Christmas tree cultivation major Christmas tree growing region, Douglas-fir has always been the primary species grown. A full one-half of all trees produced in the Pacific Northwest are Douglas-fir. Douglas-firs typically take five to seven years before they are mature enough to sell as Christmas trees. Also common in the region are noble fir, a tree which commands a higher price than Douglas-fir, and grand fir, which accounts for about 10 percent of the annual harvest in the Northwest. Other species collectively account for only 3–5 percent of the total Northwest harvest. In North America, Fraser fir, grown in the Appalachian Mountains of
Search tree their node length, B-trees are optimized for systems that read large blocks of data. They are also commonly used in databases. The time complexity for searching a B-tree is O(log n). An (a,b)-tree is a search tree where all of its leaves are the same depth. Each node has at least a children and at most b children, while the root has at least 2 children and at most b children. a and b can be decided with the following formula: formula_1 The time complexity for searching an (a,b)-tree is O(log n). A ternary search tree is a type of