Growing faster, longer or both? Modelling plastic response of <i>Juniperus communis</i> growth phenology to climate change

Aim Plant growth and phenology respond plastically to changing climatic conditions in both space time. Species-specific levels of plasticity determine biogeographical patterns the adaptive capacity species climate change. However, a direct assessment spatial temporal variability radial dynamics is complicated, because long records cambial do not exist. Location Sixteen sites across European distribution margins Juniperus communis L. (the Mediterranean, Arctic, Alps Urals). Time period 1940–2016. Major taxa studied communis. Methods We applied Vaganov–Shashkin process-based model wood formation estimate trends growing season duration kinetics since 1940. assumed that J. would exhibit spatially temporally variable reflecting local conditions. Results Our simulations indicate regional differences plastic responses warming. The mean longest at Mediterranean and, recently, there has been significant trend towards its extension up 0.44 days/year. this stimulating effect longer counteracted by declining summer rates caused amplified drought stress. Consequently, overall simulated ring widths are marginal Mediterranean. In contrast, durations seasons Arctic show lower mostly non-significant trends. spring follow increasing temperatures, leading increase 0.32 %/year. Main conclusions This study highlights widely distributed shrubs warming: an earlier onset activity offsets negative effects droughts conversely, intensification during short Arctic. Such responsiveness allows woody plants adapt pace