people

LEMMA Team Detail

Janet Ohmann
Research Associate
Forest Landscape Ecologist
Dept. of Forest Ecosystems and Society
Oregon State University

Emeritus Scientist
Pacific Northwest Research Station
USDA Forest Service
Mailing address:
3200 SW Jefferson Way
Corvallis, OR 97331
Phone:
(541) 750-7487
Email:

Educational Background

B.A., 1979 (botany), Duke University, Durham, NC
M.F., 1980 (forest ecology), Duke University School of Forestry and Environmental Studies, Durham, NC
Ph.D., 1996 (forest ecology), Oregon State University, Corvallis, OR

Research Interests

Understanding broad-scale patterns and dynamics of forest vegetation, and relations with environment and disturbance; ecological basis for inventory and monitoring; regional gradients in plant community composition and structure; regional distribution of large dead wood and implications for wildlife; tree-level processes of mortality, decay, and fall; predictive mapping of vegetation and fuels using field plots, satellite imagery, and GIS; application of computer gaming technology to visualize and query regional spatial data.

Biography

Janet has been with PNW Research Station since 1981. From 1981-1991 she was a research forester with the Forest Inventory and Analysis Program in Portland, Oregon. From 1991 to 2009, Janet was a research forest ecologist in the Ecosystem Processes Program in Corvallis, Oregon. She is now a member of the Vegetation Monitoring and Remote Sensing Team in the Resource Monitoring and Assessment Program. She has held an affiliate faculty position in the Department of Forest Science (now Forest Ecosystems and Society), Oregon State University, since 1996. Outside of work, Janet enjoys backcountry and international travel, time with friends and family, chasing varmints from her garden, and restoring native habitats on a small patch of ground.

Refereed Publications

Henderson, EB, JL Ohmann, MJ Gregory, HM Roberts, HSJ Zald. In press. Species distribution modelling for plant communities: stacked single species or multivariate modelling approaches?. Applied Vegetation Science.
Ohmann, JL, MJ Gregory, HM Roberts. In press. Scale considerations for integrating forest inventory plot data and satellite image data for regional forest mapping. Remote Sensing of Environment.
Zald, HSJ, JL Ohmann, HM Roberts, MJ Gregory, EB Henderson, R McGaughey, J Braaten. 2014. Influence of lidar, Landsat imagery, disturbance history, plot location accuracy, and plot size on accuracy of imputation maps of forest composition and structure. Remote Sensing of Environment 143:26-38.
Ohmann, JL, MJ Gregory, HM Roberts, WB Cohen, RE Kennedy, Z Yang. 2012. Mapping change of older forest with nearest-neighbor imputation and Landsat time-series. Forest Ecology and Management 272:13-25.
Ohmann, JL, MJ Gregory, EB Henderson, HM Roberts. 2011. Mapping gradients of community composition with nearest-neighbour imputation: extending plot data for landscape analysis. Journal of Vegetation Science 22(4):660-676.
Marcot, BG, JL Ohmann, KL Mellen-McLean, KW Waddell. 2010. Synthesis of regional wildlife and vegetation field studies to guide management of standing and down dead trees. Forest Science 56(4):391-404.
Václavík, T, A Kanaskie, E Hansen, JL Ohmann, R Meentemeyer. 2010. Predicting potential and actual distribution of sudden oak death in Oregon: Prioritizing landscape contexts for early dectection and eradication of disease outbreaks. Forest Ecology and Management 260:1026-1035.
Pierce Jr., KB, JL Ohmann, MC Wimberly, MJ Gregory, JS Fried. 2009. Mapping wildland fuels and forest structure for land management: a comparison of nearest-neighbor imputation and other methods. Canadian Journal of Forest Research 39(10):1901-1916.
Nonaka, E, TA Spies, MC Wimberly, JL Ohmann. 2007. Historical range of variability in live and dead wood biomass: a regional-scale simulation study. Canadian Journal of Forest Research 37(11):2349-2364.
Ohmann, JL, MJ Gregory, TA Spies. 2007. Influence of environment, disturbance, and ownership on forest vegetation of Coastal Oregon. Ecological Applications 17(1):18-33.
Spies, TA, KN Johnson, KM Burnett, JL Ohmann, BC McComb, GH Reeves, P Bettinger, JD Kline, B Garber-Yonts. 2007. Cumulative ecological and socioeconomic effects of forest policies in coastal Oregon. Ecological Applications 17(1):5-17.
Kerns, BK, JL Ohmann. 2004. Evaluation and prediction of shrub cover in coastal Oregon forests. Ecological Indicators 4(2):83-98.
Marcot, BG, G Gunderson, KL Mellen, JL Ohmann. 2004. DecAID Advisor: A tool for managing snags, down wood and wood decay in PNW forests. Western Forester, Society of American Foresters 49(4):12-13.
Wimberly, MC, JL Ohmann. 2004. A multi-scale assessment of human and environmental constraints on forest land cover change on the Oregon (USA) coast range. Landscape Ecology 19(6):631-646.
Ohmann, JL, MJ Gregory. 2002. Predictive mapping of forest composition and structure with direct gradient analysis and nearest-neighbor imputation in coastal Oregon, USA. Canadian Journal of Forest Research 32(4):725-741.
Waring, RH, NC Coops, JL Ohmann, DA Sarr. 2002. Interpreting woody plant richness from seasonal ratios of photosynthesis. Ecology 83(11):2964-2970.
Sinton, DS, JA Jones, JL Ohmann, FJ Swanson. 2000. Windthrow disturbance, forest composition, and structure in the Bull Run Basin, Oregon. Ecology 81(9):2539-2556.
Ohmann, JL, TA Spies. 1998. Regional gradient analysis and spatial pattern of woody plant communities of Oregon forests. Ecological Monographs 68(2):151-182.
Ohmann, JL, WC McComb, AA Zumrawi. 1994. Snag abundance for primary cavity-nesting birds on nonfederal forest lands in Oregon and Washington. Wildlife Society Bulletin 22:607-620.
Hansen, AJ, TA Spies, FJ Swanson, JL Ohmann. 1991. Conserving biodiversity in managed forests. BioScience 41:382-392.

