It seems like almost every freeride trail in California is either illegal (hidden) or in a paid bike park, such as Mammoth. Thank goodness, there actually is a jewell hidden in the redwoods. A trail network packed with epic singletrack, jibs, a plethora of log rides, jumps, and relatively steep terrain. Its called Soquel Demonstration Forest, which borders the Forest of Nisene Marks in the Santa Cruz area. If you are anywhere near this area of central California, you'll want to spend some time on these trails.
Here's a youtube video depicting a portion of the trails and some of the log rides, etc. Its a bit cheesy and poor quality, but gives an idea of the area:
Find plenty of trail maps and descriptions of the rides in the "Demo Forest" here!
The first pic (up above) is girl hucking a tree stump on the Braille Trail...she's riding a Santa Cruz Bullit. And a glimpse of someone riding a skinny: