The magazine Extrakt reports in a Article about a new research project at Lund University. The spruce bark beetle is a pest that can cause massive forest damage, comparable to storms or fires, and this damage is expected to increase in a warmer climate. In central Europe, large forests have already been wiped out, and pine trees are also affected. Researchers at Lund University are now leading a project to investigate whether there is a risk that pine trees could be attacked to a greater extent here in Sweden.
In 2022, the spruce bark beetle killed over five million cubic metres of forest in Sweden, and although it is almost always spruce that is attacked, there have been reports that pine trees have also been attacked by spruce bark beetles. This raises the question of whether pine trees may be at risk of major infestations in the future. The research project aims to investigate the bark beetle's choice of trees and what causes it to sometimes attack pine and whether we can expect more such attacks in the future.
Today, some forest owners choose to plant pine instead of spruce to avoid spruce bark beetle infestation. This may increase the proportion of pine in Swedish forests, which could potentially lead to the spruce bark beetle starting to attack pine to a greater extent. It is therefore important to understand the risks of pine infestation before it becomes a major problem.
The researchers will investigate, among other things, whether certain individuals of bark beetles prefer pine to spruce, and whether they favour specific pines. Previous studies have shown that pine trees can smell differently depending on the chemical substances in the tree. These differences in odour may be due to genetic differences between pines, opening up the possibility of developing new varieties of pine with a specific odour that can deter bark beetle attacks.
Another factor that may influence the success of spruce bark beetles on pine trees is the fungi with which they live in symbiosis. The fungi seem to be important for the spruce bark beetle, for example the larvae and the young bark beetles eat the fungi that grow in their tunnels in the trees. The fungi also break down many of the substances in the trees' resin and bark, which are the trees' chemical defences against the bark beetle.
Scientists do not yet know how well the fungi do on pine, and this may have a direct link to how successful the bark beetle can be on pine. If the fungi do not thrive on pine, it is likely that the bark beetle will not either. To better understand these risks and possible consequences, research is now being conducted in both laboratory and field settings.
