Conifer populations across wide geographical ranges often demonstrate adaptation to local environments related to heterogeneous climatic conditions. Long-term provenance experiments are powerful tools for evaluating transfer effect and detecting a home-site advantage in transplant performance. The transplant responses of Sakhalin fir (Abies sachalinensis), which is widely distributed in the boreal forests of Hokkaido, northern Japan, were evaluated by >30-year-old provenance trials using seed sources throughout Hokkaido and conducted at two sites, namely Akkeshi (AKS) and Bibai (BBI), with contrasting conditions in climates of snowfall in winter and sun exposure in summer. Intraspecific variations among seed sources were observed in survival rate, tree height, diameter, and volume (V) at the both sites. To test the home-site advantage, we used the transplant performance (survival rate × V) and two transfer distances; the geographic horizontal distance (GDIST) between seed sources and the sites; as well as the environmental distance (EDIST) that was calculated from principal components of candidate climatic factors. In general, the decrease of the transplant performance with increasing transfer distance was detected at the both sites, thus indicating the remarkable home-site advantage of this species. The best models using EDIST at site AKS and using GDIST at site BBI were selected, and larger transfer effect was predicted at site AKS. Distinct adaptive divergence among seed sources at site AKS was consistent with already known intraspecific variations in juvenile-growth and some tolerances to snowfall-related stresses. The climatic gradient associated with winter conditions in Hokkaido might involve asymmetric local adaptation in A. sachalinensis.

中文翻译：

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长期种源试验揭示库页岛冷杉（Abies sachalinensis）对不同气候条件的局部适应

跨越广泛地理范围的针叶树种群通常表现出对与异质气候条件相关的当地环境的适应。长期的起源实验是评估移植效果和检测移植性能的本地优势的有力工具。库页岛冷杉（Abies sachalinensis）广泛分布于日本北部北海道的北方森林，其移植反应通过使用北海道各地种子来源的 > 30 年历史的种源试验进行评估，并在两个地点进行，即 Akkeshi（ AKS) 和 Bibai (BBI)，在冬季降雪和夏季阳光照射的气候条件下形成对比。在存活率、树高、直径和体积方面观察到种子来源之间的种内差异（V) 在两个站点。为了测试主场优势，我们使用移植性能（存活率 ×  V) 和两个传输距离；种子源和站点之间的地理水平距离（GDIST）；以及根据候选气候因子的主成分计算的环境距离 (EDIST)。总的来说，在两个地点都检测到移植性能随着转移距离的增加而下降，从而表明该物种具有显着的家园优势。选择了在AKS站点使用EDIST和在BBI站点使用GDIST的最佳模型，并且在站点AKS预测了更大的转移效应。站点 AKS 种子源之间明显的适应性差异与已知的幼鱼生长的种内变化和对降雪相关压力的一些耐受性一致。与北海道冬季条件相关的气候梯度可能涉及不对称的局部适应A. sachalinensis。