Authors: Ramberg, Ellinor; Berglund , Håkan ;Penttilä, Reijo ;Strengbom , Joachim ;Jönsson , Mari ;

Intensive management of boreal forests has resulted in even-aged stands with little dead wood and few natural disturbances such as fire. Since dead wood, both burned and unburned, provides critical habitat for many threatened wood-inhabiting species there is a need for restoration. Here, we report the long-term effects of prescribed fire and coarse woody debris (CWD) additions, on polypore community diversity in spruce dominated boreal forests in Finland. The experiment has a factorial design (n=3) including three levels of created CWD (5, 30 and 60 m3 ha-1) crossed with fire or no fire. In 2018, 16 years after the initiation, we inventoried polypores on 20 logs per stand. We found that overall polypore community composition differed between burned and unburned stands. However, only red-listed species abundances and richness were positively affected by prescribed fire. We found no effects of CWD additions. We concluded that the long-term effects of fire for threatened polypore communities are beneficial. Additionally, our results suggest that although addition of CWD does not influence species diversity per dead wood item, fire does. This demonstrates that fire, besides the well-known effect of increasing habitat amount, may also favour red-listed polypores by changed habitat quality and continuity.