Fraser fir tree species. Growing and harvesting this species for Christmas trees and boughs is a multimillion-dollar business in the southern Appalachians. North Carolina produces the majority of Fraser fir Christmas trees. It requires from 7 to 10 years in the field to produce a high tree. In 2005, the North Carolina General Assembly passed legislation making the Fraser fir the official Christmas tree of North Carolina. Fraser fir The Fraser fir ("Abies fraseri") is a species of fir native to the Appalachian Mountains of the Southeastern United States. "Abies fraseri" is closely related to balsam fir ("Abies balsamea"), of which it
Noble polyhedron 'dual' covers both kinds. The dual of a noble polyhedron is also noble. Many are also self-dual: Noble polyhedron A noble polyhedron is one which is isohedral (all faces the same) and isogonal (all vertices the same). They were first studied in any depth by Hess and Bruckner in late 19th century, and later by Grünbaum. There are four main classes of noble polyhedra: If we allow some of Grünbaum's stranger constructions as polyhedra, then we have two more infinite series of toroids: We can distinguish between dual structural forms (topologies) on the one hand, and dual geometrical arrangements when