Oak trees reach their peak acorn production between 50 and 80 years of age.

Oak trees produce the most acorns once they reach 50 years old. Acorns are
the reproductive nuts of oak trees, and the rate of acorn growth continues
until the oak trees are approximately 80 years old before it gradually
declines. It takes an average of about 20 years before an oak tree even
begins to produce acorns. Mass acorn production generally occurs every 2 to
5 years. Since acorns are heavier than other plant seeds, oak trees cannot
rely on the wind to spread them out to grow new trees. Instead, acorn
dispersal is largely due to squirrels and jay birds collecting acorns and
spreading them out to grow.