raised garden beds and overwintering

someone I know, from whom I got a fairly decent maple bonsai, recommended burying trees into a raised garden bed, for the winter. This would seem to make sense, the raised beds won't freeze as redily, and the fact that the trees are lower than the top of the raised bed, it would protect them from wind. The one's I have are being used for tomato plants, now and the only issue I could think about would be a lot of sun. Do any of you have experience with such things? or any ideas?

this is the Kind of thing I'm Walking about.

Anything you read in an online site should be adjusted to local climate. Right now in some parts of North America the leaves are falling. Around here, not until November.

It rarely gets cold enough here to make burying the pots worth doing. In other places you need to.

Find a local club and find out what they do. They know the weather. Listen to the member who has had the most trees longest.

They guy who mentioned doing that is from not far from where I am. this last winter we only had a few weeks where the temperature was -5 or lower. and not constantly. It does vary though.

If you get sustained -20c winters that.might be needed. I get dips into that area maybe for a night or few days, and it is overkill here, certainly for such hardy species.

thanks.