Hi Susieqz,
What are your low temps ?
I tried this last winter something that make sense to me :
I keep my trees small . This means under 2 meters - that is the only way you can protect them IMO.
I tie them branches to the center of the tree.
I then push a dark 80 liters trashcan over them - that trashcan is with removed bottom.
I then fill the trashcan with compost from a nursery - that compost will be used at spring time around the tree to give the tree some nutrients .
I put two stakes around the tree/trashcan - and I put the bag from the dark bag with inside out from the compost over the stakes.
This prevents water to go inside the compost.
VoilĂ Madame !
I'll make a post with photos with this technique - although the last winter was mild so still not rocket proofed - but I think this one should give good results ! So I'll stick to it for the next years.
The two main ideas are that the dirt keeps the roots when the trunks go die-back in no protection mode and also that the dark color attracts/holds sun-heat .