At semi‐arid forest margins, increasing climatic stress combined with disturbances like wildfire threatens to cause widespread forest loss. However, forest resilience is likely to vary over gradients of topoclimate and vegetation characteristics, and the influences of local climate and tree species on tree regeneration remain key uncertainties in assessing forest recovery from wildfire. We surveyed tree regeneration 9–15 yr post‐fire at 397 gridded field plots across four sites at a lower montane forest‐steppe ecotone in the eastern Sierra Nevada, California, USA, and then used statistical modeling to characterize how the probability of tree regeneration presence for different species varied along gradients of fire severity, topoclimate, and post‐fire vegetation structure and composition. Tree regeneration was absent in half the field plots, and only 19% of plots contained >250 seedlings and saplings per ha, suggesting potential for regeneration failure and forest loss. Tree regeneration composition was consistent with shifts away from Jeffrey pine (Pinus jeffreyi) and toward drought‐tolerant pinyon pine (P. monophylla) and mountain mahogany (Cercocarpus ledifolius). Tree regeneration was strongly associated with trees that survived fire indicating tree cover is crucial to buffer establishment against climatic stress. Based on projected future water balance, the likelihood of tree regeneration at these sites does not decline substantially by the end of the century. Consequently, these forests appear to be resilient to climate change under a low‐severity fire regime, but large patches of high‐severity fire are likely to shift vegetation away from forest. Our results highlight the importance of facilitation and future water balance in maintaining semi‐arid forest margins that burn at low severity while high‐severity fire threatens to convert forest to steppe or invasive grasslands.

中文翻译：

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雨影森林边缘对低度烈火和气候变化具有抵抗力，但对高度烈火没有抵抗力

在半干旱的森林边缘，气候压力的增加以及野火之类的干扰有可能造成广泛的森林损失。然而，森林的复原力可能会随着地形和植被特征的梯度而变化，并且当地气候和树木种类对树木再生的影响仍然是评估野火森林恢复的主要不确定因素。我们在美国加利福尼亚内华达州东部山地森林草原草原交错带的四个地点的397个网格地块上，对火灾后9-15年的树木再生进行了调查，然后使用统计模型来表征树木再生的概率不同物种的存在随火灾严重性，地形气候以及火灾后植被结构和组成的梯度变化。一半的田间地块都没有树木再生，每公顷仅19％的地块每公顷包含超过250棵树苗和树苗，这表明有再生失败和森林丧失的可能性。树木的再生组成与离开Jeffrey松树（杰弗里松（Pinus jeffreyi）和耐旱的松树松（P. monophylla）和山桃花心木（Cercocarpus ledifolius）。树木的再生与能在火中幸存的树木紧密相关，这表明树木的覆盖对于缓冲建立抵抗气候压力至关重要。根据预计的未来水平衡，到本世纪末，这些地点树木再生的可能性不会显着下降。因此，这些森林在低度烈火下似乎可以抵御气候变化，但是大片高烈度大火可能会使植被远离森林。我们的结果凸显了促进和未来水平衡在保持低干旱程度的半干旱森林边缘而高强度火灾威胁将森林转变为草原或入侵草地方面的重要性。