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Positive trend in forests but Nature Index values are still low


1.1 Norwegian ecosystems will achieve good status and deliver ecosystem services.


Ecological status and trends for the following major ecosystems: marine and coastal waters, rivers and lakes, wetlands, forest, mountains and cultural landscapes (see the Norwegian Nature Index and the Water Management Regulations)

Nature Index values for forest


Are we moving in the right direction? Published by the Norwegian Environment Agency

The state of biodiversity in forest ecosystems as measured by the Norwegian Nature Index has shown a weak positive trend since 1990. In 2014, the Nature Index value for forests for Norway as a whole was 0.37 (in this system, the reference state is given the value 1, and is defined to correspond to minimal disturbance from human activities).

The small numbers of old trees, low volume of standing and lying dead wood and low carnivore numbers in Norway's forests today go a long way towards explaining the low Nature Index values for forest. Dead wood and old trees are important habitats for many insects and fungi, and biodiversity is lower where these habitats are in short supply. On the other hand, index values for two other key indicators, bilberry ground cover and small rodent populations, are somewhat higher.

The improvement in the state of biodiversity in forest ecosystems since 1990 is explained by an increase in the quantity of dead wood and bilberry ground cover and also growing cervid populations in recent years. The trend over time clearly illustrates the slow ecological processes and pace of change in forest ecosystems.

In a forest in the reference state used for comparison in the Nature Index, human activities would have very little effect, but disturbance by natural incidents such as forest fire, windthrow and insect outbreaks and the subsequent succession processes would be found throughout forested areas. This has not been the case in most areas of Norwegian forest for many hundred years, because they have been used and altered by people over a very long period. Forestry is considered to be the most important pressure on Norwegian forests today. Other important pressures are infrastructure development (roads, power lines and buildings), nitrogen inputs and climate change.