Short-term stem diameter variations in irrigated and non-irrigated stone pine (Pinus pinea L.) trees in a xeric non-native environment

center dot Key Message Irrigation of adult stone pine trees growing in a xeric non-native habitat had positive effects not only in stem diameter growth but also in tree response to climatic variability. center dot Context Stone pine is a key species from Mediterranean Europe increasingly planted in South America. The knowledge about irrigation impact on short-term stem diameter dynamics is still limited in non-native arid areas. center dot Aims To improve our understanding of the effect of irrigation on (1) stem diameter changes of stone pine trees in a drought-prone environment in Chile and (2) the sensitivity of the species to weather conditions. center dot Methods We studied daily stem diameter changes in irrigated and non-irrigated 31-year-old stone pine trees during a growing season with below average precipitation in Chile. Short-term diameter changes were recorded using high-resolution dendrometers. The detrended daily stem diameter changes, expressing tree water status, were correlated with weather variability in both irrigated and non-irrigated trees. center dot Results The growth period lasted longer and the cumulative sum of daily changes increased by 130% in irrigated trees. Moreover, a similar correlation of tree water status with climatic variables was found in non-irrigated, with the exception of precipitation. center dot Conclusion Irrigation increased stone pine productivity in this xeric environment and reduced the correlations between daily stem diameter variations and local climatic variability.

Automated summary

The irrigation of adult stone pine trees growing in a xeric non-native habitat not only positively affected stem diameter growth, but also improved the trees' response to climatic variability. The study in Chile showed that irrigation increased productivity and reduced correlations between daily stem diameter variations and local climatic variability in stone pine trees.