Red-listed wood-decaying fungi in natural and managed forests : A comparative study on forest structures and species composition in boreal forests

by Magnusson, Magnus

Many species are exclusively associated with the later decay stages of dead wood found in old natural forests. Today, modern forestry practices reduce the amount of dead wood available. As a consequence, many wood-associated species are declining. The main aim of the study was to assess whether the composition and diversity of wood-decaying fungi differ between natural and managed forests. Further aims were to assess differences between environmental variables such as stand age, human impact and forest type. Four natural and four managed forests in the boreal zone of Sweden were investigated to obtain information on the presence and abundance of selected red-listed species of wood-decaying fungi in a landscape perspective. The focal red-listed species were searched for in line transects in a mountainous area in the northwest of the county Jämtland. The species investigated are commonly accepted as indicator species of forests with old-growth conditions. The study shows that the abundance and number of the focal species were higher in natural than managed forests. The study further shows that species numbers and abundances were correlated with the volume of coarse woody debris (CWD), logs in later decay stages, spruce forests, forest age > 120 years, and a low degree of human impact. All these variables were also more common in natural forests compared to managed forests. The forest structures together with species composition and diversity give valuable information that is used for a detailed characterisation of the natural and managed forests in the region.