western Juniper Slash Treatments Author: O’Connor, Casey, Bates, Jonathan D., Miller, Rick To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://www.springer.com/?SGWID=0-102-0-0-0. Title: Vegetation Response to Western Juniper Slash Treatments Author: O’Connor, Casey, Bates, Jonathan D., Miller, Rick To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://www.springer.com/?SGWID=0-102-0-0-0. Close

• 35. [Article] Effect of western juniper on understory herbage production in Central Oregon

  Evidence suggests that western juniper (Juniperus occidentalis) in Central Oregon affects understory production and composition. As trees increase in size and density, understory production is reduced ...

  Citation × Citation Citation Abstract Copy Title: Effect of western juniper on understory herbage production in Central Oregon Author: Vaitkus, Milda R. Evidence suggests that western juniper (Juniperus occidentalis) in Central Oregon affects understory production and composition. As trees increase in size and density, understory production is reduced and composition changes. This study was designed to identify the relationship between production and composition of understory vegetation and various tree canopy sizes of western juniper, and to describe the responses of understory vegetation to removal of western juniper. Understory production was sampled in 1983 and 1984 by clipping plots on an individual trees basis from areas with trees present and areas from which trees had been removed in 1982. Biomass production was determined from trees within three canopy diameter size classes and from two zones, beneath the canopy and in the interspace. Production was examined on two sites, a lower slope, shallow soil site and an upper slope, moderately deep soil site. Some year-to-year differences in production of individual species and specific tree sizes may be explained by variation in precipitation during critical growth periods the two years of the study. Sandberg bluegrass and, possibly, Idaho fescue production may have been greater in 1983 than 1984 due to variation in late spring precipitation, especially on shallow soils associated with small trees. Differences in patterns of production of individual species were most clearly developed associated with large, rather than small and intermediate trees. Cheatgrass, squirreltail, bluebunch wheatgrass, and Idaho fescue were common beneath the canopy, while Sandberg bluegrass was common in the interspaces. Cheatgrass and perennial forb production beneath the canopy increased with tree size. Production of other species, such as Sandberg bluegrass, was apparently not affected by tree size. Canopy removal resulted in species-specific increases in biomass production both years. Production increases were greater beneath the canopy than in the interspaces. Perennial grasses provided small variable production increases beneath the canopy of large trees. Annual grasses, primarily cheatgrass, and annual forbs, primarily Epilobium paniculatum, contributed most to elevated productivity the first two years following juniper removal. Cheatgrass response was mainly associated with large trees, while annual forb response was independent of tree size. Sandberg bluegrass production seemed more closely tied to growing season precipitation than to canopy removal, regardless of tree size. Title: Effect of western juniper on understory herbage production in Central Oregon Author: Vaitkus, Milda R. Evidence suggests that western juniper (Juniperus occidentalis) in Central Oregon affects understory production and composition. As trees increase in size and density, understory production is reduced and composition changes. This study was designed to identify the relationship between production and composition of understory vegetation and various tree canopy sizes of western juniper, and to describe the responses of understory vegetation to removal of western juniper. Understory production was sampled in 1983 and 1984 by clipping plots on an individual trees basis from areas with trees present and areas from which trees had been removed in 1982. Biomass production was determined from trees within three canopy diameter size classes and from two zones, beneath the canopy and in the interspace. Production was examined on two sites, a lower slope, shallow soil site and an upper slope, moderately deep soil site. Some year-to-year differences in production of individual species and specific tree sizes may be explained by variation in precipitation during critical growth periods the two years of the study. Sandberg bluegrass and, possibly, Idaho fescue production may have been greater in 1983 than 1984 due to variation in late spring precipitation, especially on shallow soils associated with small trees. Differences in patterns of production of individual species were most clearly developed associated with large, rather than small and intermediate trees. Cheatgrass, squirreltail, bluebunch wheatgrass, and Idaho fescue were common beneath the canopy, while Sandberg bluegrass was common in the interspaces. Cheatgrass and perennial forb production beneath the canopy increased with tree size. Production of other species, such as Sandberg bluegrass, was apparently not affected by tree size. Canopy removal resulted in species-specific increases in biomass production both years. Production increases were greater beneath the canopy than in the interspaces. Perennial grasses provided small variable production increases beneath the canopy of large trees. Annual grasses, primarily cheatgrass, and annual forbs, primarily Epilobium paniculatum, contributed most to elevated productivity the first two years following juniper removal. Cheatgrass response was mainly associated with large trees, while annual forb response was independent of tree size. Sandberg bluegrass production seemed more closely tied to growing season precipitation than to canopy removal, regardless of tree size. Close

