With progressive climate change, the chemical defense in European beech (Fagus sylvatica L.) is likely to change, which might impact its fitness and ability to establish beyond its current northern distribution limit. We studied the phenolic defense in six beech provenances grown in three common gardens in Norway the two first years after planting.

We analyzed low molecular weight phenolic compounds by HPLC and condensed tannins by the acid-butanol assay. Sampling year explained most of the variance in phenolic defense, followed by environment (growing location), while the genetic background (provenance) showed the least explanatory power. After the first year in the field, the northernmost growing location had about 70% higher concentration of low molecular weight phenolics than the southern growing locations. The concentrations of condensed tannins, however, were lowest in the north. The mean concentration of total low molecular weight phenolics was twice as high after the first year compared to the second year. After the second year, the differences between the growing locations in many cases disappeared. The differences between the growing locations are probably caused by differences in temperature and soil fertility, while we attribute the decrease in low molecular weight phenols from the first to the second year to decreased water and nutrient stress, as well as aging. Our results suggest that intraspecific variations in concentration and composition of phenolic compounds in beech are caused by differences in the environment to a greater extent than the genetic background, which may indicate fast changes in chemical defense with climate change.

随着气候的不断变化，欧洲山毛榉（Fagus sylvatica L.）的化学防御作用可能会发生变化，这可能会影响其健康状况和建立超出其目前北方分布范围的能力。在种植后的头两年，我们研究了挪威三个常见花园中种植的六种山毛榉种源的酚类防御作用。

我们通过HPLC分析了低分子量的酚类化合物，并通过酸-丁醇分析了缩合的单宁。采样年份解释了酚类防御的大部分变化，其次是环境（生长位置），而遗传背景（来源）显示的解释力最低。在该田地的第一年之后，最北端的种植区的低分子量酚类化合物的浓度比南端的种植区高出约70％。但是，冷凝的单宁浓度在北部最低。与第二年相比，第一年之后总的低分子量酚类化合物的平均浓度是其两倍。第二年之后，在许多情况下，生长地点之间的差异消失了。生长地点之间的差异可能是由于温度和土壤肥力的差异所致，而我们将低分子量苯酚从第一年到第二年的减少归因于水分和养分胁迫以及衰老的减少。我们的结果表明，山毛榉中酚类化合物浓度和组成的种内变化是由于环境差异比遗传背景造成的程度更大，这可能表明化学防御随着气候变化而快速变化。