Soil acidity affects fine root turnover of European beech

Abstract

The impact of soil chemical parameters (pH and base saturation) and soil depth on fine root dynamics in six acidic European beech (Fagus sylvatica L.) stands with low soil base saturation was examined. The results were compared with published data from other European forests. Fine roots were sampled by sequential coring down to 1 m depth. Production, mortality, turnover and estimated age were calculated, and the ages of fine roots from two stands were measured by radiocarbon. In all stands, fine root biomass, necromass, production and mortality decreased significantly with soil depth. No relationships were observed between any of the soil chemical parameters and the fine root biomass, necromass, production and mortality. A significant negative correlation was found between soil pH and fine root turnover when our data were combined with the published data. The ages of fine roots estimated with sequential coring ranged from 0.9 to 2.9 years, and with radiocarbon from 3 to 26 years. These divergent results indicate the occurrence of two different fine root pools.

Keywords:

• Base saturation (BS)
• Fagus sylvatica
• fine root age
• fine root turnover
• radiocarbon

Acknowledgements

We thank Roger Köchli and Sven Knollmann for helping with the fieldwork, Lorenz Walthert und Matthias Dobbertin for support in data acquisition, Anne Kress and Matthias Saurer from the PSI and Tina Endrulat from WSL for helping with the cellulose extraction, the ETH/PSI AMS facilities for measuring the Δ14C data, the group of Emmanuel Frossard for constructive discussions, and Silvia Dingwall for correcting and improving our English. This study was financed by the VELUX Foundation.