Tree recruitment is affected by numerous biotic and abiotic factors, including climate. However, the relative importance of climate variables in empirical models of tree recruitment remains to be evaluated. We fitted models of tree recruitment to 26 species in the province of Quebec, Canada. For a better understanding of the recruitment process, we used a two-part model to distinguish recruitment occurrence from abundance. The relative importance of the different variables was assessed using Akaike weights. Our main hypothesis was that climate is one of the major drivers of tree recruitment. Our results showed that growing degree-days counted among the major drivers of recruitment occurrence but not of recruitment abundance. Stand variables, such as the presence and abundance of adult trees of the species, and broadleaved and coniferous basal areas were found to be relatively more important than all the climate variables for both recruitment occurrence and abundance. Species occupancy within a 10-km radius also had a significant effect on recruitment occurrence for two-thirds of the species, but it was less important than growing degree-days and other stand variables. Climate change is expected to improve the suitability of habitats located at the northern edge of species distributions. However, our model predictions point to a low probability of colonization in newly suitable habitats in the short term.

中文翻译：

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气候对加拿大魁北克省树木补充发生和丰度的影响

树木的补充受到许多生物和非生物因素的影响，包括气候。然而，气候变量在树木补充经验模型中的相对重要性仍有待评估。我们将树木补充模型应用于加拿大魁北克省的 26 个树种。为了更好地理解招聘过程，我们使用了两部分模型来区分招聘的发生和丰富。使用 Akaike 权重评估不同变量的相对重要性。我们的主要假设是气候是树木补充的主要驱动因素之一。我们的结果表明，学位日的增加是招聘发生的主要驱动因素，但不是招聘丰富的主要驱动因素。立场变量，例如该物种成年树木的存在和丰富度，研究发现阔叶树和针叶树的基底面积对于补充发生和丰度而言比所有气候变量都相对更重要。10公里半径内的物种占有率对三分之二的物种的补充发生也有显着影响，但其重要性不如生长度日和其他林分变量。气候变化预计将改善物种分布北部边缘栖息地的适宜性。然而，我们的模型预测表明，短期内在新的适宜栖息地定植的可能性很低。但它不如学位日增长和其他立场变量重要。气候变化预计将改善物种分布北部边缘栖息地的适宜性。然而，我们的模型预测表明，短期内在新的适宜栖息地定植的可能性很低。但它不如学位日增长和其他立场变量重要。气候变化预计将改善物种分布北部边缘栖息地的适宜性。然而，我们的模型预测表明，短期内在新的适宜栖息地定植的可能性很低。