Douglas fir menziesii". The coast Douglas-fir variety is the dominant tree west of the Cascade Mountains in the Pacific Northwest, occurring in nearly all forest types, competes well on most parent materials, aspects, and slopes. Adapted to a moist, mild climate, it grows larger and faster than Rocky Mountain Douglas-fir. Associated trees include western hemlock, Sitka spruce, sugar pine, western white pine, ponderosa pine, grand fir, coast redwood, western redcedar, California incense-cedar, Lawson's cypress, tanoak, bigleaf maple and several others. Pure stands are also common, particularly north of the Umpqua River in Oregon. Poriol is a flavanone, a type of flavonoid, produced
Tree walking automaton Tree walking automaton A tree walking automaton (TWA) is a type of finite automaton that deals with tree structures rather than strings. The concept was originally proposed by Aho and Ullman. The following article deals with tree walking automata. For a different notion of tree automaton, closely related to regular tree languages, see branching automaton. All trees are assumed to be binary, with labels from a fixed alphabet Σ. Informally, a tree walking automaton "A" (TWA) is a finite state device which walks over the tree in a sequential manner. At each moment "A" visits a node "v" in state