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,
White House Christmas tree in 1997 there were 36, in 2008 there were 27. Traditionally, the tree in the Blue Room is the official White House Christmas tree. The White House Christmas tree usually stands nearly 20 feet tall and the crystal chandelier in the Blue Room must be removed for the tree to fit the room. Frequently, the tree's height is reported as 18 or 18½ feet tall. The Blue Room 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 trade group.