How split is too split to save a tree?

How split is too split to save a tree?

I've got a couple of companies coming next week to tell me what they can or can't do, but I wondered if anyone here had an expertish opinion? Live oaks are not made for frolicking in the snow.
Audrey III? Help on plant identification:

Audrey III? Help on plant identification:

Color request

Color request

Update on Wild Thing

Update on Wild Thing

Apartment of geekness

Apartment of geekness

changing it up!

changing it up!

Garden wildlife

Garden wildlife