Hello everyone,
I am working out a plan to effectively over-winter my trees this year. I live in North Dakota where temps get to -30F (-35C) not including wind. I have a couple options available to me but I have one fundamental question.

Do conifers need sunlight when they are dormant?

I have read that basements or refrigerators can be used which implies conifers don't need sunlight. However, I recently listen to a podcast from a bonsai professional recently that said they do need it even when dormant.

Thoughts? Suggestions? Thanks!
Spencer