Aspen Bibliography

Humus forms of trembling aspen ecosystems in northeastern British Columbia

Document Type

Article

Journal/Book Title/Conference

Forest Ecology and Management

Volume

105

Issue

1-3

First Page

241

Last Page

250

Publication Date

1998

Abstract

For humus forms are one of the less known features of trembling aspen ecosystems, we studied them in 18 stands located across a range of soil moisture and nutrient regimes in the Boreal Black and White Spruce of northeastern British Columbia. The majority of study on humus forms featured loose Fz (zoogeneous) horizons, overlying thicker, compact-matted Fm (mycogeneous) horizons. Fine roots were concentrated at the lower boundary of Fm horizons. The occurrence of both Fz and Fa horizons implied the presence of two contrasting decomposition processes: one dominated by soil fauna (Fz) and the other dominated by soil fungi (Fm). We consider these humus forms to represent an intergrade between Mors and Moders, as supported by the results of chemical analysis. However, the Fz–Fm profile did not fit any taxon of the Mor or the Moder order in the existing humus form classification, and by default these humus forms had to be considered Hemimors. We suggest that a higher temperature near the ground surface and aspen litter are responsible for the development of the upper Fz horizon, and a lower temperature and dense root mat are responsible for the development of the lower Fm horizon. Considering this unique and persistent pattern across a range of aspen ecosystems, we proposed a new group of the Moder order—Lamimoder.

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