So, it's more interesting than this. The trees are playing the squirrels. There's a normal amount of acorns that can support a normal amount of squirrels. But once every few years, the trees make a bunch more acorns. More than the normal amount of squirrels can eat. But not frequent enough that the number of squirrels increase. So the squirrels go crazy and hide em everywhere that year, but there's no way they can eat them all, so there are a bunch of acorns planted.
Tldr: trees manipulate # of acorns to get squirrels to plant more.