Drought sensitivity of beech on a shallow chalk soil in northeastern Germany – a comparative study

Abstract

Background We compare the climate sensitivity of European beech (Fagus sylvatica L.) in two forest nature reserves in northeastern Germany. The one reserve, Schlossberg, is characterized by shallow chalk soils, whereas in the other reserve, Eldena, soils are deeper and more developed. Little is known about the drought sensitivity of beech on shallow chalk soils. Methods We collected increment cores at both research sites and established climate-growth relationships. Inter-tree variability was assessed by employing linear mixed-effect models. Results We expected to find distinctively higher drought sensitivity at Schlossberg due to limited water availability, but find only marginal differences in growth responses. At both sites, drought is the major climatic factor driving tree growth. Adaptations in tree architecture and an underestimation of the water holding capacity of shallow chalk soils are discussed as possible reasons for not finding more distinct climate responses. In analyzing climate-growth relationships, we specifically focused on growth responses of individual trees but observed only low inter-tree variability at both sites. Evident is a shift in climate response patterns from the first to the second half of the twentieth century with previous-year drought conditions becoming more important than current-year drought. This shift is discussed in relation to a warming trend over that same period, as well as possible trends in masting behavior of beech. Conclusion The investigated beech trees on the shallow chalk soil are only slightly more drought sensitive than beech trees on the reference site with deeper and more developed soils.

Keywords

• Climate-growth relationships
• Dendroecology
• Inter-tree variability
• Temporal stability
• Drought stress