Storage and fluxes of carbon in coarse woody debris of Fagus sylvatica L.

Quelle: Forstarchiv 79: 5, 164-171 (2008)
Autor(en): Müller-Using S, Bartsch N

Abstract: C storage and CO2 emission of coarse woody debris (CWD, diameter > 10 cm) were studied in a 160 year old European beech (Fagus sylvatica L.) stand in the Solling hills in Germany. A chronosequence was used for analyzing long term changes of C content in CWD. During the observed decomposition period of 28 years, concentration of carbon (C) in CWD changed only slightly. CO2 emission rates of 21 log sections of different decay stages were fortnightly measured for 24 months. The 2-year time series showed pronounced seasonal dynamics. Depending on the residence time of the logs, summer emission rates ranged between 0.9 and 4.8 g m-3 h-1. The decomposition process began slowly. In decay class 2 microbial activity was clearly at its peak. A second peak occurred during the final decomposition phase (decay class 4). Based on the current store of CWD, the CO2 emission rate was 0.55 Mg CO2-C ha-1 a-1. More than half of the emission originated from logs with a residence time of two to four years. Emission rates from the soil of the study area were up to six times higher. The CO2 emission is only one aspect of the reduction of the C storage of woody debris. Despite its minor role for the total C storage of the stand, a near to nature supply of woody debris increases the CO2 emission of the forest floor considerably.

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