Forest topsoil organic carbon content in Southwest Bohemiaregion

The aim of this study was to evaluate organic carbon content (SOC) in the surface layers of forest soils in the two Natural Forest Regions situated in Southwest Bohemia, namely Západočeská pahorkatina (NFR 6) and Český les (NFR 11). The study is based upon on two consecutive soil sampling campaigns during autumn 2003 and 2004. While the sampling of 2003 was inadequate to estimate bulk density, the consecutive campaign used a defined sample volume to permit an estimation of bulk density and quantification of soil organic carbon (SOC) for soil organic layers and the upper mineral horizon. The total sampling depth was 30 cm including both organic and mineral layer. SOC of organic horizon was on average 1.99 kg C/m2. It differed by stand site type ranging from 0.70 to 3.04 kg C/m2. The organic layer SOC was smallest under beech (1.03 kg C/m2), whereas it was higher under pine (2.19 kg C/m2) and spruce (2.09 kg C/m2). SOC in the mineral layer was in average 7.28 kg C/m2. SOC differed significantly by the major tree species and reached 10.6; 5.67 and 7.5 kg C/m2 for beech, pine and spruce sites, respectively. The average SOC for the total soil layer (0-30 cm) reached 9.33 kg C/m2. The methodological aspects of regional estimation of SOC and the potential of utilization of the national forest inventory program are also discussed.