Marking an affected tree.
One of the main tasks for us here in Bialowieza is to help to monitor the spread of the the spruce bark beetle (Ips typographus) in the forest. This work involves walking, crawling and wading through the thick of the forest in a certain assigned area, finding spruce trees and checking whether they are currently infected with the bark beetle. It requires putting on long trousers, rain jacket and wellies against the annoying forces of mosquitos, ticks and sharp twigs. It is surprisingly tyring and we are always looking forward to our lunch break on some tree stump in the middle of it all.
Signs of beetle activity on a spruce tree
The way to recognize an infection is to look at the bottom and the lower branches of the tree as you will find fresh saw dust piled up from the destructiv work of the beetle. We will then mark the tree and store its position on our GPS device. At the end of the day the numbers are recorded for a given area.
Monitoring the spreading of infections and the long-term effect on the forest are important as discussion have been ongoing on how to deal with the problem for years. In the Bialowieza forest the Polish forest ministery and other intersted parties want to make money selling wood from the forest. They prefer the trees to be cut and removed creating the typical tidy managed forest with trees arranged in lines and no undergrowth or decaying wood. The national park scientists however where able to show that this does not reduce the infection rate or spreading of the beetle. In a natural healthy forest the beetles will mainly select weak trees whose defense system they can overcome. They will help to renew the spruce forest with stronger trees. Falling trees will also create open spaces allowing young trees or undergrowth to develop. Throughout the history of forestry there have been years of beetle outbreaks, followed by years of recovery and spreading of spruce trees. The decaying trees left in the forest on the other side create a new habitat for mushrooms, new plant life and other beetles. There can be as many as 300 species of beetles on a dead tree, compared to around 60 on life trees. The final stage of decomposition will create fertilizer for the forest – energy that is otherwise constantly removed from the system if trees are taken out (dead or alive).
Natural decay and re-use of the tree’s energy
Facts aside, as mentioned before, walking through this kind of forest is a whole different experience and very exciting and relaxing at the same time. We constantly discover new mushrooms, look for frogs hoping around our feet, and hope for another sighting of birds, deer or bisons. Or we just stand there listening for any sounds and enjoy the fallen trees overgrown with mosses and ferns – in the natural forest with bark beetles.
Sources: Bialowieza National Park, Peter Wohlleben: Das geheime Leben der Baeume, featured image: Udo Schmidt/media wiki