About 50% (or 1840) of the threatened and near threatened species on the Red List are considered to have at least 20% of their occurrences in forests. The development of Norwegian forests and of the forestry sector is therefore of great importance to the conservation of biodiversity. This being said, it is interesting to note that there is no indication that the status of the red-listed species that are linked to forests has deteriorated between 2006 and 2010.
As part of the country's sustainable forest management approach many initiatives with a positive effect on the diversity of associated biodiversity components in forests have been undertaken. For example, the policy to increase the volume of standing and lying dead wood has contributed to securing the habitat for a number of associated biodiversity species. Around a third of the red- listed species in forests are linked to dead trees and an especially large diversity of insects and fungi (e.g. saprophytic fungi) live by degrading dead wood. Measurements show that the amount of dead wood in Norwegian forests is steadily increasing as a result of various important environmental measures that have been taken in forestry over the past twenty years. The National Forest Inventory estimates that the current volume of dead wood in Norway varies between 80 and 100 million m3. It also shows that the amount of dead wood is increasing by more than 3 million m3 per year. This could be of positive influence on the status of many red-listed species in forests.
27 For this section of the report information and comments were provided by Artsdatabanken, NIBIO, the Norwegian Institute for Nature Research (NINA), the Ministry of Agriculture and Food and the Ministry of Climate and Environment.
There are also examples of species that are actually associated with managed forests. For example, several bird species depend on spruce plantations in areas that were not naturally colonized by spruce.
Felling and the subsequent removal of trees inevitably change the structure and composition of forests, as well as the local climatic conditions, which in turn affects the habitat of forest associated biodiversity. However, Norway's sustainable forest management approach aims to keep such effects localized and limited. In recent years, action has been taken, inter alia, to avoid or customize logging in areas that are of particular importance to red-listed species. In addition, the felling of trees is managed in such a way that the country has forests of all dimensions and age classes (e.g. a large share of today's "older" forests were newly planted following felling, storm felling or fire). Statistics from the National Forest Inventory show a steadily increasing volume of trees in all dimensions and age classes for the main types of forest, spruce, pine and deciduous forests. Over the past ten years, the area of forests with trees of over 100 years old has increased between 5 to 10%.
Where selection felling has shifted to clear felling (which is when nearly all the trees in the felled area are removed), the density of forests has increased. This might have a local impact on red-listed species that have a preference for open forests, including certain lichen and insect species.
However, the shift towards clear felling is not the only reason for denser Norwegian forests, nor is this phenomenon only taking place at the local level.
Changing grazing patterns have also had an impact on forest associated biodiversity. Over the past 50 years there has been a significant decline in domestic livestock grazing in Norwegian forests, while grazing by wild ungulates (red deer, moose and roe deer) has increased. This new grazing regime, where leaf and twig eaters rather than grass eaters have become predominant, has changed the competitive relationships between species living on the forest floor. In addition, the rise in moose populations has enhanced pressure on the regeneration of deciduous trees, particular aspen (Populus tremula), rowan (Sorbus aucuparia) and goat willow (Salix caprea), which are important habitat providers for many red-listed species in coniferous forests. In some areas, the grazing pressure of wild ungulates on the ground vegetation may also affect the plant cover, as well as the occurrence and diversity of animals that live there. A study on the effect of moose grazing revealed the largest diversity of ground beetles where grazing pressure was moderate.
The building of roads, including the construction of (farm) roads for the transportation of timber, along with housing and commercial and industrial developments affects a small proportion of Norway’s forest area. At the same time, however, some of these newly constructed roads contribute to strengthening the use of renewable forest resources that are embedded in a sustainable forest management strategy.
Pollution is reported to be a threat for around 5 % of the threatened and near threatened species in forests. With respect to long-transported air pollution, the SO2-concentrations in precipitation have substantially decreased in recent years. Nitrogen inputs on the other hand are still high. In forests (not in agricultural habitats) this can be of negative influence on mycorrhizal fungi that are particularly sensitive to higher levels of nitrogen.
Little is known on the effects of climate change on forest associated biodiversity, which may explain why only around 1 % of the threatened and near threatened species in forests are reported to be threatened by climate change. However, the impacts of climate change on both forest trees and their associated biodiversity are likely to rise in the future due to the unstable onset of spring and the increasingly favorable conditions for pest species.
Species that have been introduced into Norway through human activity are reported to threaten only eight of the threatened and near threatened species in forests. However, in the absence of an exhaustive assessment of alien species in forest habitats, this figure could be underestimated.