The idea itself is interesting, but that sprite is mostly just a recolor - especially on the snow... right? which, does not get corrupted anyway. To begin with, snow is unaffected by corruption (and crimson and hallow) and boreal trees grow on snow, so at things are right now... they can't be currupted anyway.
However, yeah, the idea is interesting. But, then what would they drop? Ebonwood? Boreal wood? Something else? The sprite might could reflect that. if it just drops boreal wood, then why to change it. if it drops ebonwood, then why not recolor it to a gray-ish color and stuff? similarly how ebonwood is (look at corrupted palm trees too, how they look like palm trees but have the color theming of ebonwood and corruption, I think... (and, likewise, they drop ebonwood).
Plus, boreal trees have several variants. If you ask me, the pine-like trees look better, like, I think it makes more sense to see a pine forest there, than a bunch of trees without any leaves XD But maybe that's just me XD