Peer-Reviewed Publications

Moeur, M, JL Ohmann, RE Kennedy, WB Cohen, Z Yang, MJ Gregory, HM Roberts, M Fiorella. 2011. Northwest Forest Plan -- status and trends of late-successional and old-growth forests from 1994 to 2008. PNW-GTR-853, Pacific Northwest Research Station, USDA Forest Service, Portland, OR.

Technical Reports

Pflugmacher, D, WB Cohen, JL Ohmann, RE Kennedy. 2011. Mapping current conditions and modeling the dynamic responses of riparian vegetation and salmon habitat in Oregon. Grant Report Mapping Component: OWEB # 208-8007-5781.
Grossmann, EB, JL Ohmann, J Kagan, HK May, MJ Gregory. 2010. Mapping ecological systems with a random forest model: tradeoffs between errors and bias. USGS Gap Analysis Bulletin, No. 17; February 2010; pp 16-22.
Grossmann, EB, JL Ohmann, MJ Gregory, HK May. 2009. Nationwide Forest Imputation Study (NaFIS) - Western Team final report. Final Report of the Nationwide Forest Imputation Study (NaFIS).
Grossmann, EB, J Kagan, JL Ohmann, HK May, MJ Gregory, C Tobalske. 2008. Final report on land cover mapping methods, map zones 2 and 7, Pacific Northwest ReGAP. Institute for Natural Resources, Oregon State University, Corvallis, OR.
Kagan, J, JL Ohmann, MJ Gregory, C Tobalske. 2008. Land cover map for map zones 8 and 9 developed from SAGEMAP, GNN, and SWReGAP: A pilot for NWGAP. USGS Gap Analysis Bulletin, No. 15; February 2008; pp 15-19.
Ohmann, JL, MJ Gregory, TM Holt. 2007. Innovative, 3-D, interactive, and immersive techniques for visualizing, querying, and understanding regional maps of forest vegetation, fuels, and fire risk. Final Report to the Governing Board, Joint Fire Science Program, Project 05-4-1-12.
Kagan, J, JL Ohmann, MJ Gregory, C Tobalske, JC Hak, JS Fried. 2006. Final report on land cover mapping methods, map zones 8 and 9, Pacific Northwest ReGAP. Institute for Natural Resources, Oregon State University, Corvallis, OR.
Ohmann, JL, MC Wimberly, JS Fried, KB Pierce Jr., MJ Gregory. 2005. A novel approach to regional fuel mapping: linking inventory plots with satellite imagery and GIS databases using the Gradient Nearest Neighbor method. Final report to the Governing Board, Joint Fire Science Program; Project 01-1-4-09.
Mellen, KL, BG Marcot, JL Ohmann, KW Waddell, EA Willhite, BB Hostetler, SA Livingston, C Ogden. 2002. DecAID: A decaying wood advisory model for Oregon and Washington. USDA Forest Service General Techical Report PSW-GTR-181.
Ohmann, JL, KW Waddell. 2002. Regional patterns of dead wood in forested habitats of Oregon and Washington. In: Laudenslayer, WF Jr., PJ Shea, BE Valentine, CP Weatherspoon, TE Lisle; tech. coords. Proceedings of the symposium on the ecology and management of dead wood in western forests; 1999 November 2-4; Reno, NV. Gen. Tech. Rep. PSW-GTR-181. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture;535-560.
Spies, TA, KN Johnson, P Bettinger, WC McComb, JL Ohmann, GH Reeves. 2002. Challenges to integrating wood production, biodiversity, and other socioeconomic values at broad scales: an example from coastal Oregon. In Johnson, AC, RW Haynes, RA Monserud; eds. Gen. Tech. Rep. PNW-GTR-563. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; p. 13-25.
Garman, SL, SA Acker, JL Ohmann, TA Spies. 1995. Asymptotic height-diameter equations for twenty-four tree species in western Oregon. Research Contribution 10. Corvallis, OR: Oregon State University, College of Forestry, Forest Research Laboratory; 22 p.
Ohmann, JL. 1992. Wildlife habitats of the north coast of California: New techniques for extensive forest inventory. USDA Forest Service Research Paper PNW-RP-440.

