Yes, I wrap my trees with garland. I doubt the grapevine and evergreen garland keeps my trees warm, but the act of wrapping the tree trunks comforts me, and keeps me warm. No matter what a garland wraps, the big idea is about warmth. Gardeners in northern climates have a few months of bitterly cold weather ahead of them. Any expression of warmth is welcome now. Yes, please.
I will confess that I go to great lengths to ward off the winter. I am guilty as charged. Beyond those charges, the construction and the installation of garlands for the holiday and winter keeps me happy, and busy.