The whole topic is subjective to me ... when was the last time anyone went to a tree auction and brought home a 50 tonne bargain.
The true value of something is usually decided by the laws of supply and demand ... trees seem exempt from that law unless in a nursery etc.
Some-one might say the tree adds $10k value to their home.
And the builder will say, yeah, piss it off and put a double auto rolladoor carport with covered entrance and lights to the house will add $25k