Other Non-Refereed Publications

Václavík, T, A Kanaskie, E Goheen, JL Ohmann, E Hansen, R Meentemeyer. 2010. Mapping the risk of sudden oak death in Oregon: prioritizing locations for early detection and eradication. In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M. Proceedings of the Sudden Oak Death Fourth Science Symposium. Gen. Tech. Rep. PSW-GTR-229. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 126-132.
Moeur, M, JL Ohmann, M Hemstrom, T Burcsu, J Merzenich. 2009. Projecting watershed condition with Interagency Mapping and Assessment Project (IMAP) vegetation data and landscape models. In Bayer, J.M., and Schei, J.L., eds., PNAMP Special Publication: Remote Sensing Applications for Aquatic Resource Monitoring, Pacific Northwest Aquatic Monitoring Partnership, Cook, Washington, chap. 11, p. 83-90.
Holt, TM, MJ Gregory, JL Ohmann. 2007. GNNViz User Guide. Appendix 1 of the JFSP Final Report; Project 05-4-1-12.
Hemstrom, M, J Merzenich, JL Ohmann, R Singleton. 2006. Integrating natural disturbances and management activities to examine risks and opportunities in the Central Oregon Landscape Analysis. Advances in Threat Assessment Conference Proceedings; USDA Forest Service Southern Research Station; Boulder, CO July 18-20, 2006; Published online at: http://www.forestencyclopedia.net/p/p5/p3389/p3390.
Mellen, KL, BG Marcot, JL Ohmann, KW Waddell, SA Livingston, EA Willhite, BB Hostetler, C Odgen, T Dreisbach. 2006. DecAID, the Decayed Wood Advisor for managing snags, partially dead trees, and down wood for biodiversity in forests of Washington and Oregon. http://www.fs.fed.us/r6/nr/wildlife/decaid/; Version 2.0. January 2006.
Pierce Jr., KB, K Brewer, JL Ohmann. 2006. Moderate resolution data and Gradient Nearest Neighbor imputation for regional-national risk assessment. Advances in Threat Assessment Conference Proceedings; USDA Forest Service Southern Research Station; Boulder, CO July 18-20, 2006; Published online at: http://www.forestencyclopedia.net/p/p5/p3389/p3443.
Pierce Jr., KB, JL Ohmann. 2005. Gradient nearest neighbor imputation for mapping forest attributes and variability. Quantitative Techniques for Deriving National-Scale Data; Westminster, CO July 26-28, 2005; USFS General Technical Report (FHTET-2005-12).
Wimberly, MC, JL Ohmann, KB Pierce Jr., MJ Gregory, JS Fried. 2003. A multivariate approach to mapping forest vegetation and fuels using GIS databases, satellite imagery, and forest inventory plots. Proceedings of the Second International Wildland Fire Ecology and Fire Management Congress. Orlando, FL; 16-20 November 2003. American Meteorological Society.
Spies, TA, DE Hibbs, JL Ohmann, GH Reeves, RJ Pabst, FJ Swanson, C Whitlock, JA Jones, BC Wemple, LA Perendes, BA Schrader. 2002. The ecological basis of forest ecosystem management in the Oregon Coast Range. In Hobbs, SD, JP Hayes, RL Johnson, GH Reeves, TA Spies, JC Tappeiner II, GE Wells; eds. Forest and Stream Management in the Oregon Coast Range. Corvallis, OR: Oregon State University Press; 31-67.
Spies, TA, GH Reeves, KM Burnett, WC McComb, KN Johnson, G Grant, JL Ohmann, SL Garman, P Bettinger. 2002. Assessing the ecological consequences of forest policies in a multi-ownership province in Oregon. In Liu, J, WW Taylor; eds. Integrating Landscape Ecology into Natural Resource Management. Cambridge Univ. Press.
Rose, CL, BG Marcot, KL Mellen, JL Ohmann, KW Waddell, DL Lindley, B Schreiber. 2001. Decaying wood in Pacific Northwest forests: concepts and tools for habitat management. In Johnson, DH, TA O'Neil; manag. dirs. Wildlife-Habitat Relationships in Oregon and Washington. Chapter 24. Corvallis, OR: OSU Press; 580-612.
Ohmann, JL. 1996. Regional gradient analysis and spatial pattern of woody plant communities in Oregon. Corvallis, OR: Oregon State University; Ph.D. dissertation; 196 p..
Ohmann, JL, WB Cohen. 1993. Inventories of stand structure: an ecosystem perspective. In Lund, HG, E Landis, T Atterbury; eds. Stand inventory technologies 1992: proceedings of an international multiple resource conference. 1992 September 13-18; Portland, OR. American Society for Photogrammetry and Remote Sensing; 193-203.

