Northern forest

Long-term biodiversity indicators monitor developments in Northern forests

Stora Enso monitors biodiversity in the Nordics with two sets of indicators: biodiversity impact indicators in harvesting sites and long-term biodiversity indicators to follow developments across the forest landscape. For the time being, the long-term indicators apply to Stora Enso’s own forests in Sweden and are steps on our way to reaching a net positive impact on biodiversity.

Based on science, the goals vary depending on each indicator and forest type. Although their development is slow, the long-term indicators are reported on this page annually. We also continuously review our goals and assess new indicators and actions based on latest research and knowledge.


 Indcator  2023
 Share of broadleaved forests 2.3%
 Volume of all deadwood  8.5 m3 / ha
 Number of nature value trees  0.8 trees / ha
 Old forest distribution  78%
 Share of voluntary set-asides  10%

Last indicator update: December 2023

Birches in summer forest

Share of broadleaved forests


Target 2050: 5%

Broadleaved trees – such as downy birch, silver birch, aspen, and rowan – have been decreasing in Northern forests as a result of forest management practices in the past. Our goal is to increase the share of broadleaf-dominated forests on productive Stora Enso land to 5% by 2050. A forest is considered broadleaf-dominated when broadleaves make up more than 50% of the tree species in the forest.

To reach this goal, we plant silver birch in pure and mixed stands as well as promote birch and other broadleaves when tending and thinning forests. We monitor broadleaved trees with data from remote sensing and field inventories.

Why is it important?

Increasing the number of broadleaved trees will increase structural variation in forests and thus also biodiversity. Broadleaf-dominated stands form habitats for a wide range of species, especially many threatened birds and insects. For instance, the white-backed woodpecker prefers broadleaf-rich forests, and to maintain that habitat, it is important to constantly remove spruce that regenerates naturally on the forest floor. When such habitats are maintained with active forest management, it creates suitable habitats where many other rare species than the woodpecker may thrive as well.

Many species can live off several different tree species, but there are also various insects, fungi and lichen that need a specific tree species as food or home. This means that we need more variation in our landscapes to provide habitats for the widest range of organisms.

Deadwood on the ground

Volume of all deadwood


8.5 m3 / ha
Target: under development

Deadwood of different tree species and different stages of decomposition is fundamental for many rare species, but there is a lack of deadwood in today’s productive forests. As such, increasing deadwood volumes is one of the most effective measures to enhance biodiversity, and we are looking into new ways of managing deadwood in our forests to increase the amount.

Our long-term indicator reports the average volume of all deadwood, both standing and on the ground, across our productive forests. The data is derived from Swedish National Forest Inventory plots located on our land and calculations with SLU (Swedish University of Agricultural Sciences).

Our intention is to develop this indicator and also set a target for how much deadwood there should be and where in the forest landscape it should be located. When harvesting, our standard practice is to preserve deadwood and create high stumps, but we are also putting increased focus on exploring how and where to create new deadwood to have the optimal benefits for biodiversity. This requires complex development work, integrating deadwood and species data with modelling capabilities.

Why is it important?

A significant number of red-listed species in boreal forests depend on deadwood, and as there is a lack of deadwood in commercially managed forests compared to natural ones, the species dependent on that deadwood have also become rarer. Traditionally in commercial forestry, deadwood was removed from the forest to use it as firewood, decrease the risk of pest outbreaks (like spruce bark beetle), and make the forest easier to manage. Since the 1990s, more focus has been put on preserving and increasing deadwood thanks to new management practices and certifications.

Deadwood on the ground provides a vital habitat and cover for a multitude of species, especially many insects, whereas some birds like to make their home in standing deadwood. Decomposition stage and placement of deadwood are important: for instance, certain species prefer standing deadwood caused by fire, some prefer deadwood in open areas whereas others thrive on deadwood in moist and shadowy environments.

