New information relieves fears of links between conservation sites and bark beetle damage
Damage by the spruce bark beetle on nature conservation areas is not a significant danger to commercial forests, says a study by Natural Resources Institute Finland.
No fellings should be undertaken on nature conservation areas to combat spruce bark beetle damage, for the risk of the beetle spreading to surrounding commercial forests is almost non-existent. This is shown by the recent study by Natural Resources Institute Finland (Luke).
’We could chop down all of the Koli National Park, and that still wouldn’t reduce the risk to nearby forests from the spruce bark beetle,’ says Markus Melin, Research Manager at Natural Resources Institute Finland, to forest.fi.
The park in question extends over 30 square kilometres.
Luke investigated cases where the government has paid compensations to forest owners because of damage spreading from conservation areas. At the same time, it also studied all fellings due to spruce bark beetle damage in relation to the locations of conservation areas.
Over a period of ten years, the number of cases where compensation had been paid amounted to just seven. In terms of timber volume, the total amount compensated for was about 160 cubic metres.
’In 2023, for instance, the National Forest Inventory detected damage by the spruce bark beetle on more than 60,000 hectares in all. This means that the share of damage spread from nature conservation areas is extremely small,’ Markus Melin explains.
In the same way, felling operations caused by insect damage near conservation areas, as reported to the Finnish Forest Centre, are no more frequent than in other areas.
Luke also reports that in other parts of Europe, preventing spruce bark beetle damage on a larger scale (on a landscape level) through fellings has not been successful.
Serious mistakes in Germany
The risk and volume of spruce bark beetle damage in Finland have increased in Finland in the 2020s, but at least so far, they are small in comparison to those seen in the spruce forests in Germany and the Czech Republic.
According to Melin, the most extensive damage in Germany has been seen in areas that have been planted with spruce even though it had not grown there previously. Moreover, the seedlings used in the damaged areas came from seeds not adapted to the climate of the growing site.
’When the trees were hit by drought, they were unable to defend themselves against the beetles. This should serve as a warning example for us. You mustn’t create spruce-dominated forests in areas where they don’t thrive naturally. Forests like this are more susceptible to damage,’ Melin says.
In Finland, the spread of damage by the spruce bark beetle has remained relatively local. Extensive, landscape-level damage as seen in Central Europe cannot yet be seen in Finnish forests. The main reason why Finnish forests are faring better is the colder climate.
’In Czech and Germany, the active season of the spruce bark beetle begins as early as in March, and continues until November. In Finland the season is only half as long,’ says Melin.
The situation in Finland is expected to get worse with global warming.
Fellings in conservation areas are detrimental
If it is decided to combat the beetle by fellings in nature conservation areas, most of the damaged trees should be removed. That, however, would be detrimental to biodiversity.
’From the biodiversity perspective the beetle does not cause damage, even if that’s how it looks to us humans. The trees killed by the spruce bark beetle are a source of deadwood, and that provides a living environment for thousands of species from a range of different types of organisms,’ Melin points out.
Once you see dead trees in a forest, removing them is like closing the gate after your horse has bolted.
’This is probably the greatest misconception. Seeing a lot of dead trees creates the image that something damaging is taking place and the damage is spreading. In actual fact, the spruce bark beetles will have left the area long since,’ Melin says.
Melin goes on to say that instead of conservation areas, there are spots presenting a higher risk for damage by the spruce bark beetle. According to the Finnish Forest Centre, things that increase the risk of bark beetle damage include trees felled by storms, the Heterobasidion fungus, previous insect damage, dead spruces, boundary zones, hillside stands and drought.
According to Luke, studies made in Europe show that pheromone traps do not prevent the spread of the spruce bark beetle, even if used extensively.
Read more: Natural enemies may prevent damage by spruce bark beetle – researcher explains how
