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dc.contributor.advisorHarvey, Brian J
dc.contributor.authorBuonanduci, Michele Susan
dc.date.accessioned2020-02-04T19:30:29Z
dc.date.available2020-02-04T19:30:29Z
dc.date.submitted2019
dc.identifier.otherBuonanduci_washington_0250O_20907.pdf
dc.identifier.urihttp://hdl.handle.net/1773/45269
dc.descriptionThesis (Master's)--University of Washington, 2019
dc.description.abstractOutbreaks of native bark beetles (Curculionidae: Scolytinae) are key natural disturbances that shape the structure and function of conifer forests across the northern hemisphere. While drivers of bark beetle outbreaks have been studied extensively at spatial scales ranging from stands to continents, within-stand processes driving individual tree mortality in an outbreak are less well understood. Here we use a spatially explicit long-term monitoring dataset of lodgepole pine (Pinus contorta var. latifolia) forest impacted by a severe mountain pine beetle (Dendroctonus ponderosae) outbreak to explore interactions among fine-scale drivers of beetle-caused tree mortality. Using a hierarchical Bayesian spatial modeling approach, we evaluated whether and how within-stand neighborhood structure and topographic setting interact with tree size to mediate tree level susceptibility to mountain pine beetle outbreak in the Southern Rocky Mountains (USA). We found evidence that both tree growth rate preceding the outbreak and stand structure around the host tree mediated the effect of tree size. However, we did not find evidence that topographic position within a stand mediated the effect of tree size. Mortality probability increased with pre-outbreak growth rate for small to medium sized trees (~10-25 centimeters diameter), but that same effect could not be detected for larger trees. Conversely, mortality probability increased with greater neighborhood density across tree sizes, with the most pronounced effects for medium to large sized trees (~15-30 centimeters diameter). Within-stand topographic variability was not an important predictor of mortality probability; among stands, however, the driest stand conditions experienced the greatest overall mortality. By explicitly considering how natural within-stand heterogeneity mediates individual tree level susceptibility to mountain pine beetle outbreak, our findings bridge an important gap in understanding multi-scale drivers of disturbance dynamics. Identifying factors influencing individual tree mortality in these systems informs our understanding of both the structural development of forest stands and reciprocal feedbacks between stand structure and outbreak dynamics.
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.rightsnone
dc.subjectconifer forest
dc.subjectdisturbance
dc.subjectlodgepole pine
dc.subjectmountain pine beetle
dc.subjectRocky Mountains
dc.subjectspatial model
dc.subjectEcology
dc.subjectForestry
dc.subjectStatistics
dc.subject.otherQuantitative ecology and resource management
dc.titleModeling individual lodgepole pine mortality from mountain pine beetle outbreak in a spatially explicit framework
dc.typeThesis
dc.embargo.termsOpen Access


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