Tree in a protected forest

Number of nature value trees


0.8 trees / ha
Target: continuous increase

Nature value trees have deviant characteristics that make them especially valuable in their environment. For instance, they can be particularly rough and often significantly older than the other trees in the stand. Currently, we have an average of 0.8 nature value trees per hectare in our productive forests, meaning that we have approximately 941,000 such trees in total on our land.

We identify nature value trees in nature value assessments before harvesting and monitor them also with data from field inventories by external parties. The latest inventory was done in 2021.

Our aim is to continuously increase the number of nature value trees. In harvesting, we always leave at least 10 retention trees per hectare and prioritise trees with nature values. If there are none, we leave 10 trees to develop nature values in the future. Future nature value trees are also created through veteranisation of living trees, which is a way to damage trees to make them develop specific characteristics.

Why is it important?

What makes nature value trees so valuable is that they display structural anomalies, such as thick and twisted branches, ageing bark, cavities, or nests. They are important as microhabitats for many rare species – for instance birds and insects that inhabit old-growth trees. In addition, they may have other values that stem from the forest's history or represent a tree species that is of particular importance in the landscape.

In addition to current nature value assessments and field inventories, we hope to harness also different remote sensing methods to monitor nature value trees in the future. As we increase our knowledge of the trees we have, we can also make sure that the nature value trees are distributed more optimally in the future than they are today to have the greatest possible positive biodiversity impact. 


Old forest and deadwood

Old forest distribution


Target 2050: 100% (old forests in all ecological landscapes)

Old forests form exceptionally rich habitats, and our goal is to have old forests distributed so that they constitute at least 2% of the forest area in all (100%) of the ecological landscapes on our land. We have 63 ecological landscapes, and currently 49 of them have 2% or more of old forests: this means that in 78% of the landscapes, we have achieved the target. 

An ecological landscape is an area that is defined by particular characteristics in that area, such as certain forest and soil types, forestry history, or river systems. For instance, a forest with a history of recurring forest fires forms one type of an ecological landscape. The share of old forests varies greatly: in some ecological landscapes on our land more than 25% of the forest area is covered by old forest while in others it is only 0.5%. On average, we have more than 5% of old forests across our holdings.

We define old forests as forests that are over 140 years old, including both old managed forests as well as old-growth forests (old forests with high nature values and no apparent management history). We increase the old forest distribution by letting younger stands grow without harvesting them. We never harvest forests with old-growth characteristics or other high biodiversity values.

Why is it important?

Old forests, and especially old trees and deadwood within them, are important for biodiversity, because they have reached a late successional stage. Thanks to this, they provide habitats for many rare species that have become vulnerable, owing to the relative loss of old forests across landscapes due to intensive forestry.

Many of these species require very particular environments that take long to develop: for instance, some fungi can only live on long-decomposed deadwood underneath closed tree canopies. Hence it is important that we have old forests distributed across our forest holdings to support the diverse needs of various organisms.


Bird sitting in a nest

Share of voluntary set-asides


Target: 10%

Set-asides are forest areas that have been voluntarily protected and set aside from commercial forestry. Set-asides can be managed to enhance biodiversity values actively or left unmanaged to develop naturally, depending on their characteristics. We have assessed the FSC certification target of 10% to be an apt share of voluntary set-asides in our forests. Of these 10%, at least half should be prioritised due to their nature values and half due to nature or social values.

In addition to the voluntary set-asides, our lands contain also other environments that have been set aside from commercial forestry and infrastructure development due to various reasons. In total, all such areas comprise 30% of our land: this share consists of both productive and non-productive forestland.

Why is it important?

Voluntary set-asides are important environments for preserving habitat features that are vital for rare species. This can be done by leaving these elements to develop naturally or by managing them to maintain the key features over time. For instance, Stora Enso has set aside areas to promote sunny and sandy habitats for the endangered sand lizard (Lacerta agilis).

The biodiversity indicator data is collected from own forest land: in Sweden, Stora Enso owns 1.4 million hectares of land out of which 1.1 million hectares is forest. Data sources vary depending on the indicators, but common methods include remote sensing and field inventories. Data collection for each indicator is explained in more detail for that indicator.

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