Search Results - "Ohmann, Janet L."

Influence of lidar, Landsat imagery, disturbance history, plot location accuracy, and plot size on accuracy of imputation maps of forest composition and structure by Zald, Harold S.J., Ohmann, Janet L., Roberts, Heather M., Gregory, Matthew J., Henderson, Emilie B., McGaughey, Robert J., Braaten, Justin

“…This study investigated how lidar-derived vegetation indices, disturbance history from Landsat time series (LTS) imagery, plot location accuracy, and plot size…”
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Scale considerations for integrating forest inventory plot data and satellite image data for regional forest mapping by Ohmann, Janet L., Gregory, Matthew J., Roberts, Heather M.

“…The integration of satellite image data with forest inventory plot data is a popular approach for mapping forest vegetation over large regions. Several…”
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Quantification of live aboveground forest biomass dynamics with Landsat time-series and field inventory data: A comparison of empirical modeling approaches by Powell, Scott L., Cohen, Warren B., Healey, Sean P., Kennedy, Robert E., Moisen, Gretchen G., Pierce, Kenneth B., Ohmann, Janet L.

“…Spatially and temporally explicit knowledge of biomass dynamics at broad scales is critical to understanding how forest disturbance and regrowth processes…”
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Regional gradient analysis and spatial pattern of woody plant communities of Oregon forests by Ohmann, Janet L., Spies, Thomas A.

“…Knowledge of regional-scale patterns of ecological community structure, and of factors that control them, is largely conceptual. Regional- and local-scale…”
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Imputed forest structure uncertainty varies across elevational and longitudinal gradients in the western Cascade Mountains, Oregon, USA by Bell, David M., Gregory, Matthew J., Ohmann, Janet L.

“…•We examined uncertainty in imputed, mapped predictions of forest structure.•Live tree variables predictions were less uncertain than dead wood and…”
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Mapping gradients of community composition with nearest-neighbour imputation: extending plot data for landscape analysis by Ohmann, Janet L., Gregory, Matthew J., Henderson, Emilie B., Roberts, Heather M.

“…Question: How can nearest-neighbour (NN) imputation be used to develop maps of multiple species and plant communities? Location: Western and central Oregon,…”
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Predicting potential and actual distribution of sudden oak death in Oregon: Prioritizing landscape contexts for early detection and eradication of disease outbreaks by Václavík, Tomáš, Kanaskie, Alan, Hansen, Everett M., Ohmann, Janet L., Meentemeyer, Ross K.

“…▶ iSDM is crucial for predicting potential and actual distribution of forest pathogens. ▶ Potential spread of P. ramorum threatens over 2100 km 2 of forests in…”
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Species distribution modelling for plant communities: stacked single species or multivariate modelling approaches? by Henderson, Emilie B, Ohmann, Janet L, Gregory, Matthew J, Roberts, Heather M, Zald, Harold, Goslee, Sarah

“…AIM: Landscape management and conservation planning require maps of vegetation composition and structure over large regions. Species distribution models (SDMs)…”
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Mapping change of older forest with nearest-neighbor imputation and Landsat time-series by Ohmann, Janet L., Gregory, Matthew J., Roberts, Heather M., Cohen, Warren B., Kennedy, Robert E., Yang, Zhiqiang

“…► We mapped change in older forest using nearest-neighbor and Landsat time-series. ► Net loss of older forest was 4-6%, depending on threshold values applied…”
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How sampling and scale limit accuracy assessment of vegetation maps: A comment on Loehle et al. (2015) by Bell, David M., Gregory, Matthew J., Roberts, Heather M., Davis, Raymond J., Ohmann, Janet L.

“…Accuracy assessments of remote sensing products are necessary for identifying map strengths and weaknesses in scientific and management applications. However,…”
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Imputing Forest Structure Attributes from Stand Inventory and Remotely Sensed Data in Western Oregon, USA by Hudak, Andrew T., Haren, A. Tod, Crookston, Nicholas L., Liebermann, Robert J., Ohmann, Janet L.

“…Imputation is commonly used to assign reference stand observations to target stands based on covariate relationships to remotely sensed data to assign…”
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Influence of environment, disturbance, and ownership on forest vegetation of coastal Oregon by Ohmann, Janet L., Gregory, Matthew J., Spies, Thomas A.

“…Information about how vegetation composition and structure vary quantitatively and spatially with physical environment, disturbance history, and land ownership…”
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Cumulative Ecological and Socioeconomic Effects of Forest Policies in Coastal Oregon by Spies, Thomas A., Johnson, K. Norman, Burnett, Kelly M., Ohmann, Janet L., McComb, Brenda C., Reeves, Gordon H., Bettinger, Pete, Kline, Jeffrey D., Garber-Yonts, Brian

“…Forest biodiversity policies in multi-ownership landscapes are typically developed in an uncoordinated fashion with little consideration of their interactions…”
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A multi-scale assessment of human and environmental constraints on forest land cover change on the Oregon (USA) coast range by WIMBERLY, Michael C, OHMANN, Janet L

“…Human modification of forest habitats is a major component of global environmental change. Even areas that remain predominantly forested may be changed…”
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Synthesis of Regional Wildlife and Vegetation Field Studies to Guide Management of Standing and Down Dead Trees by Marcot, Bruce G, Ohmann, Janet L, Mellen-McLean, Kim L, Waddell, Karen L

“…We used novel methods for combining information from wildlife and vegetation field studies to develop guidelines for managing dead wood for wildlife and…”
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Evaluation and prediction of shrub cover in coastal Oregon forests (USA) by Kerns, Becky K., Ohmann, Janet L.

“…We used data from regional forest inventories and research programs, coupled with mapped climatic and topographic information, to explore relationships and…”
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Interpreting Woody Plant Richness from Seasonal Ratios of Photosynthesis by Waring, Richard H., Coops, Nicholas C., Ohmann, Janet L., Sarr, Daniel A.

“…In forested portions of Oregon, species richness of woody plants on plots 400-500 m2 ranged from 1 to >20. We investigated what might account for this…”
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Windthrow Disturbance, Forest Composition, and Structure in the Bull Run Basin, Oregon by Sinton, Diana S., Jones, Julia A., Ohmann, Janet L., Swanson, Frederick J.

“…This study examined relationships among forest landscape dynamics, environmental factors (climate and landforms), and disturbance history in forests dominated…”
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Scale considerations for integrating forest inventory plot data and satellite image data for regional forest mapping: 2012 ForestSAT by OHMANN, Janet L, GREGORY, Matthew J, ROBERTS, Heather M

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How sampling and scale limit accuracy assessment of vegetation maps: A comment on by Bell, David M., Gregory, Matthew J., Roberts, Heather M., Davis, Raymond J., Ohmann, Janet L.

“…•We examined how bias and resolution of validation data impact map assessment.•Validation plots smaller than pixel resolution underestimate map performance.•To…”
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