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• 11. [Article] Donner und Blitzen Sub-basin Watershed Assessment

  Abstract -- The 2003 Donner und Blitzen Sub-basin Watershed Assessment was prepared by the Harney County Watershed Council. The Donner und Blitzen Sub-Basin is 505,127 acres located in Harney County, Oregon. ...

  Citation × Citation Citation Abstract Copy Title: Donner und Blitzen Sub-basin Watershed Assessment Abstract -- The 2003 Donner und Blitzen Sub-basin Watershed Assessment was prepared by the Harney County Watershed Council. The Donner und Blitzen Sub-Basin is 505,127 acres located in Harney County, Oregon. The Donner und Blitzen Sub-basin has 1,391 miles of streams within its 174 mile perimeter. The document discusses history of the sub-basin and the historical land uses. Following history and description, the results of the assessments are discussed and related to the land and resource use of the sub-basin and the current watershed issues based on those uses. The end of the document discussed the proposed changes to the sub-basin based on assessment results in relation to current and past land resouce use and the goals of the Harney County Watershed Council. Title: Donner und Blitzen Sub-basin Watershed Assessment Abstract -- The 2003 Donner und Blitzen Sub-basin Watershed Assessment was prepared by the Harney County Watershed Council. The Donner und Blitzen Sub-Basin is 505,127 acres located in Harney County, Oregon. The Donner und Blitzen Sub-basin has 1,391 miles of streams within its 174 mile perimeter. The document discusses history of the sub-basin and the historical land uses. Following history and description, the results of the assessments are discussed and related to the land and resource use of the sub-basin and the current watershed issues based on those uses. The end of the document discussed the proposed changes to the sub-basin based on assessment results in relation to current and past land resouce use and the goals of the Harney County Watershed Council. Close

• 12. [Article] Historic Douglas-Fir Colonization and Land Use Practices at Restoration Sites Near Eugene, OR

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

  Citation × Citation Citation Abstract Copy Title: Historic Douglas-Fir Colonization and Land Use Practices at Restoration Sites Near Eugene, OR Author: Martin, Wade Year: 2015 49 pages. A thesis presented to the Department of Environment Science and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2015. Title: Historic Douglas-Fir Colonization and Land Use Practices at Restoration Sites Near Eugene, OR Author: Martin, Wade Year: 2015 49 pages. A thesis presented to the Department of Environment Science and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2015. Close

• 13. [Article] Historical Vegetation of Three Salmon-Bearing Watersheds in the Interior Columbia River Basin

  Land use practices can be a contributing factor to environmental degradation and have been the focus of many ecological studies. One aspect that is less addressed is land use history and the effects that ...

  Citation × Citation Citation Abstract Copy Title: Historical Vegetation of Three Salmon-Bearing Watersheds in the Interior Columbia River Basin Author: Smith, Tyanna Year: 2014 Land use practices can be a contributing factor to environmental degradation and have been the focus of many ecological studies. One aspect that is less addressed is land use history and the effects that past practices, such as logging and grazing, can have on the current landscape. This paper describes research and the synthesis of material on the environmental history and watershed characteristics for three watersheds located within spawning and rearing areas for Chinook salmon in the Grande Ronde River Basin in Northeast Oregon: upper Grande Ronde River, Catherine Creek, and Minam River. The Grande Ronde Basin is critical spawning and rearing habitat for salmonids listed under the Endangered Species Act. The primary historical data sources for reconstructing 19th century stream and riparian conditions are the General Land Office township survey notes from 1863 - 1901. Data about the habitat conditions of the landscape were extracted from notes of each township survey source regarding vegetation, stream crossings, and other features found on the landscape in tabular and spatial forms. Data were organized to describe common stream and riparian conditions for the historical time period using a geographic information system. Watershed basin, Chinook salmon life history, ecoregion and surveyor were analyzed using multivariate techniques to determine which parameters were strongly connected to historical vegetation. Ecoregion had the strongest correlation with plant communities. For future research, these historical data could be compared to current habitat survey data, such as the Oregon Department of Fish & Wildlife’s Aquatic Habitat Inventories, to evaluate the degree of change over time of stream and riparian conditions. Title: Historical Vegetation of Three Salmon-Bearing Watersheds in the Interior Columbia River Basin Author: Smith, Tyanna Year: 2014 Land use practices can be a contributing factor to environmental degradation and have been the focus of many ecological studies. One aspect that is less addressed is land use history and the effects that past practices, such as logging and grazing, can have on the current landscape. This paper describes research and the synthesis of material on the environmental history and watershed characteristics for three watersheds located within spawning and rearing areas for Chinook salmon in the Grande Ronde River Basin in Northeast Oregon: upper Grande Ronde River, Catherine Creek, and Minam River. The Grande Ronde Basin is critical spawning and rearing habitat for salmonids listed under the Endangered Species Act. The primary historical data sources for reconstructing 19th century stream and riparian conditions are the General Land Office township survey notes from 1863 - 1901. Data about the habitat conditions of the landscape were extracted from notes of each township survey source regarding vegetation, stream crossings, and other features found on the landscape in tabular and spatial forms. Data were organized to describe common stream and riparian conditions for the historical time period using a geographic information system. Watershed basin, Chinook salmon life history, ecoregion and surveyor were analyzed using multivariate techniques to determine which parameters were strongly connected to historical vegetation. Ecoregion had the strongest correlation with plant communities. For future research, these historical data could be compared to current habitat survey data, such as the Oregon Department of Fish & Wildlife’s Aquatic Habitat Inventories, to evaluate the degree of change over time of stream and riparian conditions. Close

