Epsilon Archive for Student Projects

Abstract

Climate change has increased the frequency and intensity of droughts, negatively affecting growth and productivity of trees such as pedunculate oak (Quercus robur L.), which is an important species in Sweden from both economic and ecological perspectives. Although current abundance of the species is strongly reduced, predictions of the future distribution indicate northward expansion of its range under climate change scenarios.
In this study I quantified oak volume growth responses to drought in Southern Sweden, focusing on climatic drivers, sensitivity analysis, recovery dynamics and comparison of two methods assessing the growth response.
Oak growth was mainly driven by water availability, showing significant responses to Standardized Precipitation Evapotranspiration Index calculated over three-month period (SPEI3) in spring and early summer, while temperature effects were weak and inconsistent. Growth response varied among trees and sites, but oak showed relatively high resistance to water stress. Recovery of oak growth occurred typically within one year after the drought, showing high resilience of oak to climatic variability. Growth responses were consistent along the stem, indicating that growth was reduced uniformly at different stem heights.