Contrasting changes in soil carbon under first rotation, secondary and historic woodland in England and Wales

This study investigates changes in soil carbon under woodland combining data from the National Soil Inventory of England and Wales with data from the National Inventory of Woodlands and Trees to create a unique dataset with woodland management information at the sites where soil carbon was measured in 1980 and 2003. Three woodland management stages were compared: first rotation (i.e. recently planted on land not previously under woodland and not yet harvested), second rotation (i.e. harvested at least once), and historic woodlands. Woodlands in their first rotation demonstrated a reduction (p < 0.01) in topsoil organic carbon content typically losing over 2% per year, whereas no change (p ≥ 0.10) was observed for the other two woodland types. This large reduction in organic carbon could not be statistically explained by a higher inherent soil carbon, as the mean soil carbon content of the first rotation and second rotation woodlands were not (p ≥ 0.50) different. The average age of the woodlands under first rotation was 42 years, indicating that the period of significant soil carbon loss could go on for about 40 years after planting.