Ihumatao: fossil forrests next to Auckland Airport


The remains of two fossil forrests can be found on the foreshore and in the cliffs at Ihumatao.


There are two fossil forests at Ihumatao both destroyed in different circumstances over a period of 100,000 years.

The oldest a mature Kauri forest had trees varying in diameter from  from 70 centimetres to3 metres. Some of the fossil Kauri trees must originally have been giants rising more than 20 metres into the air before branches sprayed out. What killed the first forest?

It was probably a slow death. Logs and stumps from this forest are found in thick peaty sediment. This may have occurred through natural swamp formation in the area with the forest slowly drowning. Logs and stumps are exposed in cliffs at the top of the beach and on the foreshore where the dark sediment has eroded.

Over time the conditions that produced the swamp changed and the land dried sufficiently for another forest to flourish. Trees found growing in this rich peaty soil included rimu, miro and hinau. About 50,000 years ago disaster struck again. Nearbye Maungataketake exploded into life. Yellowish to brown volcanic ash rained down on the trees  stripping leaves from branches and branches from trees. The explosive force of  eruptions snapped trunks in two. The remains of the forest was buried in ash and lava bombs .

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