Soil respiration at forest sites in Saxony (Central Europe)

Abstract

Soil respiration is the second largest CO₂-exchange process between terrestrial ecosystems and the atmosphere. Yet, high-quality experimental data are still in demand. During the vegetation period of 2013 we measured soil and ecosystem respiration with a closed dynamic flux chamber at six Saxon ICP-Forests Level II monitoring sites, representative for Central Europe. Each site comprises a closed canopy (UC) and an open field (OF) plot. Apart from CO₂ fluxes, meteorological parameters were recorded, assuring that the chosen measurement period was representative for longer time frames. Additional soil samples delivered current chemical conditions. Carbon dioxide fluxes at the open field plots were 30–250 % higher than under canopy—due to different plant cover. Under canopy, 2.7–5.8 µmol CO₂ m⁻² s⁻¹ were determined (median 3.5 µmol CO₂ m⁻² s⁻¹), while the open field showed a range of 3.2–15.5 µmol CO₂ m⁻² s⁻¹ (median 7.6 µmol CO₂ m⁻² s⁻¹). The key drivers for soil metabolism, soil temperature, humidity and nutrient budget, showed distinct plot and site differences. Surmising that the determined fluxes are representative for Saxony and its temperate forests, and calculating with winter half year data from the literature, it can be deduced that 3.85 Mt C of carbon would be released annually from Saxon forest soils.