Yes, however these trees are grown and potted for the purposes of looking fresh and lush for the whole Christmas period not for the purpose of replanting. There is about a 50% chance that if replanted into the ground that they take root.
If you are buying a tree with roots specifically for the purposes of replanting we recommend never taking the tree inside and making sure it stays watered. The best time to replant the trees is between February and April and if they do take root they will grow about a foot a year until they have maximised on the conditions the environment allows. 