The origin of the dune ridge is not known, but it might have started as a foredune that grew in height and became stabilized by vegetation.

There are several indications that the dune ridge is older than the active foredune. A greater variety of vegetation shows that there has been time for secondary species to move into dune areas first stabilized by pioneering dune species like American beachgrass. The trees in open and forested dune ridge areas needed a number of years to reach their current sizes.

In 2004, treecores of four cottonwoods on the open dune ridge indicated minimum ages of 25-40 years*. Cores from trees on the forested dune ridge indicated minimum ages of 50-150 years. The dune ridge must be older than the ages of the trees on it.

*Study by J. Zirkle in summer 2004 (see Publications list).