Total protection can only secure and preserve a certain number of habitats of rare species in any locality.
Therefore silvicultural management is essentially required to maintain large-scale biodiversity in multifunctional production forests (Parviainen, 1998). This includes a large part of the forested areas outside the actually protected area. In most European countries this means at least 80–90% of the forested area. In some western and southern European countries (e.g. Ireland and Portugal) favourable site conditions enable efficient wood production in intensive
tree plantations. But in the countries of the boreal and cool temperate zones of Central and Northern Europe, sustainable forestry involves naturalistic silvicultural management
over large areas. The chosen concept of silviculture also determines the amount of those forested areas which remain completely outside commercial forestry and which are crucial refuges to ensure the survival of living vulnerable or rare organisms. The time-tested and verified hypothesis is that the closer to nature forestry activities are in multifunctional production forests, the less need there will be for total forest protection. The question is, how to balance the ratio between totally protected areas and managed forests.
Endangered species are seen as indicators of change in the forest ecosystem. Changes in the number of endangered species act as alarm signals when forest quality declines and its species spectrum impoverished due to unsuitable silvicultural practices. A similar indicator of forest status is the increase in environmental strain. Both the number of endangered species and the environmental strain have to be continuously monitored, and critical limits should be explored and defined wherever possible.