Presentations

Gregory, MJ, JL Ohmann, HM Roberts, HSJ Zald, EB Henderson. 2013. Recent advances and applications of nearest neighbors methods for regional-scale forest vegetation mapping in the Pacific Northwest, USA. Landcare Research Seminar: Lincoln, New Zealand; February 2013.
Zald, HSJ, JL Ohmann, HM Roberts, M Gregory, EB Henderson, R McGaughey, RE Kennedy, J Braaten, M Simpson. 2013. Incorporating LiDAR and Landsat disturbance history into nearest neighbor mapping of vegetation composition and structure. USFS Region 6 office for Monitoring Inventory Mapping and LiDAR (MIML) working group: Portland, OR; February 2013.
Henderson, EB, JL Ohmann, MJ Gregory, HM Roberts, HSJ Zald. 2012. All for one or one for all? Mapping many species individually versus simultaneously with random forest. Ecological Society of America Annual Conference: Portland, OR; August 2012.
Ohmann, JL, MJ Gregory, HM Roberts, RE Kennedy, Z Yang, J Braaten, SL Powell, WB Cohen, V Kane, J Lutz. 2012. Mapping change in live and dead forest biomass with Landsat time-series, remeasured plots, and nearest-neighbor imputation. ForestSat 2012: Corvallis, OR; September 2012.
Powell, SL, RE Kennedy, JL Ohmann, WB Cohen, MJ Gregory, HM Roberts, V Kane, J Lutz. 2012. Comparison of biomass allometric approaches for regional scale carbon mapping. ForestSat 2012: Corvallis, OR; September 2012.
Ohmann, JL, MJ Gregory, HM Roberts, RE Kennedy, WB Cohen, Z Yang, M Moeur. 2011. Spatial monitoring of older forest and habitat for the Northwest Forest Plan. National FIA Users Group Meeting: Sacramento, CA; March 2011.
Ohmann, JL, MJ Gregory, HM Roberts, RE Kennedy, Z Yang, M Moeur, WB Cohen. 2011. Landscape context for density management: implications of land ownership and ecological gradients. Conference on state-of-the-art in west-side forest management: Corvallis, OR; October 2011.
Gregory, MJ, EB Grossmann, JL Ohmann, HM Roberts. 2010. The Nationwide Forest Imputation Study (NaFIS): Challenges, results and recommendations from the western United States. Forest Inventory and Analysis Science Symposium: Knoxville, TN; October 2010.
Ohmann, JL, MJ Gregory, HK May, EB Grossmann. 2010. Nearest neighbor mapping of vegetation gradients for landscape analysis and planning. 53rd International Symposium of the International Association for Vegetation Science: Ensenada, Mexico; April 2010.
Ohmann, JL, MJ Gregory, HM Roberts, RE Kennedy, WB Cohen, Z Yang, M Moeur. 2010. Spatial monitoring of late-successional forest habitat over large regions with nearest-neighbor imputation. XXIII International Union of Forest Research Organizations (IUFRO): Seoul, South Korea; August 2010.
Grossmann, EB, JL Ohmann, MJ Gregory, HK May. 2009. Gradients or hierarchies? Which assumptions make a better map?. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Snowbird, UT; April 2009.
Grossmann, EB, JL Ohmann, MJ Gregory, HK May. 2009. Regional vegetation mapping: Making sense of the methods. Workshop on remote sensing for land managers: Redding, CA; June 2009.
Grossmann, EB, JL Ohmann, MJ Gregory, HK May. 2009. Bringing our best data into conservation and restoration planning. California Klamath-Siskiyou Fire Learning Network Workshop: Weaverville, CA; July 2009.
Grossmann, EB, JL Ohmann, MJ Gregory, HK May. 2009. Regional vegetation - methods behind the maps: Gradient Nearest Neighbor and random forest modeling. Information Sharing Workshop, Bureau of Land Management: Salem, OR; April 2009.
Gregory, MJ, JL Ohmann, EB Grossmann, HK May. 2008. Spatial scaling effects of inventory reference data on nearest neighbor model predictions. Forest Inventory and Analysis Symposium: Park City, UT; October 2008.
Gregory, MJ, JL Ohmann, HK May, EB Grossmann, KB Pierce Jr., TM Holt, JS Fried. 2008. Recent advances and applications of nearest neighbors methods for regional-scale forest vegetation modeling. Department of Forest Science Seminar: Corvallis, OR; April 2008.
Gregory, MJ, JL Ohmann, TM Holt. 2008. GNNViz: Immersive and collaborative visualization for landscapes. The Nature Conservancy Climate Change Workshop: Portland, OR; April 2008.
Gregory, MJ, JL Ohmann, TM Holt. 2008. Seeing data with GIS: from paper maps to immersive visualizations. Kids Keynote address to GIS Day: Corvallis, OR; November 2008.
