the brockenbahn narrow-gauge railway in the german harz mountains travels through the forest destroyed by bark beetles up to the

tree green nature damage forest dead destruction spruce bark wood germany beetle environment protected conservation death vegetation outdoor atmosphere german plague decline harz wilderness trees brocken catastrophic mountains dieback brockenbahn flora mountain pine climate change conifer dying ozone dryness reserve biodiversity landscape monoculture narrow gauge railway locomotive train old narrow-gauge travels destroyed beetles