The Mediterranean area of California occupies a narrow coastal strip from Cape Blanco, in the United States, to Punta Baja, in Mexico, its centre roughly corresponding to San Francisco. In an easterly direction, this strip stretches for some 100 or 200 kilometers towards the interior of the continent. Despite its small size (approximately 10% of the total biome), this is the area that presents the greatest continuous stretches of unaltered Mediterranean landscape. It contains some 4,300 known species of which 35% are endemic. In climate terms, there is marked seasonality: 85% of rainfall is concentrated in winter. The summer drought is very severe, although coastal mists partly temper this contrast.
Californian forests present many ecological and evolutionary similarities with those of the Mediterranean basin. Many genera are common to both, such as Pinus, Quercus, Arctostaphylos, Arbutus, Salvia, Artemisia, etc. Wildfires have a similar natural recurrence, the fertility and diversity of soils is comparable, and many species show similar adaptations.