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Physical Sciences and Mathematics Commons

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Forest Sciences

Portland State University

2018

Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

Spatial Factor Models For High-Dimensional And Large Spatial Data: An Application In Forest Variable Mapping, Daniel Taylor-Rodríguez, Andrew O. Finley, Abhirup Datta, Chad Babcock, Hans-Erik Andersen, Bruce D. Cook, Douglas C. Morton, Sudipto Banerjee Nov 2018

Spatial Factor Models For High-Dimensional And Large Spatial Data: An Application In Forest Variable Mapping, Daniel Taylor-Rodríguez, Andrew O. Finley, Abhirup Datta, Chad Babcock, Hans-Erik Andersen, Bruce D. Cook, Douglas C. Morton, Sudipto Banerjee

Mathematics and Statistics Faculty Publications and Presentations

Gathering information about forest variables is an expensive and arduous activity. As such, directly collecting the data required to produce high-resolution maps over large spatial domains is infeasible. Next generation collection initiatives of remotely sensed Light Detection and Ranging (LiDAR) data are specifically aimed at producing complete-coverage maps over large spatial domains. Given that LiDAR data and forest characteristics are often strongly correlated, it is possible to make use of the former to model, predict, and map forest variables over regions of interest. This entails dealing with the high-dimensional (∼102 ) spatially dependent LiDAR outcomes over a large number …


Patterns And Drivers Of Recent Disturbances Across The Temperate Forest Biome, Andreas Sommerfeld, Cornelius Senf, Brian Buma, Anthony W. D'Amato, Tiphaine Despres, Ignacio Díaz-Hormazábal, Shawn Fraver, Lee E. Frelich, Alvaro G. Gutiérrez, Sarah J. Hart, Brian J. Harvey, Hong S. He, Tomáš Hlásny, Andrés Holz, Multiple Additional Authors Oct 2018

Patterns And Drivers Of Recent Disturbances Across The Temperate Forest Biome, Andreas Sommerfeld, Cornelius Senf, Brian Buma, Anthony W. D'Amato, Tiphaine Despres, Ignacio Díaz-Hormazábal, Shawn Fraver, Lee E. Frelich, Alvaro G. Gutiérrez, Sarah J. Hart, Brian J. Harvey, Hong S. He, Tomáš Hlásny, Andrés Holz, Multiple Additional Authors

Geography Faculty Publications and Presentations

Increasing evidence indicates that forest disturbances are changing in response to global change, yet local variability in disturbance remains high. We quantified this considerable variability and analyzed whether recent disturbance episodes around the globe were consistently driven by climate, and if human influence modulates patterns of forest disturbance. We combined remote sensing data on recent (2001–2014) disturbances with in-depth local information for 50 protected landscapes and their surroundings across the temperate biome. Disturbance patterns are highly variable, and shaped by variation in disturbance agents and traits of prevailing tree species. However, high disturbance activity is consistently linked to warmer and …


Using Transboundary Wildfire Exposure Assessments To Improve Fire Management Programs: A Case Study In Greece, Palaiologos Palaiologou, Alan A. Ager, Max Nielsen-Pincus, Cody Evers, Kostas Kalabokidis Jul 2018

Using Transboundary Wildfire Exposure Assessments To Improve Fire Management Programs: A Case Study In Greece, Palaiologos Palaiologou, Alan A. Ager, Max Nielsen-Pincus, Cody Evers, Kostas Kalabokidis

Environmental Science and Management Faculty Publications and Presentations

Numerous catastrophic wildfires in Greece have demonstrated that relying on fire suppression as the primary risk-management strategy is inadequate and that existing wildfire-risk governance needs to be re-examined. In this research, we used simulation modelling to assess the spatial scale of wildfire exposure to communities and cultural monuments in Chalkidiki, Greece. The study area typifies many areas in Greece in terms of fire regimes, ownership patterns and fire-risk mitigation. Fire-transmission networks were built to quantify connectivity among land tenures and populated places. We found that agricultural and unmanaged wildlands are key land categories that transmit fire exposure to other land …


