Tree growth responses to severe droughts for assessment of forest growth potential under future climate

17 S.

e-journal

200212503

More frequently occurring droughts, related to climate change, lead to reduced growth and loss of vitality in trees. The recent drought of 2018 was extreme, long-lasting and resulted in high evaporative demands due to the concurrent high temperatures. The aim of this study was to compare the drought resilience of nine temperate tree species in the Netherlands, and to determine their responses to the severe drought of 2018 in comparison with five earlier drought events since 1970. To assess drought effects on tree species, we analysed tree-ring series of 678 trees in 45 plots throughout the Netherlands. Resilience indices were calculated based on growth reactions and growth recovery after drought. Furthermore, the impact of drought events on species productivity was quantified. We observed species-specific differences in growth responses to drought timing. All species in nearly all sites responded with growth reductions to drought, except sessile oak (Quercus petraea (Matt.) Liebl.). The most productive species in our study were found to be drought sensitive, with productivity losses of up to 30 % during drought in some sites.
Keywords: Climate change; Drought resilience; Dendrochronology; Temperate tree species; Netherlands.