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Regeneration of lodgepole pine after wildfire in mountain pine beetle-killed stands in north-central British Columbia

Posted on:2009-03-12Degree:M.ScType:Thesis
University:University of Northern British Columbia (Canada)Candidate:Scholefield, Scott RFull Text:PDF
The objectives of this thesis were to (i) characterize lodgepole pine regeneration and related micro-site conditions associated with wildfire, and (ii) identify limitations for germination, survival and recruitment of natural and artificial regeneration in relation to site moisture, fire severity, and vegetative competition. The germination, survival and recruitment of lodgepole pine seedlings over two growing seasons were compared on 18 disturbance plots (replicated three times) on several treatments including three fire severity classes (high, moderate, low), two moisture regimes (dry and wet), two seed provenances (wild and improved), and two seedbed types (disturbed and undisturbed). Results showed that natural regeneration was highest on wet sites and seedling density increased with declining fire severity. On dry sites, new germinants were rare and limited by micro-site conditions associated with high and moderate fire severity with highest germination rates experienced on low fire severity. Seed provenance did not influence germination and survival rates.;In this thesis, we were able to document that: (a) site conditions following MPB and wildfire limited germination, survival, and recruitment rates; (b) the extent of vegetation establishment was dependent upon fire severity and wetter sites provided more favourable conditions for plant re-establishment than dry sites; (c) the density of natural regeneration was highest in stands which experienced less severe fire severity effects; (d) a spring pulse of germination occurred in both years in seeded plots and germination continued throughout both growing seasons on all sites; (e) micro-site at the germinant level is important for early establishment of lodgepole pine; (f) there was no difference in early survival rates of wild and improved Class-A seed; (g) using ordered logistic regression to estimate the probability of survival, the model found that the odds of wild seeds surviving were slightly lower, and survival rates of planted seedlings indicated that growth limitations were higher in burned stands than in unburned stands.;Lodgepole pine forests on wet sites may be better able to respond to successive natural disturbances of MPB infestation and wildfire, having implications for prioritizing the forest management response. Regeneration assessments indicated that sufficient levels of natural lodgepole pine regeneration exists, not requiring immediate management intervention (i.e. under planting). Where natural conifer regeneration was limited on low productivity sites, it is recommended that stands be allowed to develop as mixed stands. Salvage in such stands may compound the disturbance effects of MPB and wildfire.
Keywords/Search Tags:Fire, Lodgepole pine, Regeneration, Stands, MPB, Conditions
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