Regulations about collecting driftwood and other natural materials on Orange County beaches vary. Some places, such as tide pool areas and nature reserves, don't allow any natural materials to be collected. Any restrictions are usually posted at the beach.
In Orange County there are a number of marine life refuges and reserves
, with varying rules. You cannot collect driftwood at Little Corona, Doheny State Beach, or the Heisler Park tidepool areas. From what I can tell, new rules for the reserves will soon take effect, and I'm not at all clear what those rules will be. Crystal Cove State Park
used to allow you to collect 50 pounds of driftwood a day, but they seem to have changed that. Now collection of any natural materials is prohibited.
The good news is that there should be no problem collecting driftwood at beaches that aren't part of any protected area. Most California beaches have no restrictions.
Driftwood is most abundant in Northern California, but Central California still gets a good amount. It's sparsest in Southern California.
Good luck with your beachcombing.