I don't know of any religions that are against trees. And the Christmas tree's ties to Christianity are tenuous at best, pagans have been using evergreen boughs for centuries to decorate temples and whatnot, and the practice in Germany (where modern Christmas trees come from) likely came from that.
My Jewish coworkers also like Christmas trees, they just don't put any Christian symbology on it. If ties to Christianity were clear, we wouldn't allow our governments to place them in public areas.
Most of the decorations are non-religious. Baubles descend from representations of apples for the "were halfway through winter" party, lights are just pretty, all that's religious is the star, but also stars are pretty. Mine has a flying spaghetti monster that my daughter made for me out of pipe cleaners in the mid 2000s
Christmas has little to do with Christianity by the time you start decorating trees n shit. I'm an atheist, born and raised. We still had a tree and everything. If anything, our pagan forefathers celebrated summer solstice long before they met any Christians and probably long before Christ even walked the earth.
Also in my previous comment I did mean winter solstice - but we do also celebrate summer solstice and always have. In the winter, there's a feast, which was supposed to be necessary to have a bountiful new year. In the summer, big fires are made to celebrate the sun. There were different gods and other mythological figures, but the key part that's still survived to this day, is sun worship. And to me, that's the most sensible religion you can have. One of the best comedians of all time agrees with me - or maybe I took it from him