• 14. [Article] Portland : Civic planning, development, & public works, 1851-1965

  68 pp. Bookmarks supplied by UO. Maps, figures, bibliography. Published March, 2009. Captured March 26, 2009.

  Citation × Citation Citation Abstract Copy Title: Portland : Civic planning, development, & public works, 1851-1965 Author: Portland (Or.). Bureau of Planning and Sustainability, Portland (Or.) Year: 2009 68 pp. Bookmarks supplied by UO. Maps, figures, bibliography. Published March, 2009. Captured March 26, 2009. Title: Portland : Civic planning, development, & public works, 1851-1965 Author: Portland (Or.). Bureau of Planning and Sustainability, Portland (Or.) Year: 2009 68 pp. Bookmarks supplied by UO. Maps, figures, bibliography. Published March, 2009. Captured March 26, 2009. Close

• 15. [Article] Oregon Explorer : Natural resources information for current and future decision-makers

  Oregon Explorer (www.oregonexplorer.info), a natural resources digital library developed by Oregon State University Libraries and the Institute for Natural Resources, was created for Oregon’s natural resource ...

  Citation × Citation Citation Abstract Copy Title: Oregon Explorer : Natural resources information for current and future decision-makers Author: Salwasser, Janine, Wirth, Andrea A. Oregon Explorer (www.oregonexplorer.info), a natural resources digital library developed by Oregon State University Libraries and the Institute for Natural Resources, was created for Oregon’s natural resource decision-makers to promote informed and streamlined public and private decision-making. Examples of projects and successes of the Oregon Explorer include a basin portal for the Umpqua River, developed in conjunction with the Partnership for Umpqua Rivers, as well as topic portals, such as the Land Use Explorer launched in October 2007 to inform Oregonians about land use history and current issues. We have learned that in the natural resources arena, user needs change with different geographies, yet the adaptations made at the local level are useful in expanding the content and services delivered at the statewide level. It is not enough to just provide access to data or documents. Users want access to a wide variety of integrated information resources—digital documents, interactive maps and reports, decision support, high resolution imagery, and access to available expertise. With Oregon Explorer becoming established as a tool for decision-makers and citizens, members of the team are exploring opportunities to use the digital library in classroom settings. Students in Oregon’s K-12 schools and OSU’s undergraduates are groups that we feel could benefit from the natural resources information and tools available. Proposals are being developed to extend Oregon Explorer’s capabilities for use in primary and secondary education. Oregon Explorer is being used in several university classrooms and will become more integrated as the content and tools grow and as strategies for further incorporation are developed. This evolving natural resources digital library will enable current and future decision-makers to learn about Oregon's environment and to actively engage in creating and sharing knowledge before decisions are made. Title: Oregon Explorer : Natural resources information for current and future decision-makers Author: Salwasser, Janine, Wirth, Andrea A. Oregon Explorer (www.oregonexplorer.info), a natural resources digital library developed by Oregon State University Libraries and the Institute for Natural Resources, was created for Oregon’s natural resource decision-makers to promote informed and streamlined public and private decision-making. Examples of projects and successes of the Oregon Explorer include a basin portal for the Umpqua River, developed in conjunction with the Partnership for Umpqua Rivers, as well as topic portals, such as the Land Use Explorer launched in October 2007 to inform Oregonians about land use history and current issues. We have learned that in the natural resources arena, user needs change with different geographies, yet the adaptations made at the local level are useful in expanding the content and services delivered at the statewide level. It is not enough to just provide access to data or documents. Users want access to a wide variety of integrated information resources—digital documents, interactive maps and reports, decision support, high resolution imagery, and access to available expertise. With Oregon Explorer becoming established as a tool for decision-makers and citizens, members of the team are exploring opportunities to use the digital library in classroom settings. Students in Oregon’s K-12 schools and OSU’s undergraduates are groups that we feel could benefit from the natural resources information and tools available. Proposals are being developed to extend Oregon Explorer’s capabilities for use in primary and secondary education. Oregon Explorer is being used in several university classrooms and will become more integrated as the content and tools grow and as strategies for further incorporation are developed. This evolving natural resources digital library will enable current and future decision-makers to learn about Oregon's environment and to actively engage in creating and sharing knowledge before decisions are made. Close

