Skip to Main Content
Chemical and mineralogical conversion of Andisols following invasion by bracken fernAuthor(s): J. L. Johnson-Maynard; P. A. McDaniel; D. E. Ferguson; A. L. Falen
Source: Soil Science Society of America Journal. 61(2): 549-555.
Publication Series: Miscellaneous Publication
PDF: View PDF (586.47 KB)
DescriptionAndisols support ≈ 200 000 ha of mid-elevation grand fir (Abies grandis [Dougl. ex D.Don] Lindl.) forests in the Pacific Northwest region that are characterized by little or no natural conifer regeneration following removal of the forest canopy. Previous work suggests that the properties of these Andisols have been altered as a result of the establishment of successional communities dominated by bracken fern (Pteridium aquilinum [L.] Kuhn) in deforested areas. In this study, we compared soil properties in a 30-yr-old bracken fern site (clear-cut in 1965), a natural bracken fern site that is estimated to be centuries old, and an adjacent undisturbed forest in the Clearwater National Forest of northern Idaho. Results indicate that changes in chemical properties have accompanied establishment of successional communities. Mean weighted pH within the ash cap of the 30-yr-old bracken fern site (4.6) is significantly lower than that of the undisturbed forest (5.2). Mean values for AI saturation range from 27% in the undisturbed forest to 52% in the 30-yr-old bracken fern site; organic C is also lower in the undisturbed forest (37 g/kg) than in the 30-yr-old bracken fern site (54 g/kg). The dominant secondary mineralogical component of soils of the undisturbed forest is inorganic, short-range-order AI-Fe minerals, while metal-humus complexes are dominant in the bracken-fern-influenced soils. Data indicate that bracken fern successional communities are responsible for a shift from allophanic to nonallophanic properties in these soils, probably due to increased levels of soil organic C associated with bracken fern and a subsequent increase in formation of AI-humus complexes. Furthermore, such a mineralogical shift may contribute to the observed problems with conifer regeneration.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationJohnson-Maynard, J. L.; McDaniel, P. A.; Ferguson, D. E.; Falen, A. L. 1997. Chemical and mineralogical conversion of Andisols following invasion by bracken fern. Soil Science Society of America Journal. 61(2): 549-555.
KeywordsAndisols, bracken fern, Pteridium aquilinum, grand fir, Abies grandis
- Reforestation trials and secondary succession with three levels of overstory shade in the Grand Fir Mosaic ecosystem
- The Grand Fir Mosaic Ecosystem -- History and Management Impacts
- Supplemental treatments to aid planted Douglas-fir in dense bracken fern
XML: View XML