Recent changes in the climate-growth response of European larch ( Larix decidua Mill.) in the Polish Sudetes

Key message Recently observed temporal changes in the climate-growth relationship of larch in the Polish Sudetes suggest growth limitations in the future. Abstract Larches in the Sudetes are very sensitive to the currently changing climatic factors, and an extreme negative response to drought is observed. In this study, temporal changes in the climate-growth relationship of European larch were analyzed using moving-window correlation. Change-point detection analysis was performed to determine whether there is a temporal connection between tree-ring growth responses and changes in climatic factors trends. The Random Forest predictor importance determination method was used to establish the set of climatic factors that influence larch tree-ring growth the most and to show how this set changes over time. Additionally, cluster analysis was applied to find spatial growth patterns and to generalize the growth response of larch. The results indicate that the main clustering factor is altitude. Nevertheless, an increasing unification of the larch’s response to dominant climatic factors is observable throughout the whole study area. This unification is expressed in the increasingly positive and recently dominant effect of May temperature. A progressively negative influence of the temperature in the summer and late autumn of the year preceding growth was observed, as was an increasing influence of water availability in the summer months. The study indicates that there is a connection between the observed changes and the recent rapid rise in temperature, which has consequently had a negative influence on water availability. The growth of this tree species in the Sudetes is expected to be very limited in the future due to its sensitivity to drought, the predicted increase in temperatures and thermal extremes, and the decrease of the share of summer precipitation in the annual total.