In some places the oak seedlings are so thick that it looks like six inch high ground cover. The quercus agrifolia last winter dropped a pretty big crop of acorns. Not as many as they dropped in winter 03-04 that preceded the 04-05 El Nino but still quite a lot.
Since I believe the Quercus agrifolia anticipate the climate and don’t just react to it, the indication of them setting out seedlings in advance of the El Nino shows that they (know?) anticipate a large rain event is coming. They drop a lot of acorns in a relatively dry year to get seedlings established. Over the summer those seedlings will be thinned out and by the time the rains come in the late fall those that survive will be positioned to take advantage of an abundant rain season.
Of course the oaks exist on a different time scale than humans. To them season to season is like another day to us. The last time the El Nino came it seemed like they looked out and (“said”) “it looks like it’s going to rain tomorrow, we better get these plants started.” And they shook off a bunch of acorns to get the process going. It just so happens that that was in the winter that preceeded the El Nino. These oaks don’t so much react as adapt to and anticipate coming weather events. That’s why the statistics of acorn production may look like they don’t have any relationship to climate events. Thats because if we would look for the oaks to be a trailing indicator the statistics wouldn’t make sense.