Lake Ohia Gumholes Reserve

When is a lake ephemeral, and when is a forest a swamp? When it is ancient Northland kauri forest in seasonal wetlands, dug over for precious gums, and the water drained along the way.

Lake Ohia on the way to Karikari peninsula is the poster child for viewing this phenomena, because it is accessible from the road and has been formed into a DOC Reserve. Geologists are interested in it too, as the processes which created the ephemeral (seasonal) lake and petrified the Kauri took place over many thousands of years.

The lake, which used to be wet all winter is now only wet for two months of the year. It is still muddy but this does mean it is easier to access and view the interesting holes left by the stumps of the formerly petrified Kauri Trees. DOC have put in some boardwalks, picnic areas and information boards. Visitors should also see mudfish, plenty of birdlife and regenerating bush.

An interesting but sad link to far-away Hawaii is that the Big Island is facing the extinction of the Ohia Tree, a relative of the New Zealand Pohutukawa Tree. Disease is killing the Ohia in similar way to the Kauri dieback which is threatening the remainder of New Zealand's Kauri Trees. There also used to be a lake called Ohia on the Big Island but this has also disappeared.

Image Credits: Auckland Libraries Special Collections, Auckland Weekly News 01 May 1913

"An unexpected supply of Kauri Gum: Natives carting gum from the bed of Lake Ohia, near Mangonui, North Auckland. The recent summer has been one of the driest in history of New Zealand. The far north of the Auckland Province has been especially favoured in this respect, and deposits of Kauri Gum have been recovered from spots which previously have been inaccessable. Lake of Ohia, for instance, has been so dry that gum has been taken from the bed which in winter is covered with several feet of water. The lake covers an area of some square miles, and the unexpected dryness has enabled the native gumdiggers to make a rich haul."