You're confusing Yule logs with solstice evergreens, neither of which was really very similar to Christmas trees (the Yule log was literally a log that was burned, and solstice evergreens were stripped of their branches, stood outside, and more closely resembled may poles). That article is really not a good source:
When Roman Emperor Constantine decriminalized Christianity in 313, the religion began to spread throughout Europe. These early Christians adopted and incorporated many pagan rituals (fertility rites of the spring were converted into Easter bunnies and eggs) and the Christmas tree evolved from those winter solstice celebrations.
Leaving aside the fact that Christianity was already decriminalised by Constantine's predecessor Galerius, this paragraph is just plain wrong. The "early Christians" did not adopt the pagan rituals described. That happened much, much later; indeed "Easter bunnies" are a twentieth-century American invention, not ancient or medieval at all. This article is exactly the kind of popular misconception that plagues discussion of this topic.
The truth is that Christmas trees are not attested until the sixteenth century at the very earliest, and even then the evidence is pretty sketchy; they didn't become widely used until the eighteenth or even nineteenth centuries. So any claim that the custom is based on pre-Christian rituals needs not only to show that those rituals were in fact similar to the Christian ones (rather than simply assuming that any ritual involving a tree was basically the same thing) but also to explain how those rituals jumped from pre-Christian times into early modern times without apparently existing in the intervening period. In fact, sacred trees are so common in religion and folklore throughout the world that trying to identify a single pre-Christian source for Christmas trees is both impossible and pointless; it's just something that people tend to do no matter what their culture, so it doesn't really need a particular historical source.
As with most of the "Christian festivals are just rebranded pagan festivals" claims, this one rests on the assumption that the way these festivals are celebrated today reflects how they were always celebrated, allowing one to see a line of continuity from paganism into Christianity. But in fact most of the customs we are familiar with surrounding Christmas and also Easter are recent innovations. Christmas as we know it was a nineteenth-century invention. It was celebrated quite differently in early modern times and
completely differently in the Middle Ages. This makes it very hard to see any historical continuity between pre-Christian practices and modern ones, because there's a gap of many centuries in between them.
Besides which, all of this is a sideshow. As I said before, the question of whether and when pagan customs were later incorporated into the way in which Christmas is celebrated is irrelevant to the question of the
origins of Christmas, and it has absolutely nothing whatsoever to do with the historical existence or otherwise of Jesus.