• 36. [Article] Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon

  For a previous discussion paper please see: http://hdl.handle.net/1957/58002

  Citation × Citation Citation Abstract Copy Title: Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon Author: Law, B. E., Berner, L. T. For a previous discussion paper please see: http://hdl.handle.net/1957/58002 Title: Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon Author: Law, B. E., Berner, L. T. For a previous discussion paper please see: http://hdl.handle.net/1957/58002 Close

• 37. [Article] Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon

  The final revised paper is available at: http://hdl.handle.net/1957/58001

  Citation × Citation Citation Abstract Copy Title: Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon Author: Law, B. E., Berner, L. T. The final revised paper is available at: http://hdl.handle.net/1957/58001 Title: Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon Author: Law, B. E., Berner, L. T. The final revised paper is available at: http://hdl.handle.net/1957/58001 Close

• 38. [Article] Man and the land : an ecological history of fire and grazing on eastern Oregon rangelands

  Ecological and historical information are combined in examining the environmental influence of fire and grazing on rangelands in eastern Oregon through time. Competitive relationships between herbaceous ...

  Citation × Citation Citation Abstract Copy Title: Man and the land : an ecological history of fire and grazing on eastern Oregon rangelands Author: Shinn, Dean Allison Ecological and historical information are combined in examining the environmental influence of fire and grazing on rangelands in eastern Oregon through time. Competitive relationships between herbaceous and woody flora in the northern Great Basin are discussed, focusing broadly on the shrubsteppe regions 'of Franklin and Dyrness (1973) but with special reference to the Artemisia/Agropyron association. Impacts of native and domestic grazing animals and of cultural burning are traced from the distant past into recent history. During the Pleistocene Epoch North America supported a wide diversity of large mammals. Toward the end of the Pleistocene, many of these fauna became extinct, perhaps as a result of post-glacial climatic change, perhaps also under the influence of incoming primitive hunting cultures and their broadcast burning practices. Some question exists about the intensity of native grazing in the northern Great Basin during the last few thousand years. Actual levels of bison populations and the duration of their residence in the study area have not been determined. The character of indigenous vegetations, however, indicates that native grazing was relatively light for an extended period primevally. Twenty-four references to native cultural burning at the time of European contact were found in historical journals. Though the antiquity of these customs is uncertain, an analysis of Native American fire myths demonstrates the depth of native cultural perceptions of the relationship between man and fire, and supports the likelihood that fire was used primevally in the northern Great Basin as it was used by aboriginal peoples elsewhere in North America. With the influx of European culture during the 19th century, misapprehensions about fire among whites distorted the influence of native cultural burning. Exotic flora and fauna were introduced, and ecosystems began to change. Large herds of livestock depleted native herbaceous populations. Early irresponsible burning by whites became associated with declining rangeland resources, and efforts toward total fire suppression became incorporated in developing conservation policies. Native woody flora and exotics began to invade open rangeland communities. Climatic flux during the period of European settlement in the northern Great Basin may have exacerbated the impacts of intensified grazing and elimination of burning. Early photographs of rangelands in east-central Oregon were gathered; their dates range from 1880 to the early 1930's. Sites represented in these pictures were re-photographed in 1976. Photo-set comparisons show expansion of western juniper (Juniperus occidentalis) populations into rangeland ecosystems, demonstrating the consequences of cultural disturbances during the last 150 to 200 years. Title: Man and the land : an ecological history of fire and grazing on eastern Oregon rangelands Author: Shinn, Dean Allison Ecological and historical information are combined in examining the environmental influence of fire and grazing on rangelands in eastern Oregon through time. Competitive relationships between herbaceous and woody flora in the northern Great Basin are discussed, focusing broadly on the shrubsteppe regions 'of Franklin and Dyrness (1973) but with special reference to the Artemisia/Agropyron association. Impacts of native and domestic grazing animals and of cultural burning are traced from the distant past into recent history. During the Pleistocene Epoch North America supported a wide diversity of large mammals. Toward the end of the Pleistocene, many of these fauna became extinct, perhaps as a result of post-glacial climatic change, perhaps also under the influence of incoming primitive hunting cultures and their broadcast burning practices. Some question exists about the intensity of native grazing in the northern Great Basin during the last few thousand years. Actual levels of bison populations and the duration of their residence in the study area have not been determined. The character of indigenous vegetations, however, indicates that native grazing was relatively light for an extended period primevally. Twenty-four references to native cultural burning at the time of European contact were found in historical journals. Though the antiquity of these customs is uncertain, an analysis of Native American fire myths demonstrates the depth of native cultural perceptions of the relationship between man and fire, and supports the likelihood that fire was used primevally in the northern Great Basin as it was used by aboriginal peoples elsewhere in North America. With the influx of European culture during the 19th century, misapprehensions about fire among whites distorted the influence of native cultural burning. Exotic flora and fauna were introduced, and ecosystems began to change. Large herds of livestock depleted native herbaceous populations. Early irresponsible burning by whites became associated with declining rangeland resources, and efforts toward total fire suppression became incorporated in developing conservation policies. Native woody flora and exotics began to invade open rangeland communities. Climatic flux during the period of European settlement in the northern Great Basin may have exacerbated the impacts of intensified grazing and elimination of burning. Early photographs of rangelands in east-central Oregon were gathered; their dates range from 1880 to the early 1930's. Sites represented in these pictures were re-photographed in 1976. Photo-set comparisons show expansion of western juniper (Juniperus occidentalis) populations into rangeland ecosystems, demonstrating the consequences of cultural disturbances during the last 150 to 200 years. Close

