Biodiversity involves a complex interplay between many different species in different natural habitats. Holmen works hard to ensure that all the species that live in the forest can continue to do so. Different types of forest habitat need to be nurtured in order to preserve biodiversity. A total of around 20 per cent of Holmen's forest land is used for nature conservation purposes. This includes productive forest voluntarily set aside, unproductive forest land and environmental consideration in the managed forest.
|Holmen forests in 2016
|Total land acreage
||1 275 000 ha
|Total forest land acreage1)
||1 153 000 ha
|- of which nature conservation areas
||187 000 ha
|Productive forest land 2)
||1 042 000 ha
|Total volume of wood,
productive forest land
120 million m3 growing stock,
solid over bark
Analysis conducted by the Swedish National Forest Inventory, according to the international definition of forest land: Land with an area of more than 0.5 hectares, a tree canopy cover of more than 10 per cent and trees with a minimum height of 5 metres at maturity.
Forest land that on average can produce 1 m3 growing stock, solid over bark per hectare and year (on average during the growth period of the forest stand).
Part of Holmen's productive forest is used exclusively for nature conservation. These areas are carefully chosen for their nature conservation potential and often contain a wealth of natural assets. The set-aside areas of forest are spread across Holmen's forest holdings, providing habitats that vary greatly in terms of content, size and composition. The goal, however, is for the areas set aside for nature conservation purposes to remain viable over the long term, which makes it undesirable to set aside areas on too small a scale.
Some of the set-aside areas are left entirely untouched, while others have to be managed to retain the natural assets that are the reason why the forest has been set aside. Without targeted nature conservation felling broadleaf forest, for example, risks being outcompeted by spruce. Judicious felling can also be used to increase the quantity of dead wood, which is often in short supply in the forests.
There is a process under way to assess the conservation benefits of various methods aimed at promoting biodiversity. Holmen is, for example, involved in a major research project run by Future Forests which involves testing a range of methods in 30 set-aside areas. These measures are being monitored by researchers at the Swedish University of Agricultural Sciences (SLU).
Unproductive forest land
Unproductive forest land is forest where the trees grow extremely slowly due to a lack of nutrients or water. Unproductive forest land can be divided into two categories: bogs and rocky areas. There is often a high proportion of old, slow-growing and dead trees, which are important for a large number of species. Around 2 per cent of forest-dwelling species have their main habitat in unproductive forest land. No forestry is undertaken on unproductive land which, coupled with the set-aside forest, can create large, beautiful and richly varied areas.
Environmental consideration in managed forests
Forest-dwelling species are dependent on forest habitats and structures for their survival. For example, over half of all forest-dwelling species depend on mature broadleaved trees and large living, dying and dead trees. In order to create the right conditions for these species, Holmen protects nature conservation trees and conservation-promoting trees, while also preserving all dead trees in the managed forests. Nature conservation trees include large aspens, broadleaved trees north of the Dalälven river and trees that are unusually large or old or in some other way different from the norm. In cases where there are no nature conservation trees growing, conservation-promoting trees are instead left in order to improve the natural assets of the site over the long term. During general clearing and regeneration felling, high stumps are created from living trees in addition to the trees that died naturally.
Holmen also creates valuable buffer zones around unproductive forest, coastlines, lakes, water courses and agricultural land. These support a wealth of species, since the habitat varies in terms of light conditions, soil type and humidity, and because the flora and fauna of the forests is mixed with those associated with the bogs, water or open landscape.
This, coupled with the set-aside areas and unproductive forest land, creates a band of habitats for different species across the whole forest landscape.
* Trees that have died less than a year ago and that may be a breeding ground for pests, such as the pine weevil, are removed to prevent these pests massively increasing in number and becoming a danger to living forest.