• 16. [Article] Tree Growth and Spatial Pattern in Two Forest Park Permanent Plots: A Look at Stand Composition and Condition

  In June of 2010, two permanent research plots were established in Forest Park, based on their differing proximities to downtown Portland, Oregon. As part of a long-term ecological research project that ...

  Citation × Citation Citation Abstract Copy Title: Tree Growth and Spatial Pattern in Two Forest Park Permanent Plots: A Look at Stand Composition and Condition Author: McDonald, Hannah Beth Year: 2011 In June of 2010, two permanent research plots were established in Forest Park, based on their differing proximities to downtown Portland, Oregon. As part of a long-term ecological research project that seeks to explore the ecological status and human thumbprint on this 5,100 acre forested reserve, the 2010 tree data was investigated for emergent compositional and spatial patterns. Stand composition, tree size, growth rates, and spatial patterns were analyzed, along with ecological and land use histories. Results indicate that the Balch plot, more closely located to the urban center, has different stand composition, condition, and vegetation growth rates, compared to the more rural Miller site. This study supports findings from a study done by Broshot in 2009, where more urban plots demonstrate a different stand composition and recruitment pattern than rural sites. The study is an initial step for exploring questions regarding the ecological status of Forest Park and how land use and disturbance, past and present, shape Portland's forested reserve. Title: Tree Growth and Spatial Pattern in Two Forest Park Permanent Plots: A Look at Stand Composition and Condition Author: McDonald, Hannah Beth Year: 2011 In June of 2010, two permanent research plots were established in Forest Park, based on their differing proximities to downtown Portland, Oregon. As part of a long-term ecological research project that seeks to explore the ecological status and human thumbprint on this 5,100 acre forested reserve, the 2010 tree data was investigated for emergent compositional and spatial patterns. Stand composition, tree size, growth rates, and spatial patterns were analyzed, along with ecological and land use histories. Results indicate that the Balch plot, more closely located to the urban center, has different stand composition, condition, and vegetation growth rates, compared to the more rural Miller site. This study supports findings from a study done by Broshot in 2009, where more urban plots demonstrate a different stand composition and recruitment pattern than rural sites. The study is an initial step for exploring questions regarding the ecological status of Forest Park and how land use and disturbance, past and present, shape Portland's forested reserve. Close

• 17. [Article] Long-Term Integrated Studies Show Complex and Surprising Effects of Climate Change in the Northern Hardwood Forest

  Evaluations of the local effects of global change are often confounded by the interactions of natural and anthropogenic factors that overshadow the effects of climate changes on ecosystems. Long-term watershed ...

