Temporally resolved intra-annual wood density variations in European beech (Fagus sylvatica L.) as affected by climate and aspect

Abstract

We investigated the temporal variability of intra-annual wood density variations in European beech (Fagus sylvatica L.) in a valley in southwestern Germany. Samples were collected from 11 beech trees growing at north-west (NW) and south-west (SW) exposed slopes. High-frequency densitometry was used to obtain wood density profiles. We converted radial positions within these profiles to a seasonal time scale over automatic point dendrometer data for the period 2001-2006. Temporally resolved wood density data was analyzed both visually and statistically, using correlation analysis and multiple linear regressions. Water availability was found to be of major importance for wood formation. Further, our results suggest that climatic forcing of wood density is not necessarily restricted to the late growing season only, but that strong associations may exist during a major part of the growing season. Combining wood property data with point dendrometer measurements was demonstrated to be valuable for increasing the understanding on the effects of changing environmental conditions on wood formation.