All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
We have already issued Fataawa 89840, 83628 and 86876 clarifying with evidence and the statements of the scholars that it is not permissible to celebrate Christmas. Furthermore, it is not permissible for a Muslim to participate in this celebration with any kind of participation, among which is what you mentioned: putting the Christmas tree at a corner of the house, because this is imitating non-Muslims in their religious rites and the Prophet said: “Whoever imitates a people he is one of them.” [Abu Daawood]
As regards the Christmas tree, it has nothing to do with the tree behind which the Jews will hide when the Muslims will fight them at the end of the times. The tree of the Jews is called Al-Gharqad. Abu Hurayrah narrated that the Prophet said: "The Hour will not come until the Muslims fight against the Jews and the Muslims would kill them until the Jew would hide behind a rock and a tree, then the rock or the tree would say: “O Muslim, O slave of Allaah, this is a Jew behind me, come and kill him, except the Gharqad, which is a tree of the Jews.” [Muslim]
However, the Christmas tree is a symbol of the Holly tree that the Christians claim that it miraculously grew out of season in order to hide the Holy Family when they were fleeing King Herod’s soldiers on their way to Egypt.
Allaah Knows best.