The New European Humus Classification System - an Aid for the Interpretation of Spatio-Temporal Dynamics of Alpine Humus Forms

Wien

2005

Artikel aus einer ZeitschriftUnselbständiges Werk

9627S

200123323

Humus forms may vary both in space and over time. Driving agents for the variation are site conditions, species composition (both plant, faunal and microbial communities) and stand structure (altering soil climate and litter input). Investigations of the interactions between humus morphology and variation of these driving agents may improve the diagnostic value of humus forms for the interpretation of forest ecosystem status and dynamic behaviour. In mountainous regions frequently a high variability of the thickness and other morphological characteristics of organic layers and A-horizons may be found over short distances. Under these conditions it is sometimes impossible to describe a representative humus form for a certain plot or site. The new European humus classification system will account for such situations by treating such short distance variations as associations. Associations may either be a product of an uneven micro-topography and/or spatial variability of stand composition and structure or reflect successional stages of forest ecosystems. Examples for such associations are presented for selected Alpine sites. Humus has to be treated as a dynamic system. In some situations a chronosequence or false time series approach, by investigating different development stages of forest ecosystems, allows for the interpretation of spatial patterns of humus forms as series or time sequences.