Effects of beech ( Fagus sylvatica), ash ( Fraxinus excelsior) and lime ( Tilia spec.) on soil chemical properties in a mixed deciduous forest

Aims We aimed to determine the influence of the distribution of different broadleaved tree species on soil chemical properties in a mature deciduous forest in Central Germany. Methods Triangles of three neighboring trees (tree clusters) that consisted of either one or two species of European beech (Fagus sylvatica L.), European ash (Fraxinus excelsior L.) or lime (Tilia cordata Mill. or Tilia platyphyllos Scop.) were selected and analyzed for their litterfall chemistry and chemical properties of the forest floor and mineral soil (0–10 cm and 10–20 cm). Results Base saturation, pH-value and the stock of exchangeable Mg2+ (0–10 cm) were highest under ash and lowest under beech. The proportion of exchangeable Al3+ was smallest under ash and highest under beech. The stock of exchangeable Mg2+ and Ca2+ correlated positively with the annual input of the respective nutrient from leaf litterfall. Ash leaf litterfall contained highest amounts of Mg and Ca. Beech leaf litterfall showed the highest C:N ratio and lignin:N ratio. Soil pH, stocks of organic C, total N and exchangeable Mg2+ and Ca2+ correlated positively with increasing proportions of ash leaf litter to total leaf litterfall. Conclusions Our results indicate that the abundance of ash in beech dominated forests on loess over limestone had a positive effect on soil chemical properties and reduced soil acidification. The inter- mixture and distribution of ash in beech-dominated stands resulted in an increase of the horizontal and vertical diversity of the soil habitat