Recently moved into a new neighborhood in the Berkeley Hills. There
isn't another California coast live oak for at least half a block, so
they must be transported by more than just gravity or wind. A neighbor
walking by saw me pulling a few and commented that sometimes birds
drop them. I think maybe squirrels might be redistributing them. I
found one under my deck (growing between a concrete tile crack), which
doesn't have any reasonable path for an acorn to travel unless it was
moved there. I'm pretty sure they're sprouting from the acorns, as
the few I've pulled usually have the shell of the acorn attached to
the root.

Not sure what to do other than pull them. I tried using 1% Roundup
from a spray bottle, but they seem resistant. I wasn't sure if maybe
the leaves had to be cut to improve absorption. Once I visited a
local botanical garden, and chatted with some of the gardening crew.
They commented that live oak acorns distribute everywhere, and lots of
their time is spent pulling saplings from the garden. I sometimes
hike on trails where the acorns are just everywhere.

We've been having a certain problem in Berkeley with a few planted
live oaks that are planned for removal on University of California
property.