The impact of soil aeration on oak decline in south-western Germany : Forest Ecosystem Restoration. Ecological and Economical Impacts of Restoration Processes in Secondary Coniferous Forests

2000

S. 92-98

26 Lit. Ang.

Unselbständiges Werk

200072879

In declining oak stands, symptoms of degeneration of the fine root system as well as deficiencies in the soil structure of the upper layer have been observed. In this study, we test the working hypothesis, that deficiencies in soil gas permeability reduce fine-root formation and by this way stress tolerance of the trees. At 35 oak stands (Quercus robur L. and Quercus petraea Liebl.) the top soil gas diffusivity, root density and oak vitality was assessed. Additionally at 6 oak stands the relation between top soil gas diffusivity, soil respiration and soil CO2 concentration was investigated. At the integration level of south western Germany it was shown that root density decreases significantly with decreasing soil gas permeability. Heavy damaged oak stands could be found only at sites suffering aeration deficiencies. Although we observed a decreased soil respiration in compacted soils, soil CO2 concentration there was up to three times higher. High soil CO2 concentrations indicate rather insufficient soil aeration than high biologic activity. Apparently insufficient soil aeration is a primary and triggering factor in the cause of oak decline.