Benomar Lahcen, Bousquet Jean, Perron Martin, Beaulieu Jean, Lamara Mebarek
Institut de Recherche sur les Forêts, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC, Canada.
Centre d'Étude de la Forêt et Institut de Biologie Intégrative et des Systèmes, Faculté de Foresterie, de Géographie et de Géomatique, Université Laval, Québec, QC, Canada.
Front Plant Sci. 2022 Jul 6;13:920852. doi: 10.3389/fpls.2022.920852. eCollection 2022.
Global warming is predicted to extend the growing season of trees and plants, and advance spring phenology. However, intensification of extreme climate events in mid-latitude forests, from weakening of the jet stream and atmospheric blockings, may expose trees to increased risk associated with more frequent late-spring frosts. Still, little is known regarding the intraspecific variation in frost tolerance and how it may be shaped by local adaptation to the climate of seed origin. As part of an assisted migration trial located in different bioclimatic zones in the province of Quebec, Canada, and following an extensive late-spring frost that occurred at the end of May 2021, we evaluated the frost damages on various white spruce () seed sources tested on three sites (south, central, and north). The severity of frost damages was assessed on 5,376 trees after the cold spell and an early spring warming which advanced bud flush by approximately 10 days on average. The frost damage rate was similar among sites and seed sources and averaged 99.8%. Frost damage severity was unrelated to the latitude of seed origin but was variable among sites. The proportion of severely damaged trees was higher in the northern site, followed by central and southern sites. The proportion of severely damaged trees was linearly and inversely related to tree height before the frost event. Apical growth cancelation was not significantly different among seed sources including local ones, and averaged 74, 46, and 22%, respectively, in central, northern, and southern plantation sites. This study provides recommendations to limit the loss of plantation productivity associated with such a succession of spring climate anomalies. Implications for seed transfer models in the context of climate change and productivity of spruce plantations are discussed in the light of lack of local adaptation to such pronounced climate instability and ensuing large-scale maladaptation.
预计全球变暖将延长树木和植物的生长季节，并使春季物候提前。然而，中纬度森林中极端气候事件的加剧，源于急流减弱和大气阻塞，可能会使树木面临与更频繁的晚春霜冻相关的更高风险。尽管如此，关于耐寒性的种内变异以及它如何受种子来源地气候的局部适应影响，我们仍知之甚少。作为一项在加拿大魁北克省不同生物气候区进行的辅助迁移试验的一部分，在2021年5月底发生的一次广泛的晚春霜冻之后，我们评估了在三个地点（南部、中部和北部）测试的各种白云杉（）种子来源的霜冻损害情况。在寒潮和早春变暖之后，对5376棵树评估了霜冻损害的严重程度，早春变暖使芽萌发平均提前了约10天。各地点和种子来源的霜冻损害率相似，平均为99.8%。霜冻损害的严重程度与种子来源地的纬度无关，但在不同地点有所不同。北部地点严重受损树木的比例较高，其次是中部和南部地点。严重受损树木的比例与霜冻事件前的树高呈线性反比关系。包括本地种子来源在内的各种子来源的顶芽生长抑制没有显著差异，在中部、北部和南部种植地点分别平均为74%、46%和22%。本研究提供了一些建议，以限制与这种春季气候异常相继出现相关的人工林生产力损失。鉴于缺乏对这种明显的气候不稳定以及随之而来的大规模不适应的局部适应，讨论了气候变化背景下种子转移模型对云杉人工林生产力的影响。
