That's an interesting question. The area originally was Coastal Sage Scrub which is native to California. There is still much of this present on the steep slopes towards the ocean, but it is now mixed with introduced species such as willow. The more level areas are now covered in a mix of trees including Monterey Cypress and Eucalyptus. While Monterey Cypress is native to the Monterey Peninsula about 60 miles south, it was not originally found in San Francisco. Eucalyptus was imported from Australia in the late 1800's as a replacement for the Coast Redwood trees that were all logged off by the mid-1800's. Unfortunately, the wrong species of Eucalyptus tree was imported and it is valueless for lumber (or anything else).There were many other species of trees that I did not examine carefully, but my guess is that most are non-native ornamentals.
At the time that Ferries and Cliff House Railway was built, the city of San Francisco ended about three miles inland from the coast and sand dunes occupied much of this area. This was partly the reason that F&CH RY ran up to the coastline instead of directly to the beach. To create Golden Gate Park and the new housing areas, much reclamation had to occur with a tremendous amount of fill dirt dumped to stabilize the area. Nearly all of the vegetation from the edge of Golden Gate Park to the coast is introduced.
I'll post more pics later today...