Fibonacci tree branching splits asymmetrically. A Fibonacci sequence results because branches must mature before splitting, resulting in asymmetrical branching, the most common tree pattern seen. Botanists call this type of branching “sympodial-monochasium.”

A fractal is a pattern that repeats at smaller and smaller levels. All these trees are fractal because, regardless of the particular type of dividing, the pattern of branch splitting repeats for smaller and smaller branches. For example, a bifurcating tree splits into two branches, then each of those branches splits into two, smaller and smaller.