Among others he found the North American species Picea sitchensis to be suitable for Norway, during a study trip in 1916 and 1917.
Species from the Alaskan coastline and islands have also adapted well in the Faroe Islands, especially Pinus contorta, Picea sitchensis, Salix alaxensis, Populus trichocarpa and Alnus sinuata.
Picea abies | Picea engelmannii | Picea mariana | Picea glauca | Valeriana sitchensis | Picea sitchensis | Picea glehnii |