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. Some shrubs (i.e., Rubus parviflorus, Rubus idaeus, Ribes laxiflorum, Ribes lacustre, and Sambucus racemosa) and herbs (i.e., Geranium bicknellii and Corydalis sempervirens) established by germination from long-lived seed banks immediately after the fire. A few of the original herb and bryophyte species, including Rubus pedatus, had not reappeared by year 10. New species, such as Salix sp. and Epilobium angustifolium, established by seeding-in from off-site sources. Species including Ribes laxiflorum and Rubus idaeus increased in cover and frequency and then declined; others such as Alnus tenuifolia and Gymnocarpium dryopteris gradually increased in abundance over time and others decreased steadily. Establishment of new species continued for many years after the site was burned.