Grossmann, EB, JL Ohmann, J Kagan, KB Pierce Jr., HK May, MJ Gregory. 2008. Random forests and nearest neighbors: Methods for mapping the West Cascades of Oregon. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Madison, WI; April 2008.
Grossmann, EB, JL Ohmann, MJ Gregory, HK May. 2008. Is the World a Gradient, or a Hierarchy of Thresholds? Imputing Forest Composition and Structure Variables in the Pacific Northwest. Forest Inventory and Analysis Symposium: Park City, UT; October 2008.
 Moeur, M, JL Ohmann, M Hemstrom, T Burcsu, J Merzenich. 2008. The Interagency Mapping and Assessment Project (IMAP): integrating existing vegetation maps and models of vegetation dynamics for watershed assessment.. ASPRS 2008 Annual Conference: Portland, OR; May 2008.
Ohmann, JL, M Moeur, M Hemstrom, T Burcsu, J Merzenich, MJ Gregory, HK May, EB Grossmann. 2008. Integrating forest inventory data, vegetation maps, and models of vegetation dynamics to support landscape analysis and planning: the IMAP story. Forest Inventory and Analysis Symposium: Park City, UT; October 2008.
 Ohmann, JL, MJ Gregory, HK May, EB Grossmann. 2008. Gradient Nearest Neighbor (GNN) maps of forest vegetation: accuracy assessment and uncertainty. Interagency Mapping and Assessment Project (IMAP) Users' Group: Portland, OR; February 2008.
 Powell, SL, RE Kennedy, SP Healey, KB Pierce Jr., WB Cohen, GG Moisen, JL Ohmann. 2008. Comparison of methods to model aboveground biomass for derivation of 20+ year trajectories. NASA Carbon Cycle and Ecosystems Joint Science Workshop: College Park, MD; April 2008.
Grossmann, EB, JL Ohmann, J Kagan, KB Pierce Jr., HK May, MJ Gregory. 2007. Models for ecological systems map building: random forest and gradient nearest neighbor. Which one works best?. National GAP Analysis Program Conference: Asheville, NC; September 2007.
Ohmann, JL, KB Pierce Jr., EB Grossmann, MJ Gregory, HK May, TM Holt. 2007. Current Vegetation Mapping in Western Oregon. Presented at: USFS Klamath Falls Ranger District: Klamath Falls, OR; June 2007.
Ohmann, JL, MJ Gregory, KB Pierce Jr., HK May, EB Grossmann. 2007. Seeing the forest and the trees: harnessing GIS to map forests of the Pacific Northwest. Keynote address to GIS Day: Corvallis, OR; November 2007.
Gregory, MJ, JL Ohmann, BC McComb. 2006. Sensitivity of wildlife habitat capability models to spatial resolution of underlying mapped vegetation data. 2006 Nearest Neighbors Workshop - Meeting in the Middle: Minneapolis, MN; August 2006.
Ohmann, JL, JS Fried, KB Pierce Jr., MJ Gregory, MC Wimberly. 2006. Mapping forest vegetation and fuels with Gradient Nearest Neighbor imputation. Yosemite Fire Science Symposium: Yosemite National Park, CA; May 2006.
Ohmann, JL, KB Pierce Jr., EB Grossmann, MJ Gregory, HK May, TM Holt. 2006. Mapping current vegetation in the Pacific Coast States with GNN, CART, and other tricks. Workshop and field tour with NF, ODF, TNC, and R6: Sycan Marsh Research Station, OR; September 2006.
Ohmann, JL, MJ Gregory, KB Pierce Jr., TM Holt, HK May. 2006. Mapping forest species and plant communities with Gradient Nearest Neighbor imputation. 2006 Nearest Neighbors Workshop - Meeting in the Middle: Minneapolis, MN; August 2006.
Pierce Jr., KB, JL Ohmann. 2006. Variance of similar neighbors compared to random imputation. 2006 Nearest Neighbors Workshop - Meeting in the Middle: Minneapolis, MN; August 2006.
 Fried, JS, JL Ohmann, KB Pierce Jr., MC Wimberly, MJ Gregory. 2005. A mid-scale approach to mapping forest fuel and fire hazards at the wildland-urban interface by imputation and modeling of inventory plot data. Seventh Annual Forest Inventory and Analysis Science Symposium: Portland, ME; October 2005.
Gregory, MJ, KB Pierce Jr., JL Ohmann. 2005. Gradient Nearest Neighbor imputation for local scale basal area mapping: FIA 2005 Symposium interpolation contest. Seventh Annual Forest Inventory and Analysis Science Symposium: Portland, ME; October 2005.
Ohmann, JL. 2005. Gradient Nearest Neighbor imputation maps for landscape analysis in the Pacific Northwest. National Gap Analysis Conference and Interagency Symposium: Reno, NV; December 2005.
 Ohmann, JL, KB Pierce Jr., MJ Gregory, JS Fried. 2005. Gradient Nearest Neighbor imputation based on FIA plots - useful tool or lying with maps?. Seminar at Forestry Sciences Lab: Portland, OR; August 2005.
