Active ecological restoration drives rapid soil chemistry and carbon change in Mistbelt Afromontane forests

Land degradation severely threatens forest ecosystems, especially soil organic carbon (SOC) storage, which is vital for climate, nutrients, and productivity. The Mistbelt forests in South Africa’s Eastern Cape are facing growing deforestation, wildfires, and invasive species, which are accelerating soil degradation and carbon (C) loss. This study assessed how active restoration drives rapid soil chemistry and C change in Mistbelt Afromontane forests over seven years. A factorial experimental design was utilised, and soil samples were collected from restored and reference sites at two depths (0 – 30 cm and 30 – 60 cm) and analysed for chemical and humification parameters. A three-way ANOVA, principal component analysis (PCA), and K-means clustering were applied to assess restoration effects and identify key soil response indicators. Restoration significantly enhanced soil properties, with active C pools increasing from 758 to 1025% in the topsoil ( p < 0.05), total nitrogen (N) rising between 0.48% and 1.03% ( p < 0.01), and pH values ranging from 5.13 to 7.08 ( p > 0.05). Humification indices also improved, with a humification rate (HR) ranging from 43% to 84% ( p < 0.05) and a humification index (HI) ranging from 24% to 75% ( p > 0.05). PCA identified SOC (0.47 – 1.29%) and total N as key distinguishing factors from reference sites. This study found that active ecological restoration in the Mistbelt forests significantly improved soil chemical properties, particularly in the topsoil, with increased SOC and nutrient cycling. These results demonstrate that active restoration can rapidly enhance SOC dynamics, though site-specific variability highlights the need for adaptive management strategies.