Abstract

Vegetation recovery following disturbance fundamentally alters soil carbon dynamics through complex interactions between carbon inputs, decomposition processes, and soil biological communities. This comprehensive study examines vegetation recovery effects on soil carbon accumulation and mineralization across 178 recovery sites spanning 5-50 years post-disturbance in temperate and boreal ecosystems. We monitored natural succession, active restoration, and abandoned agricultural sites using isotopic labeling (¹³C), soil respiration measurements, and incubation experiments to quantify carbon inputs, mineralization rates, and net accumulation patterns. Results demonstrate that vegetation recovery significantly enhances soil carbon accumulation, with rates increasing from 0.3 ± 0.2 Mg C ha⁻¹ year⁻¹ in early succession (5-10 years) to 2.1 ± 0.6 Mg C ha⁻¹ year⁻¹ in mature recovering systems (>30 years). However, concurrent increases in mineralization rates (1.8-fold) partially offset accumulation benefits, with net carbon storage efficiency declining from 73% in early stages to 45% in mature recovery sites. Isotopic analysis reveals that new vegetation-derived carbon comprises 67% of total soil carbon after 25 years of recovery, indicating substantial turnover of legacy carbon pools. Depth profile analysis shows 78% of new carbon accumulation occurs in surface layers (0-30 cm), while deeper soils (30-60 cm) show enhanced mineralization of pre-existing organic matter. Microbial biomass carbon increases 4.3-fold during recovery, with fungal:bacterial ratios shifting from 0.8 to 2.4, enhancing organic matter stabilization. Recovery type significantly influences carbon dynamics, with forest restoration achieving highest accumulation rates (2.8 ± 0.7 Mg C ha⁻¹ year⁻¹), followed by grassland restoration (1.6 ± 0.4 Mg C ha⁻¹ year⁻¹) and natural succession (1.2 ± 0.5 Mg C ha⁻¹ year⁻¹). Climate interactions are pronounced, with carbon accumulation rates 34% higher in cool-humid conditions compared to warm-dry environments. Economic valuation reveals carbon benefits worth $156-420 ha⁻¹ year⁻¹, though high spatial variability (CV = 45-67%) complicates accurate quantification. These findings demonstrate that vegetation recovery provides substantial but variable carbon sequestration benefits, requiring consideration of temporal dynamics, ecosystem context, and management strategies for accurate carbon accounting and climate mitigation planning.