Abstract Under changing climate, temporal and spatial stability (stationarity) of growth responses of trees to weather and climate, which has often been presumed without explicit testing, is crucial for prediction of productivity and sustainability of forests. However, considering evolutionary adaptation of tree populations to wide spatiotemporal ecological gradients, extrapolation of linear responses, which could be observed in limited parts of the gradients (certain locality), can result in biased results. Accordingly, the plasticity of responses of tree-ring width of the eastern Baltic populations of Scots pine (Pinus sylvestris L.) to meteorological conditions across the regional climatic gradient was assessed using a mixed generalized additive model. The linear responses were assessed using a bootstrapped correlation analysis for comparison. The radial growth responses of the eastern Baltic population of Scots pine showed explicit regional gradients according to the local climates, indicating gradual shifts in the effects of winter temperature and summer moisture regime. Accordingly, temperature in late-winter and summer, as well as summer water deficit were identified as the main regional drivers of tree-ring width. Their effects were generally non-linear, indicating explicit spatiotemporal gradients in growth responses in the mid-part of species distribution. This also implied limited efficiency of simple linear models for the assessment of radial growth under moderate conditions. The responses to summer temperature indicated local optima, while the responses to drought index showed threshold values. The responses to winter temperature indicated positive effect of warming on growth. In some stands, specific non-stationary responses though were evident, suggesting that trees have adapted (specialized) to certain local climatic conditions, which are changing and thus explaining temporal shifts in growth responses. Nevertheless, the estimated responses suggested phenotypical adaptability limits of the eastern Baltic populations of Scots pine in a longer term, supporting the necessity of climate-smart management for sustainability of forest in the region in the future.

中文翻译：

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非线性区域天气-增长关系表明东波罗的海苏格兰松的适应性有限

摘要 在不断变化的气候下，树木对天气和气候的生长响应的时间和空间稳定性（平稳性）对于预测森林生产力和可持续性至关重要，这通常未经明确测试而被假定。然而，考虑到树木种群对广泛时空生态梯度的进化适应，线性响应的外推，可以在梯度的有限部分（某些地方）观察到，可能会导致有偏差的结果。因此，使用混合广义加法模型评估了波罗的海东部苏格兰松 (Pinus sylvestris L.) 种群的年轮宽度对区域气候梯度气象条件响应的可塑性。使用自举相关分析评估线性响应以进行比较。根据当地气候，波罗的海东部苏格兰松种群的径向生长响应显示出明显的区域梯度，表明冬季温度和夏季水分状况的影响逐渐变化。因此，冬末和夏季的温度以及夏季缺水被确定为树木年轮宽度的主要区域驱动因素。它们的影响通常是非线性的，表明物种分布中间部分的生长响应存在明确的时空梯度。这也意味着在中等条件下评估径向生长的简单线性模型的效率有限。对夏季温度的响应显示局部最优，而对干旱指数的响应显示阈值。对冬季温度的反应表明变暖对生长有积极影响。在某些林分中，特定的非平稳响应虽然很明显，但表明树木已经适应（专门）某些当地气候条件，这些气候条件正在发生变化，从而解释了生长响应的时间变化。尽管如此，估计的响应表明，从长远来看，波罗的海东部苏格兰松树种群的表型适应性限制，支持气候智能管理对未来该地区森林可持续性的必要性。