The sites whose conservation is to be funded by the Foundation are selected based on the conservation principles of the Conservation Committee. Final conservation decisions also take into account the geographical distribution of the sites and the conservation resources available for each application round.
The conservation principles can be divided into primary conservation assessment principles and principles supporting the conservation assessment.
The older the trees are relative to the surrounding forests in the area, the greater the conservation value. Older forests have generally been undisturbed for a long time, and their conservation value in terms of species diversity develops faster than in younger forests.
Decaying wood is important for many forest species such as insects, fungi and birds. The amount of decaying wood in forests varies considerably, both naturally and due to the forest management history. In general, the age of forests increases as we move north, while the quantity of decaying wood decreases. The amount of decaying wood is relative to the situation in a certain area. In addition to the amount of decaying wood, its qualitative diversity increases conservation value.
Previous forest management affects the structure and development of a forest. Forests that are closer to their natural state because of lesser management often have more conservational value.
A site may have multiple habitats or forest structures that form a diverse combination. Diversity increases conservational value because it provides habitats for more species. It can increase a site’s conservational value even when the age of the tree stand or the amount of decaying wood is not particularly significant.
The diversity of tree species is a key factor determining the occurrence of different tree dependent species.
Forest canopy layers increase structural diversity, and the presence of different tree generations affects the amount of species present.
Particularly valuable habitats such as herb-rich forests and small waterbodies increase the site’s conservation value.
The connectivity of the site to other conservation or high biodiversity areas increases the effectiveness of conservation.
A larger cohesive area can be ecologically more valuable than a small or fragmented site. Due to this, the Foundation conserves areas of at least one hectare.
The presence of diverse and endangered species increases a site’s conservation value.
Other distinctive forests can also be proposed for conservation. Such exceptional sites include burnt forests, sites created as a result of significant disturbances and rare forest habitats.