Mangawhai Sandspit is thought to have been mostly covered with forest 1000 years ago. Remnants of burnt tree stumps are still visible. Sand migration appears to move in a north-west direction and sands are deposited on the sandspit by wave and wind action. During storms large volumes of sand were blown off the sand dunes and into the Harbour - an event which could not have occurred 1000 years ago.
Windbreak fences were built along the sand dunes to collect the wind blown sand drifts.
Naturally occurring plants such as Pingao and Spinifex were planted between the fences to further stabilize the sand and introduce organic material to the dunes.
Where once there were no sand dunes, waves and wind ravaged the shoreline. Planting has helped build up sand dunes to, in places, six and seven metres high.