Actually, those are all Blue Gum. Typical coastal eucalyptus. Considered by many environmentalists to be invasive weeds (with some justification, and the only understory, usually, is poison oak - personal experience, from a surveying job early in my career). Preferred action is to exterminate & replace with something native like manzanita or baccharis bushes or maybe redwoods (latter don't do well on the coast itself - too sensitive to salt spray).