Prescribed burns are employed in the southern boreal forest of northwest Ontario, Canada, as a method of re-instating fire in this fire-dependent landscape. They are also used to manage fuel loads associated with tree mortality from defoliating insects and from blow-downs, as well as in-site preparation following harvest. The natural fire season in boreal Canada typically runs from April through September and is most often characterized by stand replacing fires. However, prescribed burns in northwestern Ontario are mostly scheduled for October when fire crews and equipment are available and fire hazard is reduced. In this study, three recent fires: a spring prescribed natural fire, a summer wildfire, and a fall prescribed burn were examined to assess the effect of season on post-fire legacies in red-pine mixedwood stands in Quetico Provincial Park, northwestern Ontario. Legacies were assessed by tree, shrub and herb species composition, and by measurements of structure such as litter depth, basal areas of live trees and coarse woody debris. Tree species diversity was nearly identical. Post-fire stand structure varied widely between the different sites. The spring treatment experienced the least mortality of trees (10% of basal area dead); the summer treatment had the highest mortality (100%); and the fall prescribed burn was intermediate with 49% dead. The effect of the fall burn on the forest was probably more intense than that of a comparable natural fall fire because of the way in which it was managed, thus partly compensating for the late season. <br /><br /> This research suggests that all fires are not equal. Different post-fire structure will have lasting ecological implications such as varying edge to interior ratios, and forest habitats. From a policy perspective this is important because maintaining ecological processes including fire is mandated for some provincial parks. In addition, the new Fire Policy for Ontario has established targets to limit wildfires, and permit ecologically renewing fires, without recognition of the variability of the effects of fire or fire legacies.

Prescribed burns are employed in the southern boreal forest of northwest Ontario, Canada, as a method of re-instating fire in this fire-dependent landscape. They are also used to manage fuel loads associated with tree mortality from defoliating insects and from blow-downs, as well as in-site preparation following harvest. The natural fire season in boreal Canada typically runs from April through September and is most often characterized by stand replacing fires. However, prescribed burns in northwestern Ontario are mostly scheduled for October when fire crews and equipment are available and fire hazard is reduced. In this study, three recent fires: a spring prescribed natural fire, a summer wildfire, and a fall prescribed burn were examined to assess the effect of season on post-fire legacies in red-pine mixedwood stands in Quetico Provincial Park, northwestern Ontario. Legacies were assessed by tree, shrub and herb species composition, and by measurements of structure such as litter depth, basal areas of live trees and coarse woody debris. Tree species diversity was nearly identical. Post-fire stand structure varied widely between the different sites. The spring treatment experienced the least mortality of trees (10% of basal area dead); the summer treatment had the highest mortality (100%); and the fall prescribed burn was intermediate with 49% dead. The effect of the fall burn on the forest was probably more intense than that of a comparable natural fall fire because of the way in which it was managed, thus partly compensating for the late season. <br /><br /> This research suggests that all fires are not equal. Different post-fire structure will have lasting ecological implications such as varying edge to interior ratios, and forest habitats. From a policy perspective this is important because maintaining ecological processes including fire is mandated for some provincial parks. In addition, the new Fire Policy for Ontario has established targets to limit wildfires, and permit ecologically renewing fires, without recognition of the variability of the effects of fire or fire legacies.

An investigation of the petrology and chemistry of two groups of mafic-rich intrusions from the Lac des Mille Lacs area was carried out. The Quetico group consists of hornblende-rich ultramafic to mafic rocks; the Shebandowan group consists of serpentinized ultramafic rocks and metagabbro. A spectrographic method was employed to quantitatively determine Al2O3, CaO, Co, Cr, Cu, Mn, Ni, Ti, V and Zr in the rocks. This, and other chemical data, indicate that these two spatially related groups, although mineralogically distinct, have similar chemical features, and have apparently crystallized from compositionally similar magmas under different water vapour pressures. Their similarities to ultramafic rocks from other areas provide some implications regarding ultramafic rock types of orogenic areas. / Thesis / Master of Science (MSc)

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Fire is the primary natural disturbance vital to the ecological integrity of Quetico Provincial Park, Ontario, Canada. A new provincial park planning process (i.e., Class Environmental Assessment) has required the review of Quetico’s Fire Management Plan. To support this review, large and severe (stand-replacing) Quetico fires were studied using 1966 Ontario Ministry of Natural Resources (OMNR) forest resource inventory (FRI) mapping. A Geographic Information Systems (GIS) database of the FRI was created and updated with the OMNR digital fire atlas. This database was used as a time-since-fire and fire interval dataset to estimate fire frequency. It also served to archive the 1966 FRI for the largest protected area in the transition between the Boreal and Great Lakes-St. Lawrence forest regions. Non-parametric (Kaplan-Meier) survival analysis was used to estimate survival functions and mean fire intervals (i.e., the expected time between two consecutive stand-replacing fires for any location within the Park). Previous studies that have used Kaplan-Meier survival analysis methods have based fire frequency estimates solely on time-since-fire data. However, time-since-fire data cannot be equated with fire interval data when using non-parametric methods. At least one fire interval is required to obtain reliable results. The mean fire interval for the entire 475,782 ha Park between the years 1668 and 2007 was 230 years. Performing the analysis on various geographic and temporal partitions revealed fire frequency spatial and temporal variability. A constant (independent of time-since-fire) probability of burning was not observed for Quetico which is contrary to accepted conjecture for northwestern Ontario boreal/mixed-wood forests. A current fire cycle was also estimated for the Park (342 years) using the digital fire atlas. The results suggested that use of historical static fire frequency estimates as fire management prescriptions may not be justified given considerable fire frequency temporal variability. The observed fire frequency spatial variability suggests that studies should be undertaken at coarser scales than is the norm to characterise the regions fire regime in support of landscape level fire management planning.

Fire is the primary natural disturbance vital to the ecological integrity of Quetico Provincial Park, Ontario, Canada. A new provincial park planning process (i.e., Class Environmental Assessment) has required the review of Quetico’s Fire Management Plan. To support this review, large and severe (stand-replacing) Quetico fires were studied using 1966 Ontario Ministry of Natural Resources (OMNR) forest resource inventory (FRI) mapping. A Geographic Information Systems (GIS) database of the FRI was created and updated with the OMNR digital fire atlas. This database was used as a time-since-fire and fire interval dataset to estimate fire frequency. It also served to archive the 1966 FRI for the largest protected area in the transition between the Boreal and Great Lakes-St. Lawrence forest regions. Non-parametric (Kaplan-Meier) survival analysis was used to estimate survival functions and mean fire intervals (i.e., the expected time between two consecutive stand-replacing fires for any location within the Park). Previous studies that have used Kaplan-Meier survival analysis methods have based fire frequency estimates solely on time-since-fire data. However, time-since-fire data cannot be equated with fire interval data when using non-parametric methods. At least one fire interval is required to obtain reliable results. The mean fire interval for the entire 475,782 ha Park between the years 1668 and 2007 was 230 years. Performing the analysis on various geographic and temporal partitions revealed fire frequency spatial and temporal variability. A constant (independent of time-since-fire) probability of burning was not observed for Quetico which is contrary to accepted conjecture for northwestern Ontario boreal/mixed-wood forests. A current fire cycle was also estimated for the Park (342 years) using the digital fire atlas. The results suggested that use of historical static fire frequency estimates as fire management prescriptions may not be justified given considerable fire frequency temporal variability. The observed fire frequency spatial variability suggests that studies should be undertaken at coarser scales than is the norm to characterise the regions fire regime in support of landscape level fire management planning.