Lowland forests in Europe went through dramatic changes in the last century. Data accumulated from the nature reserve Buky u Vysokého Chvojna in the Czech Republic provide a unique opportunity to follow beech forest development using a time series consisting of five points in time from 1926 to 2019. Our goal was to reconstruct changes in plant species richness and plant community composition over this period. Based on the available data, we concluded that vascular plant species richness per plot declined by at least 50%, possibly by 75% since 1951. Compositional dissimilarities between the first survey and subsequent resurveys revealed a directional trajectory of vegetation changes. Treating time as an environmental factor and tree canopy cover as a covariable (and vice versa) in canonical correspondence analysis permutation tests where only the herbaceous layer was used, time turned out to be much more important. Variance partitioning revealed that time explained 28.1% and tree canopy 4.2% of the variation in the species data. The two variables together explained 36.8% of the variance, revealing that the shared effect of these two variables was 4.5%. Ellenberg-type indicator values point to a possible role of increasing nitrogen and decreasing pH. Several other factors potentially responsible for observed vegetation changes are discussed.

欧洲的低地森林在上个世纪经历了巨大的变化。从捷克共和国Buky uVysokéhoChvojna自然保护区收集的数据提供了一个独特的机会来追踪山毛榉森林的发展，使用的时间序列包括1926年至2019年的五个时间点。我们的目标是重建植物物种丰富度和植物的变化此期间的社区组成。根据现有数据，我们得出的结论是，自1951年以来，每块地的维管束植物物种丰富度至少下降了50％，可能下降了75％。第一次调查与随后的重新调查之间的成分差异揭示了植被变化的方向轨迹。在仅使用草本层的规范对应分析置换测试中，将时间视为环境因素，将树冠覆盖率视为协变量（反之亦然），时间显得更为重要。方差划分表明，时间解释了物种数据变化的28.1％，树冠4.2％。这两个变量共同解释了36.8％的方差，表明这两个变量的共同影响为4.5％。Ellenberg型指标值指出了增加氮和降低pH的可能作用。讨论了可能导致观测到的植被变化的其他几个因素。这两个变量共同解释了36.8％的方差，表明这两个变量的共同影响为4.5％。Ellenberg型指标值指出了增加氮和降低pH的可能作用。讨论了可能导致观测到的植被变化的其他几个因素。这两个变量共同解释了36.8％的方差，表明这两个变量的共同影响为4.5％。Ellenberg型指标值指出了增加氮和降低pH的可能作用。讨论了可能导致观测到的植被变化的其他几个因素。