Restoration of natural legacies of fire in European boreal forests: an experimental approach to the effects on wood-decaying fungi

Abstract

Effective fire suspension in Fennoscandian boreal forests has caused a number of species to become threatened. To compensate for the negative ecological impacts of fire elimination, prescribed burning of forests as a restoration method has been introduced recently. We studied the effects of controlled burning on assemblages of wood-decaying polypores (Basidiomycota), including red-listed species, in a large-scale field experiment in Finland. A total of 24 forest sites were included in the factorial study design with two factors: logging and burning. The presence of polypore fruiting bodies was documented 1 year before the treatments, and 1 and 4 years after the treatments. Over 11 000 observations of 104 species of polypores were made. Change in the fungal species composition due to logging and burning was clear after 4 years. At the species level, the responses to logging and fire varied depending on the species. Treatments increased fruiting of pioneer decayers; however, most red-listed species seemed to suffer. Thus, prescribed burning does not offer immediate benefits for most red-listed species. In unlogged forests, the restorative effects of fire are likely to be seen later as the death and decay processes of trees continue and provide more resources for polypores. Résumé :Plusieurs espèces sont menacées dans la forêt boréale de la Fennoscandie à cause de l'élimination effective des incendies. Pour compenser les impacts écologiques négatifs de l'élimination des incendies, le brûlage dirigé des forêts a été introduit comme mesure de restauration. Nous avons étudié les effets du brûlage dirigé sur les assemblages de polypores (Basidiomycètes) qui décomposent le bois, incluant les espèces sur la liste rouge, dans une expérience à grande échelle sur le terrain en Finlande. Un total de 24 stations forestières ont été incluses dans un plan factoriel comprenant deux facteurs : la coupe et le brûlage. La présence de fructifications de polypores a été notée un an avant les traitements, ainsi qu'un et quatre ans après les traitements. Plus de 11 000 observations de 104 espèces de polypores ont été réalisées. Le changement dans la composition des espèces fongiques dû à la coupe et au brûlage était clair après quatre ans. Les réactions à la coupe et au feu variaient selon l'espèce. Les traitements ont augmenté la fructification des décomposeurs pionniers, mais ont cependant semblé nuire à la plupart des espèces sur la liste rouge. Par conséquent, le brûlage dirigé n'offre pas de bénéfices immédiats pour la plupart des espèces sur la liste rouge. Dans les forêts non coupées, les effets du feu utilisé comme mesure de restauration ont des chances d'être observés plus tard, à mesure que les processus de mortalité et de décomposition des arbres se poursuivent et fournissent plus de ressources pour les polypores.[Traduit par la Rédaction]

Importance of natural disturbance for recovery of the rare polypore Antrodiella citrinella Niemelä & Ryvarden

“…The fungus Dichomitus squalens, although fairly common in some other parts of the world, is very rare in Finland. After experimental prescribed burning, it appears in high densities, even if the area has been logged before burning (Junninen et al 2008).…”

Biological degradation of torrefied wood and charcoal

“…Another white rotter, P. cinnabarinus, a rapid degrader of lignin, caused loss of carbon on both spruce and birch. Its natural occurrence in forest fire areas [37] makes it a viable degrader of stored torrefied wood as well as charcoal. Brown rotter G. sepiarium prefers coniferous wood, but caused carbon loss in both tree species.…”

“…Brown rotter G. sepiarium prefers coniferous wood, but caused carbon loss in both tree species. It is also found on forest fire areas [37]. It uses endoglucanases to degrade cellulose and hemicelluloses, but has also been reported to produce cellobiohydrolases that erode crystalline cellulose [38,39] and could therefore also utilize quite severely charred wood.…”

Effects of restoration fire on dead wood heterogeneity and availability in three <i>Pinus sylvestris</i> forests in Sweden

“…Several studies have evaluated the value of restoration fires as a conservation tool in Fennoscandian boreal forest (Vanha-Majamaa et al 2007;Junninen et al 2008;Olsson and Jonsson 2010). However, to our knowledge no previous studies have addressed the effects of restoration fire on the abundance and heterogeneity of dead wood (but see Covington and Sackett 1992;Stephens and Finney 2002;Knapp et al 2005;Stephens and Moghaddas 2005 for examples of studies on prescribed fires and their effects, among other things on fuel reduction, in boreal North America).…”