24 January 2025 | Article

Healthy forests are messy 

January has been windy in northern Sweden, with yellow and orange weather warnings issued one after another. Many trees have fallen onto roads and power lines. Now that the storm has passed, it’s time for forest owners to inspect their land and assess the damage to their forests. 

In areas where the ground is frozen, the damage is usually limited. Trees that fall in such areas typically break off partway up the trunk, and it is mainly trees with root rot that are affected. However, if the ground had not been frozen, the damage would have been much greater, with even healthy trees being uprooted.

Forest Management Rules

According to forest management laws, forest owners must ensure that the amount of fresh, green windfallen trees does not exceed five cubic meters per hectare. In areas heavily affected by spruce bark beetles, the limit is even stricter—three cubic meters per hectare.

This means that forest owners who want to support biodiversity can leave a few windfallen trees per hectare. The exact number depends on the size and thickness of the trees, but generally, one or two trees per hectare can be left lying.

The Biological Value of "Mess"

Spruce trees with root rot that break during storms have low economic value but are highly valuable for biodiversity. Such trees often suffer from brown rot caused by cellulose-degrading fungi, such as the red belt fungus (klibbticka).

If these windfallen trees are left in the forest, they benefit many species. As fungi take over the decomposition process, they create an important habitat for other organisms. Many insects feed on fungi, including their hyphae (the thread-like structures of the fungi) and fruiting bodies. In this way, what might first seem like “mess” in the forest contributes to creating a rich and diverse ecosystem.

Photo: fightCOtwo

This perspective is part of fightCOtwo’s ongoing work on long-term conservation of Swedish boreal forests, integrating verified carbon sequestration, biodiversity outcomes, and documented collaboration with the reindeer herding community and the Sámi Indigenous people.