Stora Enso – Drone pilots scanned thousands of trees: insect damages identified from the air

Stora Enso’s drone research used a drone and a multispectral camera to detect insect damages in Finnish forests. The image interpretation application was able to identify trees where spruce bark beetles nestled. The new forest health data can be used for example to plan forest management, timely silvicultural work and harvesting.

The spruce bark beetle, which damages spruces in particular, is estimated to become more common in the northern forests as the climate warms. Stora Enso Forest division’s drone was able to detect spruce bark beetle exposure much faster and more efficiently than the human eye. Research flights were conducted in in South Karelia, Finland in the vicinity of Lappeenranta in the summer of 2019, and the research results were recently finalised.

The spruce bark beetle prevents the normal flow of water from tree’s root system to the top of the spruce, which causes the tree to die upright before long. A multispectral camera connected to the drone identified the trees whose fluid circulation was disturbed. In the image, the exposed trees appeared in different colors than the healthy trees. This enables the observation of spruce bark beetle damage even in a large forest area, says forest specialist Saana Pulkkinen, from Stora Enso Forest division, who did her thesis as part of the research.

The study showed that the observation of spruce bark beetle exposure made by drones and the image interpretation application was reliable. It also turned out that the larger the tree in question, the easier it was to detect the exposure. In addition, the image interpretation application was programmed to identify spruces from the other tree species: identification was 97% correct. The findings of the application were further confirmed by a field trip. From the point of view of image interpretation, a cloudy weather was the best for the flights.

This was still research work and testing, but we can already now rely on our image interpretation application when it identifies an unhealthy or damaged tree. At some points, the application was still cautious in its interpretations, but the situation will improve as we get more data on the forests that have been photographed. Based on the research results, the health classification of trees was 86% correct, Pulkkinen states.

Drone research is part of a bigger development stream that we call precision forestry. Precision forestry will offer new opportunities to monitoring forest, management decisions optimization and increasing the value for forest owners and the industry, says Mikko Juhola SVP, Innovation & Development, Stora Enso Forest division.

In addition to Finland, forest research flights and image interpretation have been performed in Sweden and the Czech Republic. Health information on thousands of conifers has been accumulated on flights. Stora Enso’s drone pilots have already scanned hundreds of hectares of forest, and more and more forest data is being accumulated. Descriptions are always made with the permission of the forest owner.

Cooperation between our various forest units will ultimately benefit forest owners not only in Finland, but also in other countries where we operate. As a first step, we intend to utilize image interpretation data to locate spruce bark beetle damage. Going forward, data accumulated from the forest can also be used in forest plans and inventories. We will continue development work so that in the future we can provide drone scanning as a service to forest owners. Already now, some of our forest experts use the drone in their own work, for example in seedling monitoring, Mikko Juhola states.

The new Forest division, which started operations in the beginning of 2020, includes Stora Enso’s Swedish forest assets and the 41% share of Tornator with the majority of its forest assets located in Finland. The division also includes wood supply operations in Finland, Sweden, Russia and the Baltic countries. We create value to our customers and private forest owners with competitive wood supply, sustainable forest management and innovation. As a major player in the bioeconomy, access to wood is critical for Stora Enso. Today, Stora Enso is one of the biggest private forest owners and wood supply organizations in the world.

drone pilot

Stora Enso’s forest expert Saana Pulkkinen