I am in zone 8b and used the foam tubing before on my fig trees. I even covered the branches. By the end of winter all branches were dead. The main trunk was over 2" thick and the top part still got hit. I’m not sure that this type of insulation is enough or good in your zone. Wrapping tour tree with dried leaves allows the tree to breath while protecting it from wind which is more destructive than the cold is probably better than foam which might suffocate it and cause rot.