Fig. 1. Secondary forest carbon accumulation with increasing age under different driving conditions.

Drivers are a Annual mean downward shortwave (SW) radiation (Wm⁻²), b Maximum Cumulative Water Deficit (MCWD; mm yr⁻¹), c Annual mean precipitation (mm yr⁻¹), d Soil Cation Concentration (SCC; cmol(+) kg⁻¹), e Fire occurrences between 2001 and 2017, and f Number of deforestations prior to regrowth between 1985 and 2017, where 1 refers to areas that have only experienced the original conversion from old-growth forest to secondary forests during the period 1985–2017 with no subsequent deforestation events. The bar graph g shows the average importance ranking of the drivers (a–f), as well as Forest age, in influencing Aboveground Carbon (AGC) accumulation. The average ranking was calculated following 30 iterations of a conditional random-forest model. The importance has been ranked from least important (1) to most important (7) and the vertical dotted line separates environmental drivers (left) from anthropogenic disturbance drivers (right). Shading in a–f denotes the 95% confidence interval of the models, based on the median value of the initial data for each age—dots in figures. The error bars in g denote the 95% confidence interval.