Soil fungal and bacterial community structure in monocultures of fourteen tree species of the temperate zone

Knowledge about the effects of tree species on the soil environment is crucial for implementation of sustainable forest management. The aim of our study was thus to compare the effects of 14 tree species with contrasting traits and origin in Poland and/or Europe on fungal and bacterial diversity in soils. To reduce confounding factors such as differences in topography, microclimate, the age of the tree stand, the admixture of other tree species and soil type, we used a common garden experiment, comprising 14 tree species planted 50 years ago as monoculture plots. We examined soil microbial communities via metabarcoding of bacteria and fungi, including arbuscular mycorrhizal fungi, followed by Illumina sequencing. The highest fungal species richness was found under Acer pseudoplatanus, whereas Carpinus betulus and Quercus rubra were characterized by the lowest species richness. Acer pseudoplatanus and Tilia cordata were associated with the highest species richness of bacteria, followed by Acer platanoides. Fungal composition was mainly explained by the tree species identity, while bacterial composition was explained by soil chemical properties, namely pH and contents of exchangeable Ca, K and Mg. Interaction between tree species identity and soil chemical properties was also important. Tree species belonging to the same genus tended to harbor microbial communities with similar structures, while we did not observe a clear difference between broadleaf and coniferous trees, and between native and alien species. We suggest using admixtures of Acer spp. and T. cordata to improve soil microbial diversity in the process of afforestation of new areas and in restoration of degraded lands.

Automated summary

Understanding the effects of different tree species on soil microbial diversity is crucial for sustainable forest management. This study compared the effects of 14 tree species in Poland and Europe on fungal and bacterial diversity in soils. Results showed that Acer pseudoplatanus had the highest fungal species richness, while Carpinus betulus and Quercus rubra had the lowest. Tree species identity mainly influenced fungal composition, while soil chemical properties such as pH and exchangeable Ca, K and Mg influenced bacterial composition.