  Citation × Citation Citation Abstract Copy Title: Long-Term Integrated Studies Show Complex and Surprising Effects of Climate Change in the Northern Hardwood Forest Author: Groffman, Peter M., Rustad, Lindsay E., Templer, Pamela H., Campbell, John L., Christenson, Lynn M., Lany, Nina K., Socci, Anne M., Vadeboncoeur, Matthew A., Schaberg, Paul G., Wilson, Geoffrey W., Driscoll, Charles T., Fahey, Timothy J., Fisk, Melany C., Goodale, Christine L., Green, Mark B., Hamburg, Steven P., Johnson, Chris E., Mitchell, Mryon J., Morse, Jennifer L., Pardo, Linda H., Rodenhouse, Nicholas L. Year: 2012 Evaluations of the local effects of global change are often confounded by the interactions of natural and anthropogenic factors that overshadow the effects of climate changes on ecosystems. Long-term watershed and natural elevation gradient studies at the Hubbard Brook Experimental Forest and in the surrounding region show surprising results demonstrating the effects of climate change on hydrologic variables (e.g., evapotranspiration, streamflow, soil moisture); the importance of changes in phenology on water, carbon, and nitrogen fluxes during critical seasonal transition periods; winter climate change effects on plant and animal community composition and ecosystem services; and the effects of anthropogenic disturbances and land-use history on plant community composition. These studies highlight the value of long-term integrated research for assessments of the subtle effects of changing climate on complex ecosystems Title: Long-Term Integrated Studies Show Complex and Surprising Effects of Climate Change in the Northern Hardwood Forest Author: Groffman, Peter M., Rustad, Lindsay E., Templer, Pamela H., Campbell, John L., Christenson, Lynn M., Lany, Nina K., Socci, Anne M., Vadeboncoeur, Matthew A., Schaberg, Paul G., Wilson, Geoffrey W., Driscoll, Charles T., Fahey, Timothy J., Fisk, Melany C., Goodale, Christine L., Green, Mark B., Hamburg, Steven P., Johnson, Chris E., Mitchell, Mryon J., Morse, Jennifer L., Pardo, Linda H., Rodenhouse, Nicholas L. Year: 2012 Evaluations of the local effects of global change are often confounded by the interactions of natural and anthropogenic factors that overshadow the effects of climate changes on ecosystems. Long-term watershed and natural elevation gradient studies at the Hubbard Brook Experimental Forest and in the surrounding region show surprising results demonstrating the effects of climate change on hydrologic variables (e.g., evapotranspiration, streamflow, soil moisture); the importance of changes in phenology on water, carbon, and nitrogen fluxes during critical seasonal transition periods; winter climate change effects on plant and animal community composition and ecosystem services; and the effects of anthropogenic disturbances and land-use history on plant community composition. These studies highlight the value of long-term integrated research for assessments of the subtle effects of changing climate on complex ecosystems Close

• 18. [Article] Mesoscale Variation in Snag and Hardwood Densities and Sizes in Old-Growth Forests in Western Oregon

  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 Society ...

  Citation × Citation Citation Abstract Copy Title: Mesoscale Variation in Snag and Hardwood Densities and Sizes in Old-Growth Forests in Western Oregon Author: Bright, Cheryl, Puettmann, Klaus, Ares, Adrian 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 Society of American Foresters and can be found at: http://www.safnet.org/. Title: Mesoscale Variation in Snag and Hardwood Densities and Sizes in Old-Growth Forests in Western Oregon Author: Bright, Cheryl, Puettmann, Klaus, Ares, Adrian 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 Society of American Foresters and can be found at: http://www.safnet.org/. Close

• 19. [Article] Hydrologic and Land Cover Effects on Sources and Fate of In-Stream Fluorescent Dissolved Organic Matter

  Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM ...

