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 cultivation urine samples. The average Christmas tree receives roughly a half of an ounce (14 g) of pesticide over its lifetime. The BBC's "Gardening" website called buying Christmas trees directly from the farm, "the most environmentally friendly way of getting a tree". Other positive environmental attributes have been given live Christmas trees as well. Researchers at the University of Nebraska included the reuse of natural Christmas trees as mulch and, in larger quantities, piled up as soil erosion barriers, among the benefits of live tree use. Other positive reuses included fish habitat in private ponds and backyard bird feeders. Since 2004,