 Pierce Jr., KB, JL Ohmann, MJ Gregory, JS Fried. 2005. Regional vegetation mapping in support of risk assessment. Workshop on regional risk assessment methodologies. Organized by Western Wildlands Environmental Threat Assessment Center, USDA Forest Service: Portland, OR; September 2005.
 Pierce Jr., KB, JL Ohmann, MJ Gregory, JS Fried. 2005. Gradient Nearest Neighbor imputation mapping in support of risk assessment. Workshop for evaluating quantitative techniques for deriving national scale data for assessing and mapping risk; organized by Forest Health Technology Enterprise Team, Forest Health Protection, USDA Forest Service: Fort Collins, CO; July 2005.
 Pierce Jr., KB, MC Wimberly, JL Ohmann, MJ Gregory, JS Fried. 2005. What is the probability that I-30 runs through Fort Worth? Incorporating uncertainty into map use. Annual meeting of the Society of American Foresters: Fort Worth, TX; October 2005.
 Ohmann, JL, KB Pierce Jr., MJ Gregory, MC Wimberly, JS Fried. 2004. A novel approach to regional fuel mapping: linking inventory plots with satellite imagery and GIS databases using the Gradient Nearest Neighbor method. Joint Fire Science Program Principal Investigator Workshop: Phoenix, AZ; April 2004.
 Pierce Jr., KB, JL Ohmann, MJ Gregory. 2004. Assessing spatial uncertainty in landscape vegetation maps created with imputation procedures. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Las Vegas, NV; April 2004.
 Wimberly, MC, C Avery, JL Ohmann, KB Pierce Jr., MJ Gregory, JS Fried. 2004. Influences of landscape structure, drought, and wind on crown fire spread in forest landscapes. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Las Vegas, NV; April 2004.
 Ohmann, JL, KB Pierce Jr., MJ Gregory, MC Wimberly, JS Fried. 2003. A novel approach to regional fuel mapping: linking inventory plots with satellite imagery and GIS databases using the Gradient Nearest Neighbor method. Joint Fire Science Program Principal Investigator Workshop: Phoenix, AZ; March 2003.
 Ohmann, JL, KB Pierce Jr., MJ Gregory, S Danskin, MC Wimberly, JS Fried. 2003. Mapping live and dead forest fuels at the ecoregion scale in coastal Oregon with Landsat imagery and forest inventory plots. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Banff, AB; April 2003.
 Ohmann, JL, MJ Gregory, TA Spies. 2003. Linking field plot, satellite imagery, and environmental data to assess regional patterns of vegetation biodiversity. Annual meeting of the Society of American Foresters: Buffalo, NY; October 2003.
 Ohmann, JL, MJ Gregory, TA Spies. 2003. Predictive vegetation mapping and current vegetation biodiversity in coastal Oregon. Botany and Plant Pathology Departmental seminar: Corvallis, OR; February 2003.
 Wimberly, MC, JL Ohmann, KB Pierce Jr., MJ Gregory, JS Fried. 2003. A multivariate approach to mapping forest vegetation and fuels using GIS databases, satellite imagery, and forest inventory plots. Fifth Symposium on Fire and Forest Meteorology and 2nd International Wildland Fire Ecology and Fire Management Congress: Orlando, FL; November 2003.
 Ohmann, JL, MJ Gregory. 2002. Predictive mapping of forest composition and structure with direct gradient analysis and nearest-neighbor imputation (the Gradient Nearest Neighbor method). Focus session at the Joint Meeting of Fourth Annual Forest Inventory and Analysis Science Symposium and the Southern Forest Mensurationists: New Orleans, LA; November 2002.
 Ohmann, JL, TA Spies, MJ Gregory, KN Johnson. 2002. Vegetation biodiversity in coastal Oregon forests. A Multi-ownership Assessment of Forests and Watersheds of the Oregon Coast Range. Presented as part of an all-day symposium and workshop of invited stakeholders and landowners. Organized by the Coastal Landscape Analysis and Modeling Study (CLAMS): Corvallis, OR; June 2002.
 Gregory, MJ, JL Ohmann. 2000. Predictive mapping of forest composition and structure using the Gradient Nearest Neighbor Method. Willamette Valley GIS Users Group: Corvallis, OR; November 2000.
 Ohmann, JL, MJ Gregory, JE Gray. 1999. Linking satellite, plot, and environmental data to map patterns of species composition across Pacific Northwest forests. Special session at annual meeting of the American Society of Photogrammetry and Remote Sensing: Portland, OR; May 1999.

