The trees of Southern California are a diverse group that occupy several different ecological regions including a humid temperate domain (South Coast and Transverse Ranges) and a dry domain (Mojave and Colorado Deserts). Each area has its characteristic vegetation, but there is also a good deal of overlap among regions. At times it is difficult to say whether a species is a tree or a shrub, and this page is intended to be limited to those taxa which are usually large woody plants with a single main trunk, but will also include species generally recognized as trees although they may have multiple stems or trunks. I somewhat arbitrarily consider plants that reach 25' or 30' to have graduated beyond shrubs, and plants in this height range are often described as shrubs or small trees. I have also decided to divide this site into three categories: coniferous trees (pines, junipers, etc.), deciduous broadleaf trees (oaks, maples, etc.) and evergreen broadleaf trees (oaks, toyon, buckeye, etc.). The idea for this page began as a place to display photographs of the barks of the various trees, something that I have not included in my other site. It is an ongoing project and some of the species that are included do not have the appropriate photos yet, but that will hopefully be rectified soon.

Coniferous trees
Deciduous broadleaf trees
Evergreen broadleaf trees

References:

Collins, Barbara Key to the Trees and Shrubs of the Deserts of Southern California
Collins, Barbara Key to the Trees and Wildflowers of the Mountains of Southern California
Lenz, Lee and Dourley, John California Native Trees and Shrubs
Peterson, P. Victor Native Trees of Southern California
Roberts, Fred M. The Oaks of the Southern California Floristic Province
Stuart, John D. and Sawyer, John O. Trees and Shrubs of California