bark beetle pest ips typographus, spruce and bast tree sap fluid infested and attacked by european spruce, making their way wood

attacked bark bast beech beetle burrow calamity caterpillar caused chop cut cycle czech dead detail down ecological environment europe european fluid forests hole infested insects interactions ips larva larvae logging making opening part pest phloem pine planting pupa salvage sap scolytinae small spruce stands stump tree trees typographus way wood