Analyzing asymmetries in the response of European beech to precipitation anomalies in various stand and site conditions using decadal diameter censuses

• Asymmetric effects of precipitation anomalies on beech growth were detected with forest inventories. More extreme had disproportionally large diameter growth. Growth reductions in dry extremes 3 times greater than increases wet extremes. Stand basal area, the social status a tree and species diversity significantly affect In temperate forests, precipitation-productivity relationships have usually been considered linear symmetric, i.e. under conditions nominal variability, trees are able to compensate for reduced during increased However, severely dry/wet responses may be nonlinear asymmetrical. Forest inventory data standardized drought indexes such as Standardized Precipitation Index (SPI) can used test asymmetries relationship between aboveground net primary production precipitation. Based from Slovenia (51,734 plots, 365,885 individual measurements period 1992-2013), we estimated effect increment European various climatic, site stand conditions. Beech responds asymmetrically even moderately variable An model tree, 5 stand, 6 4 climate variables explaining 32.6% total variance suggests that extremely periods 3.0 periods. A comparison 108 natural cubic spline models shows giving more weight deviations average summer explains compared using SPI summers two censuses. We conclude negative asymmetry temporal scale decade much coarser tree-ring chronologies. |SPI| > 1.5 trend 60% plots at an rate -0.2/year, contributed < 1% (57%) (4%) factors. At same magnitude density levels competition, is expected grow better structurally compositionally diverse stands.