spruce bark beetle pest ips typographus, spruce forests infested drought, attacked by the european clear cut calamity

acid attacked bark beech beetle calamity caused chop civilization cut cycle czech dead down drought dry ecological environment europe european forests global human infested insects interactions ips larvae logging nitrogen original oxides ozone pest phloem pine planting pupa rains salvage scolytinae small spruce stands stump sulfur tree trees typographus warming