Soil respiration rates and in natural beech forest (Fagus sylvaticaL.) in relation to stand structure

Soil respiration rates were studied as a function of soil type, texture and light intensity at five selected natural beech forest stands with contrasting geology: stands on silicate bedrock at Kladje and Bricka in Pohorje, a stand on quartz sandstone at Vrhovo and two stands on a carbonate bedrock in the Karstic-Dinaric area in Kocevski Rog, Snežna jama and Rajhenav, Slovenia, during the growing season in 2005–2006. Soil respiration exhibited pronounced seasonal and spatial variations in the studied forest ecosystem plots. The CO2 flux rates ranged from minimum averages of 2.3 μmol CO2 m−2 s−1 (winter) to maximum averages of about 7 μmol CO2 m−2 s−1 (summer) at all the investigated locations. An empirical model describing the relationship between soil respiration and soil temperature predicted seasonal variations in soil respiration reasonably well during 2006. Nevertheless, there were also some indications that soil moisture in relation to soil texture could influence the soil CO2 efflux rates in both sa...