This isn’t completely fair, Bethesda addressed the issue in universe and there are multiple authors arguing about this and why that is. It plays very well with the rest of the lore which is all about conflicting accounts and variety of interpretation.
If I recall correctly the three in-universe theories are (1) it’s an error and there never was a jungle (2) there was a jungle but Talos CHIMed it away (3) there was a jungle when the high elves (Ayleids) lived there, but when the humans took over the white-gold tower changed the landscape to suit them.
Unfortunately, /r/teslore has no fediverse equivalent that I know of so I wouldn’t know where to have this kind of discussion.