Fraser fir this purpose. Fraser fir has been used more times as the White House Christmas tree (the official Christmas tree of the President of the United States's White House) than any other tree. It is grown in plantations in Scotland and sold by the thousands throughout the United Kingdom and Ireland. It is also cultivated from seedlings in several northern states in the USA and adjacent parts of Quebec province, especially for the Christmas tree trade. The combination of form, needle retention, dark blue-green color, pleasant scent and excellent shipping characteristics has led to Fraser fir being a most popular Christmas
WAVL tree WAVL tree In computer science, a WAVL tree or weak AVL tree is a self-balancing binary search tree. WAVL trees are named after AVL trees, another type of balanced search tree, and are closely related both to AVL trees and red–black trees, which all fall into a common framework of rank balanced trees. Like other balanced binary search trees, WAVL trees can handle insertion, deletion, and search operations in time per operation. WAVL trees are designed to combine some of the best properties of both AVL trees and red–black trees. One advantage of AVL trees over red–black trees is that