Since year 2000 birch caterpillars have attacked 1/3 of birch forests in northern Norway and many of the attacked trees will die. The caterpillars is still moving east, and have destroyed forests also in the municipality of Sør-Varanger, bordering to Russia.
Researcher and ecologist Snorre Hagen at the University in Tromsø, says to NRK that the birch caterpillar attack on forests in northern Norway is the largest ecosystem change in Norway in modern history. Several thousand square kilometres of birch forests have been totally stripped of green leaves by these small caterpillars, and nothing seems to stop their spreading. When the caterpillar is finished eating all the leaves, it starts consuming the under shrub.
Hagen believes many of the birches which have been attacked by the caterpillar also will die within the next years to come. When the attack started in 2000 the researcher thought it would last for 4 or 5 years. Now it has lasted for eight years, and it doesn’t seem to stop yet. Instead the attack has spread to an even wider territory, both to the east and west.
There are a lot of speculations to whether the extent of the attack is due to climate change. Hagen says that there are many indications that warmer climate in the north the last 10 years has had strong impact on the caterpillar attack.