About 10 years i think but i could be wrong...
An oak tree, depending on variety,can take 2 to 300 years to reach maturity.
there's no such thing as an "acorn tree", acorns grow on oak trees...
An acorn falls off of a mature oak tree.This acorn germinates. Soon after it begins to grow and produces small leaves.The leaves gradually mature, and in about 20 years it produces it's own acorns, which are ready to repeat the cycle.
Please see related link below.acorns
An acorn
An acorn is the nut of the oak tree.
early spring and late summer
How long is a piece of string. This depends on when the acorn sprouted.
An acorn is not a tree it is the fruit of the oak [Quercus] The oak is hardy.
I have a mature tree with thorns over 3" long.
a tree nut
The acorn grows into an oak tree.
You grow an acorn tree!