The spruce bark beetle, which damages our coniferous forests, is effectively controlled by the Swedish Forest Agency, which now uses satellite data.
An article from National Space Agency explains that using instruments on the ground and satellites in orbit, the EU's Copernicus Earth observation programme collects data to improve environmental monitoring, mitigate the effects of climate change and strengthen civil security measures.
Within the framework of the Copernicus Collaboration of Authorities, several Swedish authorities are co-operating and benefiting from satellite data. The Swedish Forest Agency is one of these partners and uses Sentinel-2 satellite data to manage the spruce bark beetle threat.
The spruce bark beetle, a harmful insect in our coniferous forests, measures only four millimetres. It is the only one of around 90 species of bark beetle that can kill a healthy spruce.
The insects primarily attack storm-felled spruce trees, but living spruce trees can also be affected, especially when the spruce bark beetle population is large compared to the spruce's ability to defend itself.
After the males arrive at the stressed trees and burrow into the bark, they use the spruce's resin to create a pheromone to attract more males. When the spruce finally abandons its resistance, the males call the females who then crawl into the newly formed mating chambers.
Each female then gnaws out once following the fibres of the spruce and lays eggs along it. The larvae eat their way out of the birth canal and pupate after 5-6 weeks. A week later, the new bark beetles hatch, staying under the bark to feed and for their shells to harden.
About eight to ten weeks after swarming, they leave the spruce in a dying state. In recent years, around seven million cubic metres of forest have been damaged annually by the spruce bark beetle, costing forest owners and Sweden billions of kronor.
In the past, physical inspection or drone surveillance was required to identify infested trees. But now the spruce bark beetle can be controlled using data from the Copernicus programme's satellites.
According to Anders Persson, GIS specialist at the Swedish Forest Agency, the Sentinel-2 satellite passes Sweden every five days and photographs the entire country from north to south. The images taken cover a width of 295 kilometres and a length of ten metres.
The images the Swedish Forest Agency receives from the European Space Agency (ESA) contain wavelengths that the human eye cannot perceive. In addition to the visible red, green and blue light, the images include ten additional channels, such as near infrared light. By combining near-infrared light with the red, the Swedish Forest Agency can calculate a vegetation index, which can be roughly considered a measure of forest vitality.
"Images from two different points in time are compared and a change analysis is created, where variations in the vegetation index are highlighted using a colour scale - from blue, through green to yellow. Blue indicates viable vegetation, while yellow can signal an attack by the spruce bark beetle," explains Anders Persson.
The Swedish Forest Agency has been using satellite data to control the spruce bark beetle for about a year and has developed infrastructure to effectively manage this information. From March to November, the Forest Agency makes the images available the day after they are taken.
"This allows forest owners to carry out these analyses themselves, provided they have the right technology. Previously, it was difficult to get an overview of spruce bark beetle infestations, so satellite data makes the process both faster and more cost-effective," adds Persson.
Facts Copernicus inter-agency co-operation:
Copernicus emphasises the need to meet user requirements. Sweden is therefore committed to exploring national needs in order to effectively promote them within the European Copernicus co-operation. Most Swedish authorities therefore co-operate within Copernicus. As Copernicus develops, the need for effective national coordination between those who will implement and use the programme increases. Successful collaboration between the authorities also means that Sweden can have broad representation on various committees, that satellite data is utilised more effectively and that the economic benefits of space activities increase.