Posters

Ohmann, JL, MJ Gregory, HM Roberts, RE Kennedy, WB Cohen, Z Yang, M Moeur, M Fiorella. 2012. Mapping change of older forest with permanent plots, Landsat time series, and nearest-neighbor imputation. Ecological Society of America Annual Conference: Portland, OR; August 2012.
Roberts, HM, JL Ohmann, MJ Gregory, EB Henderson. 2012. Gradient nearest neighbor forest vegetation maps for landscape analysis and planning. ForestSat 2012: Corvallis, OR; September 2012.
Zald, HSJ, JL Ohmann, HM Roberts, R McGaughey, MJ Gregory, RE Kennedy. 2012. Influence of inventory plot and Landsat imagery positional accuracies on nearest-neighbor (NN) imputation maps of vegetation composition and structure. ForestSat 2012: Corvallis, OR; September 2012.
Gregory, MJ, JL Ohmann, HM Roberts, R Riemann. 2011. Nearest neighbor vegetation maps for landscape analysis and conservation planning: are they good enough, and how will I know?. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Portland, OR; April 2011.
Ohmann, JL, MJ Gregory, HM Roberts, RE Kennedy, WB Cohen, Z Yang, M Moeur, M Fiorella. 2011. Spatial monitoring of forest landscape dynamics with permanent plots, Landsat time-series and nearest-neighbor imputation. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Portland, OR; April 2011.
Roberts, HM, JL Ohmann, MJ Gregory, EB Henderson. 2011. Gradient nearest neighbor forest vegetation maps for landscape analysis and planning. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Portland, OR; April 2011.
Roberts, HM, JL Ohmann, MJ Gregory, EB Grossmann. 2010. Nearest-neighbor forest vegetation maps from FIA plots and geospatial data for landscape analysis and planning in the Pacific Northwest (and beyond). Forest Inventory and Analysis Symposium: Knoxville, TN; October 2010.
Grossmann, EB, JL Ohmann, HK May, MJ Gregory. 2009. Mapping mountain hemlock and pinpointing ponderosa pine: Imputation mapping species distributions in Western Oregon. North American Forest Ecology Workshop: Logan, UT; June 2009.
Hagar, J, P Haggerty, J Kertis, JL Ohmann. 2009. Oregon white oak: An ecosystem on the brink - Where's the science?. 8th Biennial USGS Pacific Northwest Science Conference: Portland, OR; March 2009.
Ohmann, JL, MJ Gregory, HK May, EB Grossmann, RE Kennedy, WB Cohen, Z Yang, E Pfaff, M Moeur. 2009. Spatial monitoring of disturbance and late-succesional forest dynamics in the Pacific Northwest. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Snowbird, UT; April 2009.
Gregory, MJ, JL Ohmann, TM Holt. 2008. An application of computer gaming technology to visualize, query, and understand forest landscapes. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Madison, WI; April 2008.
Grossmann, EB, JL Ohmann, J Kagan, MJ Gregory, HK May. 2008. Context-dependent hierarchy of plant community predictors from the Oregon Coast Range to the eastern slopes of the Cascade Mountains. Ecological Society of America Annual Meeting: Milwaukee, WI; August 2008.
Ohmann, JL, MJ Gregory, JD Kline, RJ Alig, HK May, EB Grossmann. 2008. Implications of social and ecological gradients for conservation planning in large, multi-ownership, forested landscapes. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Madison, WI; April 2008.
Davidson, A, T Miewald, JL Ohmann, J Kagan, EB Grossmann, T Sajwaj, J Aycrigg, S Lennartz, S McDonough. 2007. Methods and status of land cover mapping for the Northwest Gap Analysis Project. National GAP Analysis Program Conference: Asheville, NC; September 2007.
Grossmann, EB, JL Ohmann, J Kagan, KB Pierce Jr., HK May, MJ Gregory. 2007. A tale of two techniques: Gradient Nearest Neighbor and random forest for mapping ecological systems in Oregon's Western Cascades. North American Forest Ecology Workshop: Vancouver, BC; June 2007.
 Fried, JS, JL Ohmann, MC Wimberly, KB Pierce Jr., MJ Gregory. 2006. Tapping the forest inventory for spatially continuous estimates of fuels and fire potential: the GNNFire approach. First Fire Behavior and Fuels Conference: Fuels Management - how to measure success: Portland, OR; March 2006.
 Ohmann, JL, MJ Gregory, KB Pierce Jr., MC Wimberly, JS Fried. 2005. A novel approach to regional fuel mapping: linking inventory plots with satellite imagery and GIS databases using the Gradient Nearest Neighbor method. Poster presented at Joint Fire Science Program Principal Investigator Workshop: San Diego, CA; November 2005.
Ohmann, JL, MJ Gregory, KB Pierce Jr., MC Wimberly, JS Fried. 2005. Mapping forest vegetation and fuels with Gradient Nearest Neighbor imputation in three western ecoregions. JFSP Annual Meeting: San Diego, CA; October 2005.