• 39. [Article] Vegetation and soil response to tree removal methods in invasive western juniper woodlands

  On piñon-juniper encroached sites that lack the understory fuels to carry a prescribed fire, treatment options are limited to mechanical methods. Cutting with chainsaws and leaving the trees on site has ...

  Citation × Citation Citation Abstract Copy Title: Vegetation and soil response to tree removal methods in invasive western juniper woodlands Author: O'Connor, Casey A. On piñon-juniper encroached sites that lack the understory fuels to carry a prescribed fire, treatment options are limited to mechanical methods. Cutting with chainsaws and leaving the trees on site has been the primary treatment method for such sites, however this method creates a potential fire hazard, particularly in the first 2-3 years when needles remain suspended on downed trees. Follow-up treatments to remove juniper fuels, such as broadcast burning downed trees or moving slash into piles with machinery followed by burning are becoming more common practices on private and public lands. There is limited information on the impacts of mechanical and fire treatments on herbaceous recovery and impacts to soil nutrients and characteristics. It is important to evaluate these treatments to provide resource managers with ecological information to assist in developing appropriate fuel reduction measures. This study sampled herbaceous vegetation and soil attributes of three common mechanical treatments used to treat invasive western juniper (Juniperus occidentalis var. occidentalis Vasek) woodlands: Cut & Leave, Cut & Burn, and Pile & Burn. Sampling consisted of cover and density of herbaceous species and life forms (groups of species that function similarly), as well as total ground cover, and soil attributes including: carbon (C), nitrogen (N), carbon:nitrogen ratio (C:N), phosphorus (P), potassium (K), sulfate-sulfur (SO4-), calcium(Ca), magnesium (Mg), organic matter (OM~loss on ignition), cation exchange capacity (CEC), and power of hydrogen (pH). A randomized complete block experimental design (RCBD) was used with five 1-hectare blocks and three treatment plots per block (with piling plots being ½ hectare in size, and the other two treatment plots each ¼ hectare in size). Within each treatment plot, herbaceous vegetation sampling was stratified between three microsites: the slash microsite (beneath the three slash treatments; cut trees, burned trees, and burned piles), in the litter deposition microsite (litter zone around the stump) and the interspace microsite (between trees). Soil attributes were only sampled in the slash and interspace microsites, at two depths (0-4cm and 0-25cm). Each microsite within each plot was sampled by 40, 0.2m2 herbaceous frames and three composited soil samples from each depth. Mechanical treatments were completed in the fall of 2005 and prescribed fire treatments were completed in the fall of 2006. Treatment analysis compared pre and post treatment herbaceous data from 2005 and 2007, and soil attribute data from 2006 and 2007. Bare ground increased and litter and cover and density of most herbaceous species/life form groups declined beneath Cut & Burn and Pile & Burn treatments compared to the Cut & Leave treatment. The largest declines in cover and density of herbaceous species/life forms were recorded beneath burned piles. The largest changes measured adjacent to slash treatment locations (in the litter deposition and interspace microsites) were in the Cut & Burn plots due to fire spreading out burned trees. In the litter deposition microsite of the Cut & Burn treatment in 2007 total herbaceous cover was 1/3 and 1/2 that measured in the Cut & Leave and Pile & Burn plots, respectively. Contrarily the interspace microsite of the Cut & Burn treatment in 2007 indicated a slight (although insignificant) increase in herbaceous cover, with annual forb cover twice that measured in either of the other treatments. Concentrations of C, N, OM, and CEC were largely unchanged from pre-treatment levels in the compared treatments, however SO4, Mg, Ca, K, and pH all increased in response to burning compared to the Cut & Leave treatment. Implications of this research are limited to the first year post burn-treatment. However, these findings can be used as a general guide to choosing slash treatments to meet specific objectives. Determination of which of these treatments to use is largely dependent upon management objectives and site conditions. The high degree of vegetation disturbance and nutrient release measured beneath the Pile & Burn slash treatment could pose potential problems with invasive species establishment. However, the Cut & Burn treatment had similar, although less dramatic, vegetation disturbances and nutrient releases beneath burned slash, which covered a larger proportion of area than the Pile & Burn treatment. If a similar degree of invasive species establishment occurs in both of these slash burning treatments, the Pile & Burn treatment may be a better option due to the smaller area impacted. Measurements indicated little impact to vegetation in the Cut & Leave treatment, however wildfire risk could diminish the short term benefits of this treatment. Long term monitoring of herbaceous vegetation