The role of Swedish mountain birch forests in preserving insects and fungi

In northern Sweden, forestry has greatly reduced the amount of older forests with a large proportion of deciduous trees. In addition, deciduous trees of all ages have been combated both chemically and through selective felling such as clearing and thinning. As a result, many species associated with dead deciduous wood have declined and some have disappeared from large areas. However, mountain birch forests are still unaffected by industrial forestry and cover large areas.

– Mountain birch forests have plenty of dead deciduous wood, but very little is known about the organisms that live in this wood. The cold environment certainly means that some species are missing, but we don't know for sure which ones these are, says Mats Dynesius, researcher at the Swedish University of Agricultural Sciences (SLU).

Species composition is being studied

The project compares the composition of leaf litter-dwelling species in a number of mountain birch forests with other forests in northern Sweden located at lower altitudes. The focus is primarily on beetles and fungi. The insects are caught in various types of traps and the fungi are studied by taking wood samples for DNA analysis to determine which species are present in the wood.

The researchers will also compile distribution areas and ecological characteristics for all northern Swedish species of deciduous wood-dwelling beetles and fungi.

– We want to know which of these species are missing or rare in mountain birch forests and should be prioritised in nature conservation work in lower-lying forests, says Mats Dynesius.

The researchers also want to try to predict which lowland species may spread to mountain birch forests during the ongoing climate warming. In addition, they will analyse the information on dead wood in mountain birch forests that the National Forest Inventory has recently begun to collect.

– We want to use the knowledge we gain to provide well-founded advice on how we should design nature conservation measures in lower-lying forests to primarily benefit the deciduous species that cannot cope with the cold climate in mountain birch forests, says Mats Dynesius.

The fieldwork is being carried out in forests owned by the National Property Board and the forestry companies SCA and Holmen.