I'm interested in methods of assessing the harmfulness of bark beetles in your countries. At what point they become economically significant insect species?
Prof. Jerzy Gutowski from Białowieża has published several papers and has much experience in this topic, I would suggest you to contact him through Research Gate or otherwise
You are right, Mr. Telnov - there is enough information. The causes and the damage caused by these insects are well known. What is the control in your countries at different levels of attack by bark beetles? What else unless cutting? Are you cutting alive trees to reduce the damages? In what range?