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,
National Christmas Tree Association National Christmas Tree Association The National Christmas Tree Association (NCTA) is a professional organization in the United States of over 5,100 "Christmas tree professionals" in various capacities. The group focuses its work into three areas: promotion and research, federal representation (which includes Congressional lobbying), and professional education. The association was founded in 1955 and has more than 1,800 members. The official White House Christmas tree, or the Blue Room Christmas Tree, is donated each year by the National Christmas Tree Association (NCTA). The NCTA has donated the tree since 1966; it is chosen through a contest among members of the