Key messageDouglas-fir growth correlates with the climate, the soil moisture regime, and the soil nutrient status, reflecting a broad physiological amplitude. Even though planting this non-native tree species is suggested as a viable strategy to improve adaptiveness of European forests to a more extreme climate and to assure future productivity, the expected temperature increase may induce a decline in forest stand productivity for Douglas-fir in already warm and dry regions.ContextTree species selection is one of the most important forest management decisions to enhance forest productivity and stand stability on a given site. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii), a non-native species from north-western America, is seen as an important additional species option for adapting Central European forests to a changing climate.AimsThis study assesses Douglas-fir forest productivity derived from site conditions. We investigate climatic and physico-chemical soil characteristics and productivity of 28 mature Douglas-fir stands growing on siliceous, as well as carbonate bedrock material in southern Germany and north-eastern Austria.MethodsThe importance of climatic and physico-chemical soil characteristics was analyzed with the machine learning method Random Forests.ResultsThe results show that Douglas-fir growth correlates with climate, soil moisture, and soil nutrient availability derived from ten climatic and physico-chemical soil parameters.ConclusionThe broad pH optimum between 4.5 and 7.2 reflects the broad physiological amplitude of Douglas-fir, and no significant differences were detectable between carbonate and siliceous bedrock. We also conclude that climate change may induce a forest stand productivity decline, because lower productivity with the highest mean summer temperature across our study range was observed at the warmest sites in Eastern Austria.

中文翻译：

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来自场地条件的林分生产力：对中欧老花旗松林 (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) 的评估

关键信息花旗松的生长与气候、土壤水分状况和土壤养分状况相关，反映了广泛的生理幅度。尽管种植这种非本地树种被认为是提高欧洲森林对更极端气候的适应性并确保未来生产力的可行策略，但预期的温度升高可能会导致花旗松的林分生产力下降温暖和干旱地区。背景树种选择是最重要的森林管理决策之一，以提高森林生产力和给定地点的林分稳定性。花旗松 (Pseudotsuga menziesii (Mirb.) Franco var. menziesii)，一种来自美国西北部的非本土物种，被视为使中欧森林适应不断变化的气候的重要附加物种选择。目的本研究评估来自场地条件的花旗松森林生产力。我们调查了德国南部和奥地利东北部生长在硅质和碳酸盐基岩材料上的 28 个成熟花旗松林的气候和理化土壤特征和生产力。方法分析气候和理化土壤特征的重要性机器学习方法随机森林。结果结果表明，从十个气候和物理化学土壤参数得出的花旗松生长与气候、土壤水分和土壤养分有效性相关。结论 4.5 和 7.2 之间的广泛 pH 值反映了广泛的生理幅度花旗松，碳酸盐和硅质基岩之间未检测到显着差异。我们还得出结论，气候变化可能导致林分生产力下降，因为在奥地利东部最温暖的地点观察到在我们研究范围内的夏季平均温度最高的生产力较低。