and soil attribute response among these three slash treatments is needed to make solid inferences of the site recovery following treatments to assist in land management decisions. Title: Vegetation and soil response to tree removal methods in invasive western juniper woodlands Author: O'Connor, Casey A. On piñon-juniper encroached sites that lack the understory fuels to carry a prescribed fire, treatment options are limited to mechanical methods. Cutting with chainsaws and leaving the trees on site has been the primary treatment method for such sites, however this method creates a potential fire hazard, particularly in the first 2-3 years when needles remain suspended on downed trees. Follow-up treatments to remove juniper fuels, such as broadcast burning downed trees or moving slash into piles with machinery followed by burning are becoming more common practices on private and public lands. There is limited information on the impacts of mechanical and fire treatments on herbaceous recovery and impacts to soil nutrients and characteristics. It is important to evaluate these treatments to provide resource managers with ecological information to assist in developing appropriate fuel reduction measures. This study sampled herbaceous vegetation and soil attributes of three common mechanical treatments used to treat invasive western juniper (Juniperus occidentalis var. occidentalis Vasek) woodlands: Cut & Leave, Cut & Burn, and Pile & Burn. Sampling consisted of cover and density of herbaceous species and life forms (groups of species that function similarly), as well as total ground cover, and soil attributes including: carbon (C), nitrogen (N), carbon:nitrogen ratio (C:N), phosphorus (P), potassium (K), sulfate-sulfur (SO4-), calcium(Ca), magnesium (Mg), organic matter (OM~loss on ignition), cation exchange capacity (CEC), and power of hydrogen (pH). A randomized complete block experimental design (RCBD) was used with five 1-hectare blocks and three treatment plots per block (with piling plots being ½ hectare in size, and the other two treatment plots each ¼ hectare in size). Within each treatment plot, herbaceous vegetation sampling was stratified between three microsites: the slash microsite (beneath the three slash treatments; cut trees, burned trees, and burned piles), in the litter deposition microsite (litter zone around the stump) and the interspace microsite (between trees). Soil attributes were only sampled in the slash and interspace microsites, at two depths (0-4cm and 0-25cm). Each microsite within each plot was sampled by 40, 0.2m2 herbaceous frames and three composited soil samples from each depth. Mechanical treatments were completed in the fall of 2005 and prescribed fire treatments were completed in the fall of 2006. Treatment analysis compared pre and post treatment herbaceous data from 2005 and 2007, and soil attribute data from 2006 and 2007. Bare ground increased and litter and cover and density of most herbaceous species/life form groups declined beneath Cut & Burn and Pile & Burn treatments compared to the Cut & Leave treatment. The largest declines in cover and density of herbaceous species/life forms were recorded beneath burned piles. The largest changes measured adjacent to slash treatment locations (in the litter deposition and interspace microsites) were in the Cut & Burn plots due to fire spreading out burned trees. In the litter deposition microsite of the Cut & Burn treatment in 2007 total herbaceous cover was 1/3 and 1/2 that measured in the Cut & Leave and Pile & Burn plots, respectively. Contrarily the interspace microsite of the Cut & Burn treatment in 2007 indicated a slight (although insignificant) increase in herbaceous cover, with annual forb cover twice that measured in either of the other treatments. Concentrations of C, N, OM, and CEC were largely unchanged from pre-treatment levels in the compared treatments, however SO4, Mg, Ca, K, and pH all increased in response to burning compared to the Cut & Leave treatment. Implications of this research are limited to the first year post burn-treatment. However, these findings can be used as a general guide to choosing slash treatments to meet specific objectives. Determination of which of these treatments to use is largely dependent upon management objectives and site conditions. The high degree of vegetation disturbance and nutrient release measured beneath the Pile & Burn slash treatment could pose potential problems with invasive species establishment. However, the Cut & Burn treatment had similar, although less dramatic, vegetation disturbances and nutrient releases beneath burned slash, which covered a larger proportion of area than the Pile & Burn treatment. If a similar degree of invasive species establishment occurs in both of these slash burning treatments, the Pile & Burn treatment may be a better option due to the smaller area impacted. Measurements indicated little impact to vegetation in the Cut & Leave treatment, however wildfire risk could diminish the short term benefits of this treatment. Long term monitoring of herbaceous vegetation and soil attribute response among these three slash treatments is needed to make solid inferences of the site recovery following treatments to assist in land management decisions. Close