  Citation × Citation Citation Abstract Copy Title: Hydrologic and Land Cover Effects on Sources and Fate of In-Stream Fluorescent Dissolved Organic Matter Author: Lee, Baek Soo P. Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM compositions in catchments of the western U.S. are poorly understood. UV and fluorescent spectroscopy is a simpler, faster, and less expensive DOM fingerprinting technique compared to techniques, such as nuclear magnetic resonance (NMR) spectroscopy or wet chemical fractionation, and could be useful for characterizing complex DOM chemistry. However, only 1 % of DOM is estimated to be fluorescent, and the utility of UV and fluorescent spectroscopy for DOM characterization needs to be further investigated. This dissertation applied UV and fluorescent spectroscopy to examine hydrologic and land cover controls on DOM chemistry in streams of 45 catchments in the forested headwaters and a mixed landscape of the Willamette River Basin, Oregon, based on two years of monitoring. This dissertation contributes three major findings. First, freezing of water alters DOM chemistry by preferentially precipitating aromatic DOM. Second, UV and fluorescent spectroscopy was able to discriminate DOM delivered from highly processed, proteinrich deep subsurface sources during dry seasons especially in forested headwater streams of the H. J. Andrews Experimental Forest (HJA), where nitrogen inputs are very low. In addition, fluorescent DOM chemistry differed among watersheds with varying forest management history. Third, although fluorescent DOM in a headwater forested system differed among land use history, fluorescent DOM composition did not vary among streams draining a well-mixed landscape of urban, pasture/hay, forest, and agricultural land cover types in the central Willamette River Basin, where nitrogen inputs to streams are relatively high. Dissolved organic carbon (DOC) concentration decreased and the fluorescent index indicated an increase in terrestrial sources of DOM from small (1st and 2nd order) to large (4th to 6th order) streams. A protein-like DOM component that was detected in the headwater forested study site (HJA) was not detected in stream samples from the middle basin study site. These findings indicate that in-stream respiration, fueled by nutrient additions from agriculture runoff, consumes bioavailable, labile DOM (proteins) preferentially relative to more recalcitrant, terrestrial sources of DOM along water flow paths from headwater streams to major rivers. This study shows the clear applicability of the fluorescent characterization of DOM in identifying hydrologic and landscape controls as well as varying DOM chemistry and functions throughout watershed ecosystems. Title: Hydrologic and Land Cover Effects on Sources and Fate of In-Stream Fluorescent Dissolved Organic Matter Author: Lee, Baek Soo P. Dissolved organic matter (DOM) is a critical component of the carbon cycle linking terrestrial and aquatic ecosystems. Although many factors influence DOM fluxes and quality in rivers, controls on DOM compositions in catchments of the western U.S. are poorly understood. UV and fluorescent spectroscopy is a simpler, faster, and less expensive DOM fingerprinting technique compared to techniques, such as nuclear magnetic resonance (NMR) spectroscopy or wet chemical fractionation, and could be useful for characterizing complex DOM chemistry. However, only 1 % of DOM is estimated to be fluorescent, and the utility of UV and fluorescent spectroscopy for DOM characterization needs to be further investigated. This dissertation applied UV and fluorescent spectroscopy to examine hydrologic and land cover controls on DOM chemistry in streams of 45 catchments in the forested headwaters and a mixed landscape of the Willamette River Basin, Oregon, based on two years of monitoring. This dissertation contributes three major findings. First, freezing of water alters DOM chemistry by preferentially precipitating aromatic DOM. Second, UV and fluorescent spectroscopy was able to discriminate DOM delivered from highly processed, proteinrich deep subsurface sources during dry seasons especially in forested headwater streams of the H. J. Andrews Experimental Forest (HJA), where nitrogen inputs are very low. In addition, fluorescent DOM chemistry differed among watersheds with varying forest management history. Third, although fluorescent DOM in a headwater forested system differed among land use history, fluorescent DOM composition did not vary among streams draining a well-mixed landscape of urban, pasture/hay, forest, and agricultural land cover types in the central Willamette River Basin, where nitrogen inputs to streams are relatively high. Dissolved organic carbon (DOC) concentration decreased and the fluorescent index indicated an increase in terrestrial sources of DOM from small (1st and 2nd order) to large (4th to 6th order) streams. A protein-like DOM component that was detected in the headwater forested study site (HJA) was not detected in stream samples from the middle basin study site. These findings indicate that in-stream respiration, fueled by nutrient additions from agriculture runoff, consumes bioavailable, labile DOM (proteins) preferentially relative to more recalcitrant, terrestrial sources of DOM along water flow paths from headwater streams to major rivers. This study shows the clear applicability of the fluorescent characterization of DOM in identifying hydrologic and landscape controls as well as varying DOM chemistry and functions throughout watershed ecosystems. Close

• 20. [Article] Response of soil microbial communities to physical and chemical disturbances: implications for soil quality and land use sustainability

  The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes ...

