Faming Wang, Yongzhen Ding, Emma J. Sayer, Qinlu Li, Bi Zou, Qifeng Mo, Yingwen Li, Xiaoliang Lu, Jianwu Tang, Weixing Zhu and Zhian Li
Tropical forest soils worldwide contain more carbon than the atmosphere but unfortunately, these soil carbon stocks are often reduced or depleted during deforestation and land-use change. Rapid tree growth in plantations or young secondary tropical forests can sequester large amounts of carbon in biomass, but we know little about the recovery of soil carbon stocks after disturbance. To investigate this, we measured stocks of soil carbon in a secondary forest and a Eucalyptus plantation, which were established on severely degraded land in China in the 1960s. The secondary forest had similar carbon stocks in trees and surface soil layers compared to old-growth forest. However, most of the carbon in the soil was still relatively new and the amount of older stabilized carbon stored in deeper soil layers was still much lower than in old-growth forest. In addition, repeated harvesting in plantations slowed the recovery of soil carbon stocks compared to secondary forest. We conclude that the loss of primary tropical forests greatly reduces carbon storage in the soil, which could take hundreds of years to recover. Current calculations are likely to overestimate soil carbon storage in secondary tropical forests and plantations.
Image caption: The bare land before restoration in 1959 (A) and Eucalyptus plantation (B) and restored secondary forest (C) at the Xiaoliang Station, China in 2009. Photos by Zuoyue Yu (A) and Faming Wang (B,C)