Bark beetle

Time and again, along the Rothaarsteig, you’ll see areas of forest that have completely died off. The trees there have strange patterns on their trunks. These patterns were caused by bark beetles. They live throughout the forests and attack only diseased trees. However, if there are a large number of trees of the same species in one area and they all become diseased at the same time, the bark beetle can multiply very quickly and in very large numbers. Forested areas with only one tree species are called monocultures. Along the Rothaarsteig, there are many such areas dominated by spruce. Here, the bark beetle has spread very rapidly in recent years because it found ideal living conditions. Many trees here became diseased after storms and due to extreme heat.  

How do bark beetles get into the trees? An adult beetle bores into the tree from the outside. It can do this quite easily with diseased trees that are too weak to produce sticky resin. The resin would have stopped the beetle.  

The bark beetles then reproduce beneath the Borke. The layer underneath is called the bast, and it serves as food for the beetle larvae. They eat their way through the many branching channels in the bast, which you can see on the infested trees. Gradually, they destroy the bast, through which the tree also transports water and nutrients from its roots to its crown. Then the tree dies. At the same time, thousands of new beetles emerge from the tree and infest neighboring trees.