Fire

British Columbia's applied fire research is advancing our understanding of fire impacts and ecosystem responses in the province's diverse forests. 

The implications of post-wildfire landscapes and resulting geohazard risk such as landslides, as well as work that seeks to build in resilience to BCs forests through considering fire as part of forest management are examples of this. Current research focuses on adapting forest management practices to these changing climate conditions, adapting tree-stock types to grow in post-fire soils and exploring innovative approaches to management and timber supply issues such as prescribed burning and strategic fuel reduction.

Post-wildfire Natural Hazards Risk Analysis in British Columbia - LMH69

Following a wildfire, the chances of soil erosion, floods, and landslides increase, and resultant damage downslope and downstream of the area burned may be catastrophic. This handbook describes the process of assessing change following wildfire, together with an evaluation of downslope and downstream risks to life, property, and infrastructure, or “elements at risk.” The process described will help professionals adapt their knowledge and experience to post-wildfire natural hazard risk analyses. The minimum set of background data, field reviews, and other information that should be included in all assessments is described. Assessing and mapping soil burn severity is the important first step in any analysis, forming the basis for subsequent soil erosion, hydrology, and geomorphic hazard assessments. The last step, determination of partial risk for each hazard and element, is broadly described. Five British Columbia fire case studies illustrate the application of the procedure. Risk treatment options are discussed; emphasis is placed on upgrading of road drainage structures and slope treatments, especially mulching.

Vegetation Response, Fire Effects, and Tree Growth after Slashburning in the Engelmann Spruce–Subalpine Fir Zone - TR37

Fire effects, and vegetation and seedling response to burning, were monitored for 10 years after slashburning on the Goat River site. A fire weather station and gravimetric sampling were used to determine weather codes and indices and forest floor moisture content. Fuel loading, fuel consumption, and burn severity were ascertained using fuel assessment triangles and permanent plots. Changes in floristic composition and structure (cover and height) were documented along with survival and growth of planted hybrid white spruce seedlings.

The patchy burn was of fairly low severity, with little mineral soil exposure or large fuel consumption. When measured forest floor moisture content was used as an input, duff and fuel consumption as well as mineral soil exposure were less than predicted by the Prescribed Fire Predictor. After the site was logged and burned, the vegetation structure at ground level shifted from a community dominated by bryophytes and small herbs to a young conifer forest with mosses, taller herbs, and shrubs. After 10 years, bryophyte cover was 77%, which was comparable to pre-burn levels (82%), herb cover was 14% or approximately one-half of pre-burn levels (24%), and shrub cover was 12% or double the pre-burn levels (6.5%). Shrubs were the tallest life form after the site was logged, but they had not regained pre-burn heights 10 years after burning. Although some of the original forest species were lost, a number of new species established from seed banks and off-plot sources.

Fire Effects and Post-burn Vegetation Development in the Sub-Boreal Spruce Zone - TR33

The purpose of this study was to document fire effects and subsequent changes in vascular species composition and structure after a slashburn. Survival and growth of planted hybrid spruce seedlings were also monitored. The study site is a clearcut at Windy Point in the Mackenzie Forest District in the Sub-Boreal Spruce zone in northern British Columbia. Six permanent plots were established prior to burning and monitored for 10 years after the fire. Fire weather codes and indices were calculated, fuel loading and consumption were determined, and burn severity was measured at three fuel assessment triangles and in the vegetation plots. The slashburn was of low to moderate severity and consumed 22% of the forest floor. Impacts were considerably less than those forecasted using the Prescribed Fire Predictor in conjunction with the Canadian Forest Fire Weather Index System, likely because the cutblock forest floor was wetter than predicted.  Ten years after burning, the site was dominated by young planted hybrid white spruce, shrubs, and herbs. Most of the original shrub and herb species are well adapted to burning and re-established after the fire by resprouting.

