Three decades following afforestation are sufficient to yield δ 13 C depth profiles

Vertical gradients in stable carbon isotope ratios (δ13C) in soil profiles can serve to approximate decomposition of organic matter under field conditions. This study tested the time (0, 30, and ≥ 150 y) required for the development of vertical δ13C profiles in topsoil by comparing arable, afforested and continuously forested sites, and showed that three decades following afforestation of former cropland are sufficient to develop distinct δ13C depth profiles.