There should be some sort of system to “nominate” a species (such as the conifers mentioned in the original post) as being automatically assumed cultivated for a given state. It is unreasonable to expect people to clean up the 1,000s of observations in this manner.
Whatever system there currently is clearly insufficient and unsustainable for these purposes. Even if it’s native to the state, that’s fine: Anything over the 50% cultivated threshold should be considered fair game to automatically set to “cultivated” unless marked otherwise.