The Kauri dams of Aotea.

In 2014 there was a massive storm that hit the oldest kauri dam on Aotea. It was 110 years old and destroyed it. But what it did was bring some attention to the old logging industry that thrived last century, and the century before.

As a result of the aggressive felling of the native forest, mānuka and kānuka thrived. These trees are known as colonisers as they are the first among the natives to grow, and they grow quickly! Spreading their branches to erect a canopy to protect the undergrowth which allows the ponga, koromiko, kauri and many other native plants to grow and put down their roots. Kauri for example take hundreds of years to grow and mature. There is an amazing biochemistry and synergy that has gone on for millions of years in Aotearoa.

Kauri dams have been a big part of the history of Great Barrier Island’s kauri felling and timber industry. The Kaiaraara dams transported some 90 million feet of timber down to the Kaiaaraara River Mouth by the sea. This was a huge chunk of the island’s forested landscape, and left it raw and smarting. Today, conservation efforts to restore the kauri stands are in action.


The Kaiaraara dams were built below Hirakimata (Mt. Hobson). There were three large dams based on the trapdoor system, which involved a horizontal slat, attached to vertically placed planks, which swung open when the river pressure mounted under the force of a flood from a storm. The largest of them was built into solid rock, to maintain the massive strain.

Kauri trees, which are the largest trees that grow in New Zealand, with maximum heights of 50 metres and maximum widths of 10 metres, produce a really solid, straight and durable timber, which floats.

Naturally, māori had seen it as an immensely useful tree, and it wasn’t long before colonisers realised the utility in the kauri. Māori used the kauri timber for building waka and whare, and for whakairo. They used the kauri gum as fire-starters. Pākehā sailors used the timber for ships’ masts and spars, and Pākehā settlers used it for building really strong log houses.

But the history of kauri use on Aotea Great Barrier Island is convoluted. To start with, Port Fitzroy was the site of the first kauri timber work in 1794. A sawmill was built almost 100 years later at Bush’s Beach in Kaiaraara Bay in 1890. In 1901, the Kauri Timber Company built Whangaparapara Mill to process kauri from the mainland. In 1914, the mill closed down. Logging resumed in 1926.

Stands of kauri previously considered inaccessible due to their remoteness and the steepness of the slopes they grew upon were pounced on, as the dams moved into action. These eroded the valley and contributed to the development of a broad silt deposit at the river mouth. Kauri timber work is difficult, tough and comprises of long days. The immense size of the logs makes it dangerous work. But the rewards were great. Not only was the timber always in demand but there was great utility in the gum that was used as resin and as a fire starter. 

Although the industry has long come to an end, it gives us great pride in learning just how special the native trees and plants are of this country. Both for their remedial benefits as well as their function in design as posts and pillars. They had 100s of millions of years to develop their unique properties and DNA, on an island in the subtropical waters, that was the last land mass, other than Antarctica, to be discovered.