Atmospheric and Structural Controls on Carbon and Water Relations in Mixed-Forest Stands of Beech and Oak

Abstract

The natural vegetation of central Europe is dominated by European beech (Fagus sylvatica) increasingly mixed with pedunculate oak (Quercus robur) in dry lowlands and sessile oak (Quercus petraea) in lower montane regions (Walter and Breckle 1994). Companion species are hornbeam (Carpinus betu-lus) and lime (Tilia platyphyllos, T. cordata). Since many tree species disappeared during the glacial periods, even natural deciduous forests in central Europe are relatively species-poor (Ellenberg 1982; Mayer 1984). Within broad-leaved species, forest management has concentrated on oak and beech for many years, even though the variety of species used for wood production is now slightly increasing. Today, additional benefits of forest functions like air and water quality, flux control (nitrogen, carbon), biodiversity and recreation are considered. More mixed-deciduous forests are being re-established, now reaching an area of 44% in Germany (Smaltschinski 1990; Krüger et al. 1994). Despite their increasing importance, comparably little information on the physiology and ecology of mixed stands is available. Ecological benefits expected from mixed-forest stands include higher structural diversity, higher physical stability, higher diversification in the use of resources, higher resistance to herbivory and pests, and more balanced response to environmental change (e.g., Cannel et al. 1992; Kelty et al. 1992; Larson 1992; Thomasius 1992; Pretzsch 2003).KeywordsLeaf Area IndexMixed StandSapwood AreaStand Basal AreaQuercus PetraeaThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.