Lifting the profile of deep soil carbon in New Zealand’s managed planted forests

This small case study highlights that New Zealand's planted forests contain substantial stocks of DSOC, much of which is older than the current forest land use. The deep soils were dominated by reactive metals, and although the age of DSOC suggest long-term stability, the large contribution of reactive metal-mediated SOC stabilisation may indicate vulnerability to warming soil temperatures relative to other climate change factors. There is a pressing need to expand soil sampling to greater depths and establish a robust SOC baseline for New Zealand's planted forests. This is essential for enabling spatial predictions of DSOC dynamics under future climate scenarios, identify the key controls on DSOC persistence, and concomitant impacts on forest ecosystem function and resilience.