Large-scale Erosion and Flooding after Wildfires - TR30

Large-scale erosion and flooding after severe wildfires are common, normal occurrences in mountainous or hilly terrain. These events include debris flows, mudflows, mudslides, gully erosion, landslides, and debris floods. When such phenomena occur away from human activity, they go largely unnoticed, even when they may be locally significant. However, in interface locations, these events attract media attention because they can be catastrophic, destroying infrastructure such as roads and water supply systems, property, and lives. In some parts of the Southern Interior, these events seemed more pronounced after the 2003 wildfires. By the end of 2004, at least five major soil erosion and/or flooding events related to the 2003 fires had occurred. Recent research in the Interior has shown that, since glaciation, similar large-scale erosion and flooding have repeatedly occurred after wildfires. These events significantly shape the post-glacial Interior landscape, with one result being large deposits on alluvial and colluvial fans.

Succession after Slashburning in an Engelmann Spruce–Subalpine Fir Subzone Variant - TR28

This study was undertaken to determine the successional development after a slashburn of known severity on an Engelmann Spruce–Subalpine Fir (ESSF) biogeoclimatic zone site. Herbaceous and shrubby vegetation composition, cover, and height were monitored along with the growth of planted spruce seedlings for 11 years in 30 permanent sample plots. Fire effects were determined using depth-of-burn pins to measure forest floor consumption and fuel assessment triangles to measure fuel loading and consumption following a microplot approach. Fire weather conditions were determined using standard methods outlined in the Canadian Forest Fire Weather Index System. The fire on this site was quite severe and consumed 52% of the organic layer. The consumption of such a high percentage of the forest floor favoured establishment of invasive species. Regrowth of some native forest species was quite slow. This may be attributable to the severity of the conditions on the site after burning (e.g., poorer in nutrients, more extreme temperature fluctuations). Planted conifer establishment was quite successful and growth fairly rapid; this may have restricted the growth of understorey species. 

Vegetation Development and Fire Effects at the Walker Creek Site Comparison of Forest Floor and Mineral Soil Plots - TR26

The objective of this study was to quantify the response of vegetation on a cutblock in the SBSvk subzone under known burning conditions by monitoring fire weather, fire effects, and vegetation development. Vegetation succession on forest floor and mineral soil (skid roads) permanent sample plots was monitored. Standard fire weather information was collected along with fuel loading and forest floor layer depths (i.e., litter and duff 2 layer depth) before and after burning to characterize the fire effects and burning conditions. Methods outlined in the Canadian Forest Fire Weather Index System (CFFWIS) were used. The observed fire effects (duff and woody fuel consumption and mineral soil exposure) were compared to those predicted when the Prescribed Fire Predictor was used in conjunction with the CFFWIS predictions of Duff Moisture Code (DMC) and duff moisture level (DML) derived from sampling the duff at the time of burning. Cover and height of vascular species was monitored in 147 permanent sampling plots for 10 years. Mode of establishment of species was determined where possible.

The equation devised by Lawson, Dalrymple, and Hawkes in 1997 for pine/spruce-feathermoss sites in the Yukon approximated the DMC and DML relationship found on this site. The DML was accurately predicted by the CFFWIS. Actual duff consumption and mineral soil exposure were significantly lower than predicted and woody fuel consumption was greater than predicted. These discrepancies reflect the limitations of the Prescribed Fire Predictor on this site under the conditions in which the burn was done. There were 32 vascular plant species on the forest floor plots prior to burning. By the tenth year after burning, there were 74 species. There were 13 vascular plant species in the mineral soil plots before burning and 52 by year 10. Many herb and shrub species established on the mineral soil plots in the first year after burning.

Field Handbook for Prescribed Fire Assessments in British Columbia - LMH11

Prescribed fire is an important site treatment in British Columbia for forest, range, and wildlife management. In 1985, over 135 000 ha in the province were treated with it. This Land Management Handbook contains standard methods of prescribed fire research assessments for logging slash fuels in British Columbia, and describes the procedures required for making pre-burn assessments, observations during the fire, and post-burn assessments. At this time, all procedures included are oriented toward documenting and evaluating broadcast prescribed fire. Eventually, these may be modified and other -procedures added, such as those for evaluating seedling response, different types of prescribed fire (e.g., underburning), and use of fire for purposes other than silviculture (e.g., range and wildlife). This handbook is designed solely for voluntary operational assessments. It is intended to document the prescribed fire treatment and to assess the success or failure of specific fire prescriptions. Ultimately it may lead to the accumulation of a data base for a computerized prescribed fire management information system. The fate of an information system will depend on the successful application of the techniques described in this handbook and on the related research trials and experimentation.