Tree rooting patterns and soil water relations of healthy and damaged stands of mature oak (Quercus robur L. and Quercus petraea (Matt.) Liebl.)

摘要: At three sites in northwestern Germany, which represent the centres of present oak damage, root distribution and biomass beneath healthy damaged trees mature pedunculate (Quercus robur L.; Neuenburg site) sessile (Q. petraea [Matt.] Liebl.; Lappwald Sprakensehl sites) were investigated, soil texture, bulk density, duration waterlogging periods water available mineral determined. For Sprakensehl, was related to leaf parameters determined a separate investigation. clayey hydromorphic Lappwald, measurements performed each one part site, differed number oaks with crown damage. In stand Neuenburg, clay content subsoil higher than stand, availability reduced especially dry periods. Compared density finest plus fine roots as well biomasses lower stand. With decreasing relative (actually relation at saturation state), decreased damaged, but not oaks. similar differences between found, had no effect on or roots. sandy site (Sprakensehl), drastically during period, predawn potentials both declined water. However, inferior ones respect biomass. It is concluded that, high subsoil, results prolonged waterlogging, sharp changes from drought periods, reason for oak. Thus, unfavourable relations are considered factor contributing damage sites,