There are many types of dead wood: standing up, lying on the ground, in bits, and burnt. In addition to this, dead wood comes in various forms depending on, for example, the species, size, how the tree died and the stage of decay. All manner of decayed wood is required to preserve forest biodiversity, because a quarter of species living in Finnish forests – that is, some 4,000 to 5,000 of them – are estimated to require decayed wood for nutrition, to live on and to multiply.
The care of commercial forests has progressed in leaps and bounds in recent decades: retention trees and the decayed wood formed by them have been identified as the key factor in that forest types are no longer becoming more endangered. Dead wood is increased in Tornator’s commercial forests by leaving large living and dead retention trees permanently in, and by making artificial stumps or cutting trees at the height of about two metres. Prescribed burning creates burnt wood – important for boreal forest ecosystems – which in time will develop into decayed wood. Plenty of decayed wood is created in conservation areas not in forestry use, in valuable habitats and in buffer zones near waterways. All these measures are beginning to show a positive impact in the National Forest Inventory measures done on the company’s forests.
This means that next to a quickly growing spruce thanks to effective and important forest management measures, there is room for a slowly decaying birch or an aspen worth couple of euros that have immense value in terms of biodiversity. Finnish commercial forests do not have enough decayed wood yet, but we have to bear in mind that it takes time for wood to decay and create a continuum, so it will take years until the measures taken today will show. But it is obvious that the volume of various types of decayed wood must be increased in forests.
Trees that have fallen as a result of a storm, for example, is an imminent threat to spruce stands because of European spruce bark beetles. This is why the Forest Damage Prevention Act (1087 of 2013) demands that the forest owner removes fallen trees with the bark still on as soon as possible. However, wood that has decayed slowly poses no such threat to forests, on the contrary, in fact: forest containing decayed wood is diverse and therefore a healthy and resilient ecosystem to fight against damages. Similarly, occasional windthrow and trees killed by insects are a normal part of forest ecosystems. A forest should not be too hygienic.
Dead tree is valuable also in terms of commercial use of forests, because a continuous presence of decayed wood keeps the forest healthy and enables continued sustainable forestry. A dead tree is not a sign of a poorly managed forest but a stamp of biodiversity. As a satisfied Tornator employee I can say that ensuring a sufficient amount of decayed wood is one of the targets in Tornator’s Biodiversity Program 2021–2030.