• 40. [Image] A review of scientific information on issues related to the use and management of water resources in the Pacific Northwest

  	Abstract Everest, Fred H.; Stouder, Deanna J.; Kakoyannis, Christina; Houston, Laurie; Stankey, George; Kline, Jeffery; Alig, Ralph. 2004. A review of scientific information ...
  	Citation × Citation Citation Abstract Copy Title: A review of scientific information on issues related to the use and management of water resources in the Pacific Northwest Year: 2004 Abstract Everest, Fred H.; Stouder, Deanna J.; Kakoyannis, Christina; Houston, Laurie; Stankey, George; Kline, Jeffery; Alig, Ralph. 2004. A review of scientific information on issues related to the use and management of water resources in the Pacific Northwest. Gen. Tech. Rep. PNW-GTR-595. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 128 p. Fresh water is a valuable and essential commodity in the Pacific Northwest States, specifically Oregon, Washington, and Idaho, and one provided abundantly by forested watersheds in the region. The maintenance and growth of industrial, municipal, agricultural, and recreational activities in the region are dependent on adequate and sustainable supplies of fresh water from surface and ground-water sources. Future development, especially in the semiarid intermountain area, depends on the conservation and expansion of the region's water resource. This synthesis reviews the state of our knowledge and condition of water resources in the Pacific Northwest. Keywords: Water distribution, flow regimes, water demand, conflicts, tools, water use. Title: A review of scientific information on issues related to the use and management of water resources in the Pacific Northwest Year: 2004 Abstract Everest, Fred H.; Stouder, Deanna J.; Kakoyannis, Christina; Houston, Laurie; Stankey, George; Kline, Jeffery; Alig, Ralph. 2004. A review of scientific information on issues related to the use and management of water resources in the Pacific Northwest. Gen. Tech. Rep. PNW-GTR-595. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 128 p. Fresh water is a valuable and essential commodity in the Pacific Northwest States, specifically Oregon, Washington, and Idaho, and one provided abundantly by forested watersheds in the region. The maintenance and growth of industrial, municipal, agricultural, and recreational activities in the region are dependent on adequate and sustainable supplies of fresh water from surface and ground-water sources. Future development, especially in the semiarid intermountain area, depends on the conservation and expansion of the region's water resource. This synthesis reviews the state of our knowledge and condition of water resources in the Pacific Northwest. Keywords: Water distribution, flow regimes, water demand, conflicts, tools, water use. Close