Determining changes in historical forest fire frequency from a time-since-fire map

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dc.contributor.authorReed, William J.
dc.date.accessioned2010-01-08T22:06:43Z
dc.date.available2010-01-08T22:06:43Z
dc.date.copyright1996en
dc.date.issued2010-01-08T22:06:43Z
dc.description.abstractThe paper deals with methods of identifying change points for historical forest fire frequency (hazard rate) using data from a time-since-fire map and an overdispersed survival model with associated quasi-likelihood function. A method of obtaining an approximate P-value for testing the null hypothesis of no change points (homogeneous hazard), against the alternative of one change point, using the likelihood ratio statistic, is presented. It is based on use of the Poisson clumping heuristic for the maximum of a self-normalized Brownian bridge process. Iterative methods of determining multiple change points (analogous to methods of variable selection in regression) are discussed. Once change points have been identified, confidence intervals for the fire frequency in the intervening epochs can be obtained using likelihood ratio methods. Various procedures are applied to time-since-fire map data for Glacier National Park and backwards elimination found to give the most plausible results. Three of the four change points identified correlate well with established historical processes or events.en
dc.description.sponsorshipNSERC Grant OGP7252en
dc.identifier.urihttp://hdl.handle.net/1828/2057
dc.language.isoenen
dc.relation.ispartofseriesDMS-741-IRen
dc.subjectfire frequency
dc.subjectfire history
dc.subjecttime-since-fire map
dc.subjectquasi likelihood
dc.subjectchange points
dc.subjectselection bias
dc.subjectBrownian bridge
dc.subjectPoisson clumping heuristic
dc.subjectmodel selection
dc.subjectbackwards elimination
dc.subjecttechnical reports (mathematics and statistics)
dc.subject.departmentDepartment of Mathematics and Statistics
dc.titleDetermining changes in historical forest fire frequency from a time-since-fire mapen
dc.typeTechnical Reporten

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