Slashburning on fire-sensitive sites reduced the abundance of existing conifers and shrubs in proportion to burn intensity. Speed of regrowth of surviving species, and establishment of new plant species was variable in the 6 years following treatment. Forb cover increased rapidly, but began to decline by year six. Cover values did not peak simultaneously for all species. For example, fireweed cover peaked within 2 years, while cover of hairy cat's-ear was still increasing 6 years after burning. Deciduous shrub cover was severely reduced by all levels of burning, and did not regain preburn levels within 6 years of treatment. Over the same time period, shrub cover more than doubled on the unburned control area. Existing conifers were killed by burning. Planted conifers increased in cover more rapidly on the high-intensity burn sites. Competition with shrubs probably slowed conifer development on the light burn sites. Much evergreen shrub cover was removed by treatment, but fire also stimulated sprouting and encouraged rapid regrowth. On the light burn treatment areas, cover exceeded preburn levels within 2 years of burning. Effective control of evergreen shrubs was only achieved on the most severe burn sites.
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Updated November 25, 2008