Koli National Park, one of Finland’s most iconic landscapes, stands as a vivid example of the challenges posed by climate change to natural environments. Known for its breathtaking scenery and ecological significance, Koli attracts numerous visitors each year. However, the park is increasingly grappling with visible signs of forest damage, including dead trees, which are often a cause for concern among visitors.
“Dead trees cause concern among visitors. However, they are not removed because it is a nature reserve. Koli thus serves as a showcase for climate change to the public,” explains Olli-Pekka Tikkanen, University Lecturer at the School of Forest Sciences, University of Eastern Finland.
Tikkanen highlights that insect damage is a natural process in forests, with wind-damaged areas often providing habitats for pest insects. However, the dynamics of insect reproduction in Northern Europe are shifting due to climate change. Traditionally, the region’s cold climate limited the reproductive efficiency of pests like the European spruce bark beetle. Today, rising temperatures and changing forest conditions are exacerbating the problem.
The situation is compounded by the impact of drought on trees. Healthy spruce trees typically defend themselves by producing resin, which helps repel pest insects. Drought, however, stresses the trees and reduces their ability to produce this critical resin. “Even healthy trees are now at risk because drought causes them stress, leaving them defenceless,” Tikkanen adds.
Koli’s forest is particularly vulnerable to these changes. With its relatively old trees and thin soil, the area is highly susceptible to drought. As spruce trees age, their natural defenses weaken, making them more prone to insect infestations. Conversely, younger forests are generally better equipped to fend off pests. Recent years of dry, warm summers have worsened the problem, leading to increased damage caused by the European spruce bark beetle, especially in regions already prone to forest degradation.
The European spruce bark beetle, a highly efficient pest, is wreaking havoc not only in Koli but also in other areas such as the Puijo Nature Reserve in Kuopio. Its impact extends across southern Finland, where the beetle’s population is steadily growing due to favorable climatic conditions.
In response to the escalating problem, researchers at the University of Eastern Finland’s School of Forest Sciences are intensifying efforts to predict, identify, and prevent bark beetle damage. One innovative approach involves studying how damaged trees affect people’s experiences of nature. “Forest damage can be addressed early,” says Tikkanen.
Current recommendations for forest owners emphasize regular inspections, ideally every three weeks, to identify and address damage before it spreads. However, this process is labor-intensive and costly. To improve efficiency, researchers are leveraging advanced technologies such as drone-operated remote sensing and large-scale forest data modeling.
Using stand-level data provided by the Finnish Forest Centre, researchers can gain detailed insights into forest composition. This data includes information about tree species, age, volume, and soil type—whether mineral or peat. By integrating these findings with forest simulation tools, experts can predict how various forest management practices influence the risk of damage.
Finnish legislation also plays a role in monitoring and mitigating insect damage. Forest use notifications are mandatory for any felling activities, including those undertaken due to pest infestations. In spruce forests, the European spruce bark beetle is the primary culprit, and its prevalence is closely monitored across the country. This systematic tracking enables researchers to assess infestation patterns and develop effective management strategies.
Despite these efforts, the challenges are immense. Forests in regions like Koli and Puijo are not just ecological treasures but also vital components of Finland’s national heritage. The increasing frequency and severity of damage caused by pests like the spruce bark beetle underscore the urgent need for adaptive forest management practices.
Tikkanen emphasizes that addressing these issues requires a combination of scientific research, technological innovation, and public awareness. By understanding the interplay between climate change, forest health, and pest dynamics, Finland can develop strategies to protect its forests for future generations. For now, Koli stands as a reminder of both the resilience and vulnerability of nature in the face of a rapidly changing world.