An interesting article on the
history of eucalyptus in California and the fight over their removal.
It has an amusing parallel in that much like the federal law that protected wild horses to the point that they became a detriment on the ecology, Santa Cruz has a law, the Heritage Tree Ordinance, that protects eucalyptus trees as an important symbol, even to the detriment of public safety (they are highly flammable and fall over a lot) and local ecology.
Most land and park management agencies advocate for the complete removal or extensive restriction of eucalyptus trees. I know the East Bay Resional Park System (Alameda and Contra Costa counties) has extensive projects in many of its parks to replace eucalyptus with native species. Eucalyptus is a main reason why there is no redwood second growth in the Oakland hills (which used to have redwood forests just as impressive as on the Mendocino coast).