Article
Soil carbon stock change in the forests of Denmark between 1990 and 2008
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Soils of the forests in Denmark were sampled in permanent plots in 1990 (t1) and resampled (N=124) in 2007–9 (t2). The soils were classified according to the carbon concentration in the uppermost mineral soil horizon (0–25cm) at t1, and according to subsoil texture and presence or absence of CaCO3 in the subsoil. Soil organic carbon (SOC) stocks in forest floor+mineral soil (0–100cm) at t2 had a median of 15.9kgCm−2 (range 4.1–68.9kgCm−2). There was no detectable overall change in SOC during the 18-year period, but different trends were observed within the subsoil texture classes. SOC stocks decreased with increasing initial SOC content (except calcareous mineral soils), consistently with reports from other inventories of SOC change. Unlike coarse and medium textured soils, fine-textured soils (>10% clay in subsoil) with less than 4.1% C in the 0–25cm layer gained 2.1±1.1kgCm−2 (lsmean and 95% confidence limit) during the 18year period (0.11kgCm−2year−1). With only two observation points in time, SOC changes could not be safely interpreted as true changes for subsets of the data, e.g. distinct soil types. Initially very C rich mineral soils and organic soils (C%>12) on average lost 4 and 7kgCm−2. These C losses from very C rich mineral (4.1