The Mt. Horetzky prescribed burn project was initiated in 2015 as a collaborative effort between PIR (West Fraser), Lake Babine Nation, BC Wildfire Service, SERNbc and several other partners. The study is located in Wit’at territory in the Nilkitkwa valley, 38 km north of Fort Babine. The Bulkley Valley Research Centre (BVRC) was contracted to carry out ecological monitoring of the proposed slashburn to assess the ecological objectives of enhancing edible berry production and grizzly bear forage are met. BVRC also assisted in training several members of the Lake Babine Nation at Fort Babine in ecological monitoring. Another goal for the project was to integrate scientific data with traditional ecological knowledge regarding prescribed burning for the enhancement of edible berries and wildlife habitat.
This establishment report outlines our study plan and describes methods and results for 2015. As the prescribed burn did not take place in fall 2015 due to poor weather, this report describes pre-burn activities and results only. Our literature review and prior experience monitoring slashburns indicated no clear scientific evidence that broadcast burning of logging slash followed by tree planting will necessarily enhance berries and grizzly forage. To more adequately test this hypothesis, we used a Tier III (intensive) monitoring approach. We modified SERNbc’s draft Tier II prescribed burn monitoring protocol by adding 5 unburned control transects and a higher density of treatment transects (20 in total) to adequately represent the three dominant SBSmc2 site series, but with fewer transects per sample plot (2 or 1 rather than 4 per plot). We sampled berries and also quantified pre-burn woody fuels of all sizes. We installed depth-of-burn pins in the forest floor to more closely monitor fuel consumption and burn severity and to allow these variables to be correlated with fire weather indices. Two transects were located in adjacent unlogged forest. In total we established 22 sample plots comprising 27 transects.
We examined the data for pre-burn differences in woody fuels, vegetation and grizzly forage species and berry production by treatment (unlogged; no burn control; proposed burn area) and by SBSmc2 site series (Oakfern; Devil’s-club; Horsetail). Fuel loads were high (512 + 60m3/ha) and did not differ significantly among treatments or site series due to within-block variability. Shrub and herb layers were sparse due to 2014/15 logging, but most old-growth understory species were present. False azalea and highbush blueberry, both fire-sensitive species, were the dominant shrubs. We predict a shift to more fire-tolerant species such as black huckleberry, thimbleberry and red raspberry if the burn is successful. The Horsetail site series had the greatest diversity of herbs including valuable grizzly spring forage species such as horsetails and lady fern.
We strongly recommend that the site be cluster-planted to create semi-permanent gaps that will delay the shading-out of valuable forage plants and berries.
Two natural resource technicians from Fort Babine assisted the BVRC crew for 4-6 days each. They provided local ecological knowledge and received training in prescribed burn monitoring. Both participants had a wealth of field experience and ably assisted our crew. Although we missed out on a few days of post-burn monitoring that would have greatly added to the shared learning experience, the pre-burn collaboration, from our perspective, was very successful.