Effects of natural regeneration on aboveground carbon stocks and annual carbon sequestration rates in Neltuma flexuosa populations of the Central Monte Desert, Argentina

Abstract

Introduction: While forests are widely recognized for carbon (C) sequestration, woodlands remain understudied—particularly in how different management regimes affect their C dynamics. Yet, these ecosystems can store significant amounts of C, and their restoration is a key strategy for climate change mitigation.Objectives: We assessed the long-term effects of natural regeneration on both aboveground C stocks and annual C sequestration rates in the Neltuma flexuosa population of the Central Monte Desert, comparing different woodland management regimes.Methods: C stocks were estimated using allometric models and Neltuma structure, while C sequestration rates were estimated based on stem growth rates obtained through dendrochronological techniques.Results: Woodland management regime alone was not a significant determinant of C stocks. However, well-preserved stands— characterized by larger trees—were positively associated with greater C stock and were distributed heterogeneously across different management regimes. However, well-conserved stands showed significantly lower C accumulation in areas with wood extraction and grazing than in restored areas with similar structural attributes, likely due to management practices. Regarding C sequestration, stands with high tree density but small diameter classes tended to sequester less C than those with similar density but larger diameter classes.Conclusions: Large trees contributed more to C stocks in restored areas, which aligns with the idea that large individuals are critical for driving C accumulation. Nonetheless, managing high-density stands of trees at their peak growth stage in grazed areas may enhance C sequestration rates. These findings offer valuable insights for designing restoration strategies focused on maximizing C stocks in woodlands.Implications for Practice: Restoration strategies should focus on promoting the growth of large trees even under grazing and wood extraction regimes, as they are key to maintaining C stocks. Selective thinning in high-density stands emerges as a promising management tool, as it reduces competition and enhances tree growth, ultimately optimizing C sequestration. The use of extracted stems for building (e.g. perimeter fencing) in grazing fields can help retain C within the system for extended periods. Moreover, occasional grazing could be a valuable tool to enhance C Sequestration rates, provided the trade-offs between positive and negative impacts are thoroughly explored and considered.