bark wood beetle pest ips typographus infestation, independently growing last beech fagus forest, spruce bast tree infested

attacked bark bast beech beetle bushgrass calamity caused chop cut cycle dead down ecological environment europe european forest forests growing helicopters hole independently infestation infested insects ips larva larvae logging making military opening part pest phloem planting pupa salvage scolytinae sky smallreed spruce stands stump tree trees typographus way wood