Thanks two good reads you have bestowed upon me so far

Devils' advocate (Don't mean you personally, Bob): One thing it does of course do, is protect plants against the peak dips in the coldest hours of the night: Any heat in the pot takes longer to dissapate and as such, pot temps are much less extremen. Which might just make a difference. A little like a unheated greenhouse does not cool down as much as the surroundings (I still have growing/living pepperplants in mine, even after a few nights of frost!)

leatherback wrote: Devils' advocate (Don't mean you personally, Bob): One thing it does of course do, is protect plants against the peak dips in the coldest hours of the night: Any heat in the pot takes longer to dissapate and as such, pot temps are much less extremen. Which might just make a difference. A little like a unheated greenhouse does not cool down as much as the surroundings (I still have growing/living pepperplants in mine, even after a few nights of frost!)

That's why I asked Bob how he proposes to apply bubble wrap. For a pot, the outside packed in bubble wrap, it will hardly make a difference - it may take a little bit longer, but eventually the tree and its roots will get just as cold as its surroundings. There's quite a difference with an unheated greenhouse, that is closed and is placed on the floor.
Packing the complete tree in a frame covered with plastic and placing that on the soil would work (protecting it from the sun though, as it could get quite warm in there by day - so the temperature difference will even be more extreme - this is also written in the article I linked)

Hi, I am also in a similar situation where I cannot decide where the best place to keep my juniper bonsais is. Currently it is ~35-50 deg F and I have been keeping them outside. I was wondering because I just repotted one of them so I’m not sure if it will be more susceptible to the cold and wind. I am also not sure if the size of the juniper should affect the placement location of the plant. (Small plant=indoors, larger plant=outdoors?)

Andrew89162 wrote: (Small plant=indoors, larger plant=outdoors?)

Nope. Junipers, big or small, must be outdoors.
1,6 C is'nt cold. Your plant can easily handle that.