Gregory, MJ, JL Ohmann. 2004. Spatial modeling of regional vegetation using field plots and geospatial information: a software framework for the Gradient Nearest Neighbor method. College of Forestry Spatial Data Management Group: Corvallis, OR; April 2004.
Gregory, MJ, JL Ohmann. 2004. Spatial modeling of regional vegetation using field plots and geospatial information: a software framework for the Gradient Nearest Neighbor method. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Las Vegas, NV; April 2004.
Nonaka, E, TA Spies, MC Wimberly, JL Ohmann. 2004. Historical range of variability (HRV) in biomass dynamics and stand fire history: a simulation modeling approach. Annual Meeting of the Ecological Society of America: Portland, OR; August 2004.
Pierce Jr., KB, JL Ohmann, MJ Gregory, MC Wimberly, JS Fried. 2004. Mapping forests of the Pacific Northwest: structure, species and uncertainty. Ecological Society of America Annual Meeting: Portland, OR; August 2004.
 Wimberly, MC, C Avery, JL Ohmann, KB Pierce Jr., MJ Gregory, JS Fried. 2004. Landscape connectivity and the potential for catastrophic fire in forested landscapes. Ecological Society of America Annual Meeting: Portland, OR; August 2004.
 Hicks, WT, ME Harmon, JL Ohmann, MJ Gregory, B McCune, SD Berryman, E Martin, L Geiser. 2003. Mapping the abundance and activity of two symbiotic nitrogen fixers in western Oregon. North American Forest Ecology Workshop: Corvallis, OR; June 2003.
Ohmann, JL, TA Spies, MJ Gregory, KN Johnson. 2003. Distribution of vegetation biodiversity across a continuum of land ownership and management emphasis in coastal Oregon. North American Forest Ecology Workshop: Corvallis, OR; June 2003.
 Ohmann, JL. 2002. Snag dynamics in Pacific Northwest forests. Forest Health Monitoring National Meeting: New Orleans, LA; February 2002.
Ohmann, JL, TA Spies, MJ Gregory, KN Johnson. 2002. Distribution of vegetation biodiversity across a continuum of land ownership and management emphasis in coastal Oregon. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Lincoln, NE; April 2002.
 Hudak, AT, MJ Gregory, JL Ohmann, M Moeur, MA Lefsky, WB Cohen. 2001. Comparison of two methods for mapping forest structure from inventory plot and environmental data in Western Oregon. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Tempe, AZ; April 2001.
 Ohmann, JL, MJ Gregory. 2001. How does spatial resolution affect Gradient Nearest Neighbor vegetation maps?. Symposium: A landmark assessment of Oregon's forest sustainability: Corvallis, OR; October 2001.
 Ohmann, JL, MJ Gregory. 2001. How does spatial resolution affect Gradient Nearest Neighbor vegetation maps?. US Regional Association of the International Association of Landscape Ecology: Tempe, AZ; April 2001.
 Ohmann, JL, MJ Gregory. 2001. Predictive mapping of forest composition and structure using direct gradient analysis and nearest-neighbor imputation. North American Forest Ecology Workshop: Duluth, MN; June 2001.
 Ohmann, JL, MJ Gregory. 2001. Predictive mapping of forest composition and structure using direct gradient analysis and nearest-neighbor imputation. Symposium: A landmark assessment of Oregon's forest sustainability: Corvallis, OR; October 2001.
Wimberly, MC, JL Ohmann. 2001. Spatial patterns of forest landscape change in the Oregon coast range between 1936 and 1996. Annual Symposium of the U.S. Regional Association of the International Association of Landscape Ecology: Tempe, AZ; April 2001.
Hudak, AT, MJ Gregory, JL Ohmann, M Moeur, MA Lefsky, WB Cohen. 2000. Predictive mapping of tree species basal areas from forest inventory and environmental data: a comparison of two models. Ecological Society of America Annual Meeting: Snowbird, UT; August 2000.
 Ohmann, JL, KW Waddell. 2000. Regional patterns of dead wood in forests of Oregon and Washington, USA. Annual All Scientists Meeting of the Long Term Ecological Research Program: Snowbird, UT; August 2000.
 Ohmann, JL, KW Waddell. 2000. Regional patterns of dead wood in forests of Oregon and Washington, USA. US Regional Association of the International Association of Landscape Ecology Annual Meeting: Fort Lauderdale, FL; April 2000.
 Ohmann, JL, MJ Gregory. 2000. Predictive mapping of forest composition and structure using direct gradient analysis and nearest-neighbor imputation. Ecological Society of America Annual Meeting: Snowbird, UT; August 2000.
 Ohmann, JL, MJ Gregory. 1999. A Nearest Neighbor Method for Mapping Forest Composition in the Oregon Coastal Province. Oregon's Forests at the Millennium: What Might the Future Hold?: Corvallis, OR; September 1999.