  Citation × Citation Citation Abstract Copy Title: Response of soil microbial communities to physical and chemical disturbances: implications for soil quality and land use sustainability Author: Chaer, Guilherme M. The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to evaluate differences in the stability of soil enzymes (laccase, cellulase and fluorescein diacetate hydrolysis) and microbial community composition as determined by phospholipid fatty acid (PLFA) analysis. The conversion of land use from forest to agriculture resulted in a new microbial community that was less functionally stable. Loss of stability was indicated by the reduced resilience of laccase and cellulase activities in the agricultural soil, which suggested a less diverse community of microorganisms capable of producing these enzymes. The second study examined changes in microbial community composition and diversity that occurred across a gradient of soil disturbance. Disturbances were simulated by tillage events applied at different intensities to a 12-year-old fallow area. These treatments caused degradation of several soil physico-chemical properties, and alterations in microbial structure based on PLFA and terminal restriction fragment length polymorphism (T-RFLP) analyses, and in metabolic potential based on community level physiological profiles (CLPPs). Multivariate ordination of soil properties revealed the formation of a linear gradient of soil degradation that was significantly correlated with CLPPs, but not with T-RFLP and PLFA profiles. Nevertheless, changes observed in microbial community structure were significantly associated with decreases in soil organic C and field hydraulic conductivity. The third study demonstrated that undisturbed forest soils from western Oregon express an equilibrium between soil organic matter and biochemical properties. A model fitted through multiple regression analysis showed that phosphatase activity and microbial biomass were able to explain 97% of the soil organic C in these soils. This equilibrium was disrupted when a soil from an old-growth site was submitted to chemical stresses (Cu addition or pH alteration) and physical disturbances (wet-dry or freeze-thaw cycles). The magnitude of this disruption was consistently expressed by the ratio between soil C predicted by the model (Cp), and soil C that was measured (Cm). This ratio is proposed as biochemically-based index of soil quality. Title: Response of soil microbial communities to physical and chemical disturbances: implications for soil quality and land use sustainability Author: Chaer, Guilherme M. The objectives of this thesis were to evaluate the responses of soil microbial communities to physical and chemical disturbances, and associate these responses with soil functional stability and changes in soil quality. The first study consisted of application of heat shocks (HS) to soils with contrasting land use history to evaluate differences in the stability of soil enzymes (laccase, cellulase and fluorescein diacetate hydrolysis) and microbial community composition as determined by phospholipid fatty acid (PLFA) analysis. The conversion of land use from forest to agriculture resulted in a new microbial community that was less functionally stable. Loss of stability was indicated by the reduced resilience of laccase and cellulase activities in the agricultural soil, which suggested a less diverse community of microorganisms capable of producing these enzymes. The second study examined changes in microbial community composition and diversity that occurred across a gradient of soil disturbance. Disturbances were simulated by tillage events applied at different intensities to a 12-year-old fallow area. These treatments caused degradation of several soil physico-chemical properties, and alterations in microbial structure based on PLFA and terminal restriction fragment length polymorphism (T-RFLP) analyses, and in metabolic potential based on community level physiological profiles (CLPPs). Multivariate ordination of soil properties revealed the formation of a linear gradient of soil degradation that was significantly correlated with CLPPs, but not with T-RFLP and PLFA profiles. Nevertheless, changes observed in microbial community structure were significantly associated with decreases in soil organic C and field hydraulic conductivity. The third study demonstrated that undisturbed forest soils from western Oregon express an equilibrium between soil organic matter and biochemical properties. A model fitted through multiple regression analysis showed that phosphatase activity and microbial biomass were able to explain 97% of the soil organic C in these soils. This equilibrium was disrupted when a soil from an old-growth site was submitted to chemical stresses (Cu addition or pH alteration) and physical disturbances (wet-dry or freeze-thaw cycles). The magnitude of this disruption was consistently expressed by the ratio between soil C predicted by the model (Cp), and soil C that was measured (Cm). This ratio is proposed as biochemically-based index of soil quality. Close