Bracken fern-dominated plant communities exist in a mosaic with mid-elevation grand fir forests in the mountains of northern Idaho. Although some ‘natural' bracken glades pre-date European settlement and are as old as 6700 years, ‘artificial' bracken glades have formed as a result of canopy removal over the past several decades. Following canopy removal, bracken fern quickly invades and little to no regeneration of woody species occurs. We studied six natural and artificial bracken glades to examine the effect of bracken fern on properties of Andisols, the dominant soils of the region. Bracken fern glades contain an average of 2000 g/m2 of belowground rhizome biomass, almost twice the belowground biomass of the adjacent grand fir forest. This preferential allocation of biomass belowground drives the development of nonallophanic properties in soils of bracken fern glades. Increases in acidity, organically bound forms of Al, and KCl-extractable Al are observed relative to the forest soils. These changes become more pronounced with increasing bracken fern glade age, and are likely related to the observed difficulties with timber regeneration.
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