Pinaceae, Taxodiaceae, Cupressaceae and Araucariaceae are collectively referred to as Pinaceae, Taxodiaceae, Cupressaceae and Araucariaceae. Among them, most of the cypress trees do not show triangular tower shape, and are rarely used as Christmas trees; At the same time, Araceae trees are native to the southern hemisphere (except New Zealand, Australia and other places in the southern hemisphere). They are usually only used as Christmas trees in the southern hemisphere, and rarely used as Christmas trees in other regions; In Pinaceae and Taxodiaceae, because the number of species in Pinaceae is more than ten times that of Taxodiaceae, Pinaceae plants are often used as Christmas trees.