Data: Long-Term Trajectories and Asynchronous Soil Recovery in a Semi-Arid Ecosystem

Forest management in the Caatinga dry forest of northeastern Brazil affects soil carbon and nitrogen stocks, but the recovery dynamics of exchangeable cations, base saturation, and electrical conductivity remain poorly understood. Despite the semi-arid climate and slow vegetation regeneration, Brazilian legislation still allows 15-year cutting cycles, identical to those of humid forests. This study evaluated the suitability of this legal cycle by analyzing soil chemical properties along a chronosequence of hyperxerophilous Caatinga vegetation (0.5, 6, 9, 12, 25, 50 years after clear-cutting and >80-year reference forest). Soil samples (0–5, 5–10, 10–20 cm) were analyzed for pH, total organic carbon (TOC), electrical conductivity (EC), and exchangeable Ca²⁺, Mg²⁺, K⁺, and Na⁺. Soil pH, TOC, and base saturation increased with regeneration time, with logistic models estimating 90% recovery after 48.7, 138.3, and 16.5 years, and 99% recovery after 169.2, 341.5, and 37.9 years. Conversely, EC and Na⁺ decreased throughout the chronosequence, with 99% of their reduction occurring after 78.7 and 71.8 years. TOC showed the slowest recovery rate (B = 0.95), while base saturation responded the fastest (B = 8.98), revealing divergent sensitivities among chemical indicators. Exchangeable Ca²⁺, Mg²⁺, and K⁺ were positively correlated with pH and TOC, whereas Na⁺ and EC exhibited negative associations. Overall, the results indicate that 15-year cutting cycles are insufficient to restore Caatinga soil fertility, allowing recovery of only ~50% of nutrient stocks. Extended fallow periods of at least 35–70 years are necessary to ensure full restoration of soil chemical quality and promote long-term ecosystem resilience.