Understanding the response of tree growth and drought vulnerability to climate and competition is critical for managing plantation forests. We analyzed the growth of Mongolian pines in six forests planted by the Three-North Shelter Forest Program with tree-ring data and stand structures. A retroactive reconstruction method was used to depict the growth-competition relationships of Mongolian pines during the growth period and their climatic responses under different competition levels. Drought vulnerability was analyzed by measuring the basal area increment (BAI) of different competition indices (CIs). In young trees, differences in BAIs in stands with different CIs were not statistically significant. After 15–20 years, medium- and high-CI stands had significantly lower tree-ring widths (TWs) and BAIs than the low-CI stands (p < 0.05). The standardized precipitation evapotranspiration index (SPEI), precipitation, relative humidity, and vapor pressure deficit were major factors affecting tree growth. On a regional scale, climate outweighed competition in determining radial growth. The relative contribution of climatic factors increased with the gap in SPEI between plantation sites and the native range, while the reverse pattern of the competition-growth relationship was observed. Drought reduced TWs and BAIs at all sites. Stands of different CIs exhibited similar resistance, but, compared with low-CI stands, high- and medium-CI stands had significantly lower recovery, resilience, and relative resilience, indicating they were more susceptible to drought stresses. Modeled CI was significantly negatively related to resistance, resilience, and relative resilience, indicating a density-dependence of tree response to drought. After exposure to multiple sequential drought events, the relative resilience of high-CI stands decreased to almost zero; this failure to fully recover to pre-drought growth rates suggests increased mortality in the future. In contrast, low-CI stands are more likely to survive in hotter, more arid climates. These results provide a better understanding of the roles of competition and climate on the growth of Mongolian pines and offer a new perspective for investigating the density-dependent recovery and resilience of these forests.

了解树木生长和干旱脆弱性对气候和竞争的反应对于管理人工林至关重要。我们利用树轮数据和林分结构分析了三北防护林计划种植的六片森林中蒙古松的生长情况。采用追溯重建方法刻画了生长期内蒙古松生长竞争关系及其在不同竞争水平下的气候响应。通过测量不同竞争指数（CI）的基础面积增量（BAI）来分析干旱脆弱性。在幼树中，具有不同 CI 的林分的 BAI 差异没有统计学意义。15-20 年后，中高 CI 林分的树轮宽度（TW）和 BAI 显着低于低 CI 林分（磷< 0.05)。标准化降水蒸散指数（SPEI）、降水量、相对湿度和水汽压差是影响树木生长的主要因素。在区域范围内，气候在决定径向增长方面胜过竞争。气候因素的相对贡献随着种植地点和原生范围之间SPEI的差距而增加，而竞争-增长关系的相反模式被观察到。干旱减少了所有地点的 TW 和 BAI。不同 CI 林分表现出相似的抗性，但与低 CI 林分相比，高和中 CI 林分的恢复、恢复力和相对恢复力显着降低，表明它们更容易受到干旱胁迫。建模 CI 与阻力、弹性和相对弹性显着负相关，表明树木对干旱的反应的密度依赖性。在经历多次连续干旱事件后，高 CI 林分的相对恢复力下降到几乎为零；未能完全恢复到干旱前的增长率表明未来死亡率会增加。相比之下，低 CI 林分更有可能在更热、更干旱的气候中生存。这些结果可以更好地了解竞争和气候对蒙古松生长的作用，并为研究这些森林的密度依赖性恢复和恢复能力提供了新的视角。未能完全恢复到干旱前的增长率表明未来死亡率会增加。相比之下，低 CI 林分更有可能在更热、更干旱的气候中生存。这些结果可以更好地了解竞争和气候对蒙古松生长的作用，并为研究这些森林的密度依赖性恢复和恢复能力提供了新的视角。未能完全恢复到干旱前的增长率表明未来死亡率会增加。相比之下，低 CI 林分更有可能在更热、更干旱的气候中生存。这些结果可以更好地了解竞争和气候对蒙古松生长的作用，并为研究这些森林的密度依赖性恢复和恢复能力提供了新的视角。