The Forest...

...for which the city is also named consists mostly of Eucalyptus trees . It is man made, and was created in the first decade of the 1900's when a local landowner, Dwight Whiting, planted 400 acres of Eucalyptus groves. In the late 1960's the Occidental Petroleum company developed a residential community in and around the groves, which had long since expanded and grown much  more dense.
I just walked outside to take the photo, we live at the edge of the forest. In the photo there is a native tree: a  h u g e California Pepper Tree. 
The Eucalypti grow up to 300 feet and shed the dead outermost layer of bark in flakes or ribbons. In Australia the timber is commonly used in buildings and fencing, the investors, who planted our trees wanted to use those for railroad track ties but the wood is not suitable for it, because only the old 70-100 year old trees are used for commercial use.
This tree is non native and is devastating to the native plants and the entire ecosystem's balance can be thrown off.
And in the extra: Tiny Tuesday - an eucalyptus leave