How should I document property line trees my neighbor is threatening to cut?

Hi tree law! I have a mature 30+ year old laurel hedge that sits on (or very near) the property line. It's 10+ feet tall and provides amazing greenery and privacy. My neighbor on that side needs to put an impermeable fence on her side of the property line to maintain her daycare license.

Currently we're working together to solve the problem, but she's told me a few times that folks she's had out to give quotes say "the hedge needs to be removed."

This neighbor is a little bit of a wild card and the way she's talking about the project is starting to make me nervous. What should I be doing now to document the hedge age/health etc. in the event that she goes rogue and cuts it down and/or hires someone who damages the roots?