Dust on My Feet: A Walk in the New Zealand Rainforest

The bush grows dark, dank and mysterious. Trees and shrubs tumble around, over and under each other in an impenetrable barrier. This is the typical New Zealand native bush, which is in fact rainforest, quite different to what the Australians call ‘bush’.

New Zealand has many different types of ‘bush’, as the country extends from the sub-tropical to the temperate zones of the Southern Hemisphere. In Orewa, just a few hundred metres from where I am writing this, is Alice Eaves Scenic Reserve, a small relic of the original coastal rainforest near Auckland city. The forest here is primarily of stands of nikau palms, large gnarled hardwood puriri and small healthy stands of young kauri, the giant tree of North Auckland which was decimated for its excellent timber in the 19^th and first half of the 20^th centuries.

Nikau palms & ancient puriri trees in Alice Eaves Reserve, Orewa

In Northland there are still a few areas of the original dense rainforest where the giant kauri trees still flourish. Te Matua Ngahere, a forest giant with a girth of over 16 metres, resides almost unseen in the dense sub-tropical Waipoua Forest.

The ancient giant kauri tree, Te Matua Ngahere, 'Father of the Forest', Waipoua

On the West Coast of the South Island there are the swamp-forests where the predominant tree is the kahikatea, the New Zealand white pine, often referred to as the dinosaur tree as this species is said to have changed little since the age of the dinosaurs. The swampy vegetation surrounding these trees adds to the primeval atmosphere.

Swamp forest at Ship Creek, Westland

In the higher more temperate country of the South Island are the beech forests, the ancient nothofagus species whose ancestors had colonised much of primeval Gondwanaland, and now exist naturally only in parts of Australia and South America. These are no relation to the beech trees of the Northern Hemisphere - fagus spp.

Southern beech trees in the temperate rainforest at Makarora, Otago

With the lack of browsing mammals, the New Zealand forest can grow extremely dense, with clumps of the twisted liana vines known as supplejack, making the bush all but impenetrable. The bright red summer berries of the supplejack, along with those of the karamu, were a source of bush-food to the pre-European Maori. The karamu is of the Coprosma species whose Latin name means, to use the vernacular, 'smells like shit' ... or dung in polite society, which shows that some botanists did have a sense of humour! One of the species, Coprosma foetidissima, known to the Maori as hupiro, was called stinkwood by Europeans, hence the name for the entire family.

A tangle of supplejack - Ripogonum scandens - an the red berries of the karamu - Coprosma robusta

While the New Zealand rainforest lacks mammals, with birds and insects also being very scare, there is an abundance of interesting smaller plants which the average bush-walker can easily overlook. Flowers can be small and many are white, catering for the large numbers of night-flying moths - native butterfly species only number around 15.

The beech forests harbour some interesting specimens. In some areas a thick black sooty mould covers the bark of certain beech trees. Closer inspection will reveal thin tube-like apendages protruding through the mould, secreting tiny droplets of honeydew, These are the anal tubes of a primitive scale insect which feeds on the sugary sap of the tree. The sooty mould grows on the discarded honeydew. Other insects, particulalrly the introduced wasp and native birds in turn feed on the honeydew, an important link in the forest food-chain.

Also in the beech forests, particularly in the Spring or early Summer, the so-called beech strawberries appear. These are a parasitic fungus, Cyttaria gunnii, that appear on some of the smaller brachlets of the beech trees in temperate areas. They are not always obvious, except when the yellow honeycomb-like fruiting bodies have fallen to the forest floor.

Scale insects anal tibes with droplets of honeydew, & the fruiting bodies of beech strawberries.

While the New Zealand rainforest is normally regarded as being benign to human intruders - no ferocious mammals, snakes, scorpions, and even a lack of biting insects - there is a lurking hazard for some of the lower insects. This is the stuff of nightmares, something out of a Kafkaesque dream. Several species fungi take over the bodies of living insects, feeding on or altering the structure of the victim. Best known is probably the awheto, or vegetable caterpillar - Cordyceps robertsii - in which the fungus will perfectly retain the shape of its victims. This unfortunate was also used as a tattooing pigment by some Maori tribes. While I have never found the awheto in the forest, I have come upon its close relative, the vegetable cicada - Cordyceps sinclarii. This fungus will attack a buried cicada nymph, feeding on its tissues. An indicator is white, powdery fruiting heads in the forest undergrowth and when uncovered, the remains of a cicada nymph becomes visible. Another of these parasitic fungi is the sugar icing fungus that will attack living cicadas, stick insects, mantids, and wasps, coating the vunerable parts of the body with 'icing', while it feeds on the unfortunate insects internal organs.

The vegetable cicada - Cordyceps sinclarii - fruiting bodies among liverworts, & an exhumed nymph

Finishing on a less macabre note, in certain areas of the forest is found the giant moss, Dawsonia superba, which is one of the world's largest mosses. The first time I found this, was in the Coromandel rainforest. I was with an American botanist. She looked at the plant, stood back and said: "it can't be." I looked at her, somewhat puzzled. She said "it looks like a moss, but is far too large." A few days later I received a fax with the moss identified as Dawsonia superba.