A deciduous Bonsai like a maple tree would need to be kept during winter in conditions you would find in a cold frame greenhouse - cold enough to let them go into dormancy, but not so cold as to freeze their roots.
Possibly, if you keep it away from road salt, and spray. A big reason for some losing plants, shrubs, trees, etc. this year, due to such brutal winter conditions with it. Many different type shrubs can be trimmed in bonsai fashion.
Can they live threw winter
