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|Subke, J-A: Forest Floor CO2 in Temperate Forest Ecosystems. An Investigation of Spatial and Temporal Patterns and Abiotic Controls in Bayreuther Institut für Terrestrische Ökosystemforschung (BITÖK): Bayreuther Forum Ökologie, Selbstverlag, 96, 1-119 (2003)|
The flux from the soil in forest ecosystems represents the main path of assimilated carbon back into the atmosphere. The change of the CO2 efflux dynamics in response to changing environmental conditions is therefore seen as critical for the future role of forest as potential sources or sinks of atmospheric CO2. The aim of this thesis is to investigate and describe mathematically the dependence of the soil CO2 efflux of temperate forest ecosystems on environmental parameters.
The investigation starts with a detailed description of the sampling method and equipment. Since the effect of the soil chamber on the natural soil environment is critical for measurements free of artefacts, special attention is given to chamber tests and data quality routines. Using the thus established open chamber system, an in depth analysis of soil CO2 efflux data from an entire growing season in a mature spruce forest is presented. The identification of the most significant environmental parameters (soil temperature and soil moisture) allowed the calculation of annual CO2 efflux sums, displaying a significant impact of soil moisture conditions. Using eddy correlation in conjunction with the open chamber system, it was possible to further identify the contribution of the ground vegetation to the assimilation flux of the ecosystem at the same site.
Finally, the relative contributions of soil CO2 flux to the total ecosystem respiration flux are investigated for four temperate forest plots in Germany and France.