Wait wait I might actually have an answer

Tolkien wrote The Hobbit like waaaay before he even dreamed up the idea for Lord of the Rings, so when he DID dream up LotR, he had a whole bunch of stuff that didn’t make sense. Like plotholes galore

Like for example in the first version Gollum was a pretty nice dude who lost the riddle contest graciously and gave Bilbo the ring as a legit present and was very helpful and it was super nice and polite and absolutely nobody tried to eat anyone because this is a story for kids and that’s very rude

But that doesn’t work with LotR, so Tolkien went back and re-released an updated version of The Hobbit with all the lore changes and stuff to fix everything that didn’t work

This is the version we know and love today

BUT rather than pretend the early version never existed, Tolkien went and worked the retcon into the lore

If you pay attention in Fellowship, there’s a bit where Gandalf is telling Frodo about the ring and he mentions how Bilbo wasn’t entirely honest about the manner in which it was found

To us modern readers, this doesn’t make a ton of sense, so mostly we just breeze by it–but actually that line is referencing the first version of The Hobbit

The pre-retcon version of the Hobbit is canonically Bilbo’s original book. The original version with Nice Gollum is canonically a lie Bilbo told to legitimize his claim to the ring and absolve him of the guilt he feels for his rather shady behavior

Then the post-retcon version is an in-universe edited edition someone went and released later to straighten out Bilbo’s lies

So it’s 100% plausible that the in-universe editor who fixed up Bilbo’s Red Book and translated it from whatever language Hobbits speak was a human who knew about Christmas Trees and tossed the detail in to make human readers feel more at home, because that’s the kind of thing that sometimes happens when you have a translator editor person dressing up a story for an audience that doesn’t know the exact cultural context in which the original story was written

Tolkien was a medieval scholar and medieval stories are rife with that sort of thing, so like… yeah

There’s a good chance it maybe did cross his mind

@old-gods-and-chill LOOK AT THIS THAT’S SO COOL

Not only all that, but Tolkien was also working within a frame narrative that he wasn’t the real author, but a translator of older manuscripts; so, in-universe, the published The Hobbit isn’t actually Bilbo’s book, but rather Tolkien’s copy of an older copy of an older copy of an older copy of Bilbo’s book. So when errors and anachronisms came up, he would leave them there instead of fixing them, and he may have even put some in intentionally; what we’re supposed to get from the “Christmas tree” bit is that the first scribe to translate the book from Westroni to English couldn’t come up with an accurate analogue for whatever hobbits do at midwinter.

Yes. Another example of tolkien doing this is him using, for instance, Old High Gothic to represent Rohirric - not because the people of Rohan actually spoke that language, but because Old High Gothic had the same relationship with English that Rohirric had with Westron (Which is the Common Language spoken in the West of Middle-Earth). There’s tons of that stuff in the book.

Like, Merry and Pippin’s real names (In Westron) are Kalimac Brandagamba and Razanur Tûk, respectively (to pick just one example of this). Tolkien changed their names in English to names which would give us English-speakers the same kind of feeling as those names would to a Westron-speaker. Lord of the Rings is so much deeper than most readers realise.

tolkein’s entire oevre is just one epic in-joke with the oxford linguistics department imo

eragon

eragon

Peasants.