Abstract In dry woodland regions, silvopastures have emerged as a promising option to balance cattle production, carbon storage and biodiversity. However, one of the major challenges in these systems, particularly when implemented in a matrix of natural vegetation, is the preservation of tree populations in the face of management actions implemented by ranchers to control woody encroachment. Here, we investigate the extent of that tradeoff by analyzing the impact of woody encroachment control practices on carbon storage in silvopastures of the Argentine Dry Chaco. First, we analyze tree density and carbon storage in aboveground woody biomass for silvopastures and woodlands at 24 sites in five properties across the Argentine Dry Chaco. Then, we characterize vegetation management goals and actions of ranchers who have adopted silvopastures in that same region, combining field assessments, high-resolution imagery analysis, characterization of site history, and surveys. We find that woody biomass in silvopastures retains an average of 64 % of the carbon present in aboveground biomass in intact woodlands (28.8 Mg C ha−1). However, we also find that this storage capacity decreases by 12 % with each woody encroachment control intervention, due to these interventions’ negative effects on tree density. Ranchers expressed concern about tree mortality, but also indicated low profitability of wood products and highlighted woody encroachment as a major issue for livestock production. Therefore, ranchers feel they have no choice but to continue preventing woody encroachment, even if this implies the gradual depletion of tree populations. Understanding how ranchers manage silvopastures, and how that management affects the provision of ecosystem services, is essential and will require more careful long-term monitoring and evaluation. This is particularly true in agricultural frontiers such as the Argentine Dry Chaco, where silvopastoral systems have the potential to mitigate the seemingly irremediable conflict between commodity production and nature conservation.

中文翻译：

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难以兑现的承诺：干查科森林牧场的植被利用和地上碳储存

摘要 在干旱林地地区，林场已成为平衡牛生产、碳储存和生物多样性的一种有前景的选择。然而，这些系统的主要挑战之一，尤其是在自然植被矩阵中实施时，是在牧场主为控制木本侵占而实施的管理行动面前保护树木种群。在这里，我们通过分析木质侵占控制实践对阿根廷干查科林场碳储存的影响来研究这种权衡的程度。首先，我们分析了整个阿根廷干查科地区 24 个地点的林场和林地地上木质生物量的树木密度和碳储存量。然后，我们描述了在同一地区采用林场的牧场主的植被管理目标和行动，结合实地评估、高分辨率图像分析、场地历史特征和调查。我们发现林场中的木质生物量保留了完整林地地上生物量中平均 64% 的碳（28.8 Mg C ha-1）。然而，我们还发现，由于这些干预对树木密度的负面影响，每次木本侵占控制干预都会使该存储容量降低 12%。牧场主对树木死亡表示担忧，但也表示木制品的利润率低，并强调木材侵占是畜牧生产的一个主要问题。因此，牧场主觉得他们别无选择，只能继续防止木本侵占，即使这意味着树木种群的逐渐枯竭。了解牧场主如何管理林场，以及这种管理如何影响生态系统服务的提供，至关重要，需要更仔细的长期监测和评估。在阿根廷干查科等农业前沿地区尤其如此，在那里林牧系统有可能缓解商品生产与自然保护之间看似无法弥补的冲突。