Language Alert: "Heritage Tree"
Term: "Heritage Tree" (aka "Heritage oak", "Heritage spruce", etcetera.)
Definition: A tree that is large, old and probably decrepit.
Implication: It's the city's job to identify all the big, old trees in the city and make sure nobody ever cuts them down or does anything on their property that might endanger them. This is called "protection of the urban forest" and is accomplished by way of an urban forestry board, empowered to enforce a heritage tree ordinance.
Preferred terminology: "Big, old tree."