Results – NBID43

The results showed that nature reserves had higher volumes of deadwood (Figure 1.) As well as higher variation of diameter classes and decay stages of the deadwood comapred to the production forests (Figure 2.). Nature reserves also had more observations of indicator species and red-listed species comapred to production forests (Figure 3.). The retention areas did not differ from the rest of the production forests in regard of deadwood volume or species observations.

Figure 1. Average deadwood volume in the different forests stand age groups. Grey bars are the deadwood volume in the retention areas while black bars are the volume in sample plots.

Figure 2. Decay stages on diameter classes in forest stand age groups.

Figure 3. Species richness in forests stand age groups.

With GLM and pairwise comparison it was shown that nature reserves often had a significant difference compared to production forests regarding species abundance and species richness (Figure 4;Figure 5). It was only for trivial species richness where no signficant difference could be found between the production forests and the nature reserves.

Figure 4. Species abundance for the different species groups in relation to forest category. Different letters signify a statistical difference based on pairwise comparisons using estimated means.

Figure 5. Species richness for the different species groups in relation to forest category. Different letters signify a statistical difference based on pairwise comparisons using estimated means.

The species composition was significantly explained by forest age category (R2= 0.51, p <0.001). The composition in nature reserves were separated from production forests (Figure 6.) and separated from each other based on pair-wise tests. Within production forests, clear-cuts stand out, while remaining categories were more intermixed.