Logging residue and cut stumps are increasingly used as a renewable energy source known as forest fuel. Forest fuel harvesting obviously reduces the volume of dead wood and is likely to alter the dead wood composition, but the magnitude of the change is not known. Such information is important for the evaluation of the effects of forest fuel harvesting on biodiversity because a large proportion of forest dwelling species are directly dependent on dead wood. We measured the volume and characteristics of all dead wood units with a minimum diameter of 2 cm and a minimum length of 20 cm on 10 forest-fuel harvested and 10 traditional (control) clear-cuts. The total volume of dead wood at forest fuel harvested and control clear-cuts was 26.0 and 42.3 m 3 /ha, respectively. The volumes were much greater than expected suggesting that the volume of dead wood on clear-cuts has been underestimated in previous studies. Forest fuel harvested clear-cuts had 42% less branches and 81% less cut stumps than control clear-cuts but there were no differences in the volume of logs and pieces of logs, snags or roots. The volume of fine woody debris was negatively affected by forest fuel harvesting. We conclude that fine woody debris and cut stumps form a considerable resource on clear-cuts that is reduced by forest fuel harvesting. These components of dead wood have potential to be of importance in managed forests and thus deserve more attention in future biodiversity studies.

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Biodiversity indicator species are needed for classifying biotopes and sites for conservation, and a number of methods have been developed for determining indicator species for this purpose. Nevertheless, in addition to site classification, there is sometimes a need to define an indicator species that indicates the occurrence of another species. For example, when a species of interest (target species) is difficult to detect or identify, a reliable indicator species can function as a tool that saves time and money. We derived a method that provides a quantitative measure of the indicator power (IP) of an indicator species for the target species or any species assemblage. We calculated the measure of IP from a presence-absence matrix that covered several sites. The method provided a list of indicator species, the presence of which reliably indicated the presence of another species (e.g., a threatened or rare species in a given area). The IP of the species was highest when the number of shared occurrences between the indicator species and the target species was high and, simultaneously, when the indicator species and the target species occurred separately in only a few cases. The IP was also positively influenced by the number of sites with no occurrences of either the indicator or the target species. Our method can also be used to quantify different types of species occurrence indications. We refer to these types as presence-presence, presence-absence, absence-presence, and absence-absence indications. To clarify the use of the method, we examined the situation with red-listed polypores in White-backed Woodpecker (Dendrocopos leucotos) habitats in Fennoscandia and found some suitable indicator species. Our method provides a new, objective way to evaluate the IP of an indicator species.

The cover and extent of boreal broadleaved forests have been decreasing due to modern forest management practices and fire suppression. As decomposers of woody material, polypores are ecologically important ecosystem engineers. The ecology and conservation biology of polypores have been studied intensively in boreal coniferous forests. However, only a few studies have focused on the species living on broadleaved trees. To increase knowledge on this species group we conducted polypore surveys in 27 broadleaved forests and 303 forest compartments (539 ha) on the southern boreal zone in Finland and measured dead wood and forest characteristics. We detected altogether 98 polypore species, of which 13 are red-listed in Finland. 60% of the recorded species are primarily associated with broadleaved trees. The number of species in a local community present in a broadleaved forest covered approximately 50 species, of which 30-40 were primarily associated with broadleaved trees. The size of the inventoried area explained 67% of the variation in the species richness, but unlike in previous studies conducted in coniferous forests, dead wood variables as well as forest structure had very limited power in explaining polypore species richness on forest stand level. The compartments occupied by red listed Protomerulius caryae had an especially high volume of living birch, but otherwise the occurrences of red-listed species could not be predicted based on the forest structure.

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