Lake Ohia Kauri Swamp

The dense Kauri Forest lived about 30 000 years ago and was killed off by natural processes. Subsequently the area bacame an ephemeral lake (dry in summer but water-filled in the winter). It is a significant historical site that was dug over for Kauri Gum by hundreds of workers in the late 19th Century when kauri gum (fossilised resin) was valued highly for making varnish. The gum diggers drained the lake back in their day, so it no longer forms as it did before they arrived.

You can see the stumps of many large kauri trees and the occasional small piece of resin that is recogniseable due to its characteristic odour. It is worth exploring to appreciate the size of some of the stumps and to imagine how the forest would have looked when it was thriving. The trees were alive during the last ice age, when the sea level was a lot lower, and the sea would have been much further away than at present. Interestingly, there are swamp kauri all over the Northland region that died at about the same time, i.e. about 30 000–35 000 ago. Have a think about why the trees may have died. Kauri are shallow rooted and prefer dry soils, so water may well have had something to do with their demise. Apart from a change in the ground water, what else could kill off a forest?
The area is now a valuable ecological site for rare plant species as well as for the mud fish that lives in some of the muddy pools.