The Economic Contribution Of Stewardship Contracting: Two Case Studies From The Mount Hood National Forest, Jean M. Daniels, Max Nielsen-Pincus, Mike Paruszkiewicz, Nathan Poage May 2018

The Economic Contribution Of Stewardship Contracting: Two Case Studies From The Mount Hood National Forest, Jean M. Daniels, Max Nielsen-Pincus, Mike Paruszkiewicz, Nathan Poage

Environmental Science and Management Faculty Publications and Presentations

We conducted an economic analysis of two case study stewardship contracts on the Mount Hood National Forest in western Oregon. Stewardship contracting has been embraced by some federal managers to achieve restoration goals while providing economic benefits to local communities. Little is known about economic contributions from stewardship contracts, including how they compare against Secure Rural Schools funding or the century-old payments to counties revenue sharing system. Using expenditure data from sale purchasers, contractors, and fiscal agents, we developed methodology to track spending and used IMPLAN software to estimate economic contributions and multipliers. Results showed that (1) commercial thinning, service …


Assessing Transboundary Wildfire Exposure In The Southwestern United States, Alan A. Ager, Palaiologos Palaiologou, Cody Evers, Michelle A. Day, Ana M.G. Barros Apr 2018

Assessing Transboundary Wildfire Exposure In The Southwestern United States, Alan A. Ager, Palaiologos Palaiologou, Cody Evers, Michelle A. Day, Ana M.G. Barros

Environmental Science and Management Faculty Publications and Presentations

We assessed transboundary wildfire exposure among federal, state, and private lands and 447 communities in the state of Arizona, southwestern United States. The study quantified the relative magnitude of transboundary (incoming, outgoing) versus nontransboundary (i.e., self-burning) wildfire exposure based on land tenure or community of the simulated ignition and the resulting fire perimeter. We developed and described several new metrics to quantify and map transboundary exposure. We found that incoming transboundary fire accounted for 37% of the total area burned on large parcels of federal and state lands, whereas 63% of the area burned was burned by ignitions within the …


Assessing The Effects Of Climate Change And Fuel Treatments On Forest Dynamics And Wildfire In Dry Mixed-Conifer Forests Of The Inland West: Linking Landscape And Social Perspectives, Brooke Alyce Cassell Mar 2018

Assessing The Effects Of Climate Change And Fuel Treatments On Forest Dynamics And Wildfire In Dry Mixed-Conifer Forests Of The Inland West: Linking Landscape And Social Perspectives, Brooke Alyce Cassell

Dissertations and Theses

Over the past century in the western United States, warming has produced larger and more severe wildfires than previously recorded. General circulation models and their ensembles project continued increases in temperature and the proportion of precipitation falling as rain. Warmer and wetter conditions may change forest successional trajectories by modifying rates of vegetation establishment, competition, growth, reproduction, and mortality. Many questions remain regarding how these changes will occur across landscapes and how disturbances, such as wildfire, may interact with changes to climate and vegetation. Forest management is used to proactively modify forest structure and composition to improve fire resilience. Yet, …


Effects Of Variable Density Thinning On Spatial Patterns Of Overstory Trees In Mt. Hood National Forest, Emma Huston Jan 2018

Effects Of Variable Density Thinning On Spatial Patterns Of Overstory Trees In Mt. Hood National Forest, Emma Huston

Environmental Science and Management Professional Master's Project Reports

Variable density thinning (VDT) is a method of restoration thinning that attempts to increase ecosystem resilience and spatial heterogeneity in forest stands to more closely resemble mosaic-like patterns characteristic of late-successional forests, which consist of clusters of multiple trees, individual trees, and gaps. This study examines the spatial patterning of overstory trees resulting from VDT of conifer forests in Mt. Hood National Forest in the western Cascade Mountains and compares these patterns with reference conditions. Stem maps were created from field surveys of study plots within one mature stand and six thinned stands designated as Late-Successional Reserve (LSR) with varying …