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
Tree automaton three statements are equivalent: Tree automaton A tree automaton is a type of state machine. Tree automata deal with tree structures, rather than the strings of more conventional state machines. The following article deals with branching tree automata, which correspond to regular languages of trees. As with classical automata, finite tree automata (FTA) can be either a deterministic automaton or not. According to how the automaton processes the input tree, finite tree automata can be of two types: (a) bottom up, (b) top down. This is an important issue, as although non-deterministic (ND) top-down and ND bottom-up tree automata are