Smaller areas with high forest nature values are omitted from felling based on what is called environmental consideration. These can include, for example, forest groups containing dead wood, large old trees or protection zones along watercourses. Larger areas are saved in their entirety as so-called voluntary set-asides. This allows valuable structures, substrates and environments to coexist with sustainable forest management in the same forests in the future as well.

The purpose of nature value assessments is to enable us to decide whether forests should be managed with environmental consideration or set aside to ensure nature conservation, and whether nature conservation management is needed to preserve or enhance the nature values of the forest.

A nature value assessment involves assessing how high the nature value of a forest is by looking in terms of nature conservation at important structures and species and the history of the forest, and identifying biotopes that require the showing of special consideration.

Different forestry companies and forest owners use slightly different methods to make nature value assessments. Sveaskog uses a method developed in collaboration with the Swedish Forest Agency.

The method is clearly described in an instruction and everyone who works with nature value assessments at Sveaskog has been trained in the method. The method can be described as consisting of three parts: inventory, assessment and description.

Forest stands that are assessed as having high nature values according to the method are set aside as conservation forests.

How the method works

Inventory

A nature value assessment is based on collecting nature value data from a number of sample areas and then summarising this data to give a representative picture of the stand. The number of sample areas depends on the size of the stand, as well as on the diversity of the forest within the stand. The sample areas are evenly distributed throughout the stand and their locations are determined before the inventory is commenced. Sample areas are circular and have a radius of 18 metres. Within each sample area, the person doing the inventory notes the presence of different elements, structures and whether the sample area is a particularly valuable environment.

Among other things, the number of nature value trees, dead standing trees and dead trees lying on the ground are counted. Within each sample area, species findings and different characteristics that may indicate continuity or give a picture of the history of the stand are also noted. According to Sveaskog's nature value assessment method, the person performing the inventory must also follow a coding diagram to help assess whether the stand or part of the stand is a biotope that requires consideration.

The values of the sample area are summarised and an assessment is made of the sample area: does it have high nature values, no nature values or is it a borderline case? Information about the stand, such as the presence of particular conservation species, is also noted between sample areas.

Assessment

When all the sample areas have had an inventory performed, this provides an overview of whether or not the stand has high nature values. It may also be found that part of the stand has high nature values while the rest does not. In such cases the stand is split up.

The assessment of the nature values of the stand is made by weighing together the information that has already been collected. If the stand has been split up, an individual assessment is made for each part. Based on the data collected, different nature value ratings are allocated based on a range of parameters. The ratings form the basis for the final nature value assessment, but the whole is also taken into account.

Forest stands that are assessed as having high nature values according to the method are set aside as conservation forests. Stands that do not fulfil these criteria are classified as production forest.

Description

For those stands that are assessed as being conservation forests, labels such as woodland key-habitat, biotope requiring consideration or nature value site are applied. The final part of the nature value assessment involves stating the long-term and future objectives of the conservation forest, together with a description of any nature conservation management needed to achieve each objective. This means that management measures are also carried out in conservation forests, but they are always used solely to preserve or enhance the nature values of the stand.

In stands that, according to the nature value assessment, are production forests, general or enhanced environmental consideration is taken when felling. This means that, for example, deciduous trees, large groups of trees, large and old trees and dead wood are saved. This is done to ensure that in the future we have forests that are as diverse as possible in terms of age, deciduous trees and different habitats.

The nature value assessment and the nature values within the various sample areas form the basis for the assessment of how big the area to be given consideration should be and also which parts may be suitable for saving in order to give consideration.