Picea abies outside of its native range, and one of the most economically important coniferous species in Europe. It is used as an ornamental tree in parks and gardens. It is also widely planted for use as a Christmas tree. Every Christmas, the Norwegian capital city, Oslo, provides the cities of London (the Trafalgar Square Christmas tree), Edinburgh and Washington D.C. with a Norway spruce, which is placed at the most central square of each city. This is mainly a sign of gratitude for the aid these countries gave during the Second World War. In North America, Norway spruce is widely planted,
Christmas tree tree in most parts of the country, owing also to its faded winter coloration and limp branches, making decorating difficult with all but the lightest ornaments. Norfolk Island pine is sometimes used, particularly in Oceania, and in Australia, some species of the genera "Casuarina" and "Allocasuarina" are also occasionally used as Christmas trees. But, by far, the most common tree is the Monterey pine. "Adenanthos sericeus" or Albany woolly bush is commonly sold in southern Australia as a potted living Christmas tree. Hemlock species are generally considered unsuitable as Christmas trees due to their poor needle retention and inability to