Many forests Europe-wide are growing on nutrient-imbalanced acid soils, and are often composed of monocultures of adapted tree species that further amplify this oligotrophic regime. But study of palynological records and relict forests suggests that even on the poorest sands a rich, more productive alternative stable state, dominated by rich-litter tree species exists. From an evolutionary point of view, rich-litter is a more recent functional trait supporting fast nutrient turnover, earthworm bioturbation and mull humus. Research in common gardens has shown the potential of rich-litter species to maintain or restore resilient mesotrophic systems. But restoration is not straightforward: oligotrophic system interactions induce and maintain conditions that are hostile for rich-litter species. But restoration is hampered by the conditions of the oligotrophic system, which are hostile for rich-litter species. Successful large-scale restoration therefore implies deeper understanding of the factors underlying the attractor behavior of the oligotrophic system, which may be soil type and context dependent. As a result, integrated soil restoration combines actions supporting the introduction of rich-litter species, e.g. fertilization with rock dust, inoculation of earthworms, or introduction of accompanying shrub and herb species. This perspective paves the way for large-scale admixture of rich-litter species, from the fundamental research on litter decomposition and soil effects of mixtures, over the conceptual framework of rich-litter species and alternative stable states in forest soils, to the first results of restoration management experiments. It concludes with some considerations on the validity of this new concept in other continents.
No datasets are available for this submission.