Fig. 4From: A meta-analysis of changes in soil organic carbon stocks after afforestation with deciduous broadleaved, sempervirent broadleaved, and conifer tree speciesThe effect of plantation age group on the rate of SOC stock change of different tree species at soil depths of a 0–20 cm, b 20–40 cm and c 40–60 cm. Dots with error bars denote the overall rate of SOC stock change and the 95% confidence interval. The number of observations is indicated in parentheses. A different letter at the top of the bars indicates a difference significant at the P < 0.05 levelBack to article page