Demonstration project Conservation of the common ash (FraxForFuture); joint project 5.2 FraxSilva: Evaluation of silvicultural systems - ecological principles, epidemiology and mixture

The leaf litter on the ground plays an important role in the development cycle of H. fraxineus because this is where the sexual phase of the fungus grows. The litter also changes with the composition of the tree species, which in turn could influence reproduction. Finally, this could also change the infection process. It can therefore be assumed that an enrichment of pure ash litter with litter of other tree species can have an influence on the reproduction of the fungus depending on the degree of mixing.

Based on this consideration, annual ash trees are planted in individual, self-contained greenhouses. This prevents the exchange of spores between the variants. The mineral soils of the greenhouses are covered with a defined amount of ash litter, to which the litter of copper beech(Fagus sylvatica), sycamore maple(Acer pseudoplatanus) and small-leaved lime(Tilia cordata) are added as common mixed tree species. By varying the litter proportions, it is possible to simulate different mixture proportions. In addition to a control variant with pure ash litter and a zero variant without any litter, each combination exists in three replicates. The infection pressure within the chambers is quantified using spore measurements.

The infection process of the fungus in the ash trees is monitored in high resolution over several years. Individual differences are described according to jointly developed keys.

In addition, the spread of spores of the fungus on individual old ash trees within a stand is also traced. The aim is to uncover patterns that have already been successfully investigated in a similar way for seed dispersal of different tree species.