It would be interesting to know if the cycles originate with the trees themselves, or if they are determined by outside influences such as rain, heat, etc.

I have read that apples tend to produce well every other year. I have some blueberries that do the same, but it may be caused by neglect, rather than OTHER outside influences!

Sue

Oaks in California are a masting species, this means that they produce large amounts of seeds in some years, and few to zero seed in other years. Many species mast, and the reasons for masting are not well understood. Some scientists believe that fruiting is caused by an environmental trigger related to temperature or water.

One study showed that masting in another species of plant was related to seed predation by insects. In years of low production of seeds, seed predator populations decrease, and in high production years, the seeds get a chance to germinate because there are more seeds than pests.

Generally with valley oaks, the amount of seed production will be pretty much the same throughout the entire species range, with a few exceptional trees producing acorns.
But luckily for animals, often other species of oak such as coast live oak will produce its acorn crop in valley oaks bad years.

Many species do this sort of thing- there are a number of ocean species that all breed at the same time in a spectacular display. All at once- boom. If they did it a few at a time- then predators would surely eat the majority before they produce offspring. As stated above- if there's tons of acorns- then animals will likely quit when full or miss many more than if they were foraging for a few at a time.