How Tall Do Oak Trees Have to Be Before They Bear Acorns?

Age

• The age of an oak tree, rather than how tall it is, determines when the oak begins to produce acorns. The majority of oak species start bearing acorns at about 20 years of age, with peak production occurring as the tree matures to between 50 and 80 years old. Upon reaching 80 years of age, acorn production starts to languish. How tall the tree must be to grow acorns also depends on the species, as more than 100 species of oak exist, each with varying height potential.

White Oak

• One of the most common oaks, the white oak (Quercus alba) achieves a mature height of between 50 and 80 feet. It possesses a slow to medium rate of growth, which, according to the Arbor Day Foundation, denotes a tree that grows less than 24 inches annually. Assuming that it grows to its full potential of 2 feet each year, and requires 20 years before it begins bearing acorns, the white oak tree will be nearly 40 feet tall before it begins to provide the nut. A similar equation can be used for other oak species.

Production Levels

• Some oaks produce more acorns than others, especially if they are taller and have a larger canopy than surrounding trees. This exhibits the oak's exceptional health. Often when an oak produces a large number of acorns one year, the following season will see diminished production of the nut due to a reduction in the amount of available nitrogen in the earth. Once the nitrogen is replenished after approximately one year, full production again commences.

Environment

• The number of acorns may also be limited due to environmental factors such as freezing temperatures that occur during the flowering period. This kills the flowers from which the acorn emanates and thus minimizes the acorn crop. High winds and large amounts of rain, in addition to insect infestation, and a lack of soil moisture also tend to limit acorn development. When the oak is stressed by these environmental concerns, it may prematurely abort acorns as a means of maintaining adequate water and nutrition to the tree itself.