Island volcano in the city of sails
Off-track the ground is menacing. Lava, like angry waves frozen in mid-chop only moments ago, claws at the soles of my boots and threatens to shred my knees if I place a foot wrong. The surface is so uneven that progress is extraordinarily difficult. Occasional rills and channels course like petrified streams through the rougher ground, their solid surfaces a welcome pathway amid teetering plates of broken lava and treacherous bouldery rubble. Out of the shade of the dense thickets of bush, it’s as hot as a furnace. All that black rock absorbs and radiates enough heat to melt Antarctica. It’s as hostile a spot as you could find anywhere in New Zealand, yet when I turn around, there is downtown Auckland in plain view just a few kilometers away.
No landform is more familiar to Aucklanders than Rangitoto Island and yet how many of them ever go there? Its raking, symmetrical cone is a relaxed cousin of those more vertiginous volcanoes Taranaki and Ngauruhoe but Rangitoto is a truely astonishing wilderness right on the doorstep of the city. Landing on the island, the graceful sweeping curves seen from a distance quickly give way to a magnificent mosaic of the tortuous lava I’ve been scrambling through and scrubby, inpenetrable pohutukawa forest.
Of course, it was not always like this. The familiar form of Rangitoto did not exist for generations of Maori who first inhabited the lands surrounding the Waitemata Harbour. However, the emergence of the youngest and largest of the fifty-odd volcanoes in Auckland’s volcanic field, was witnessed by Maori living on adjacent Motutapu Island.
The persistent yelping of mangy dogs might first have awoken them. Soon afterwards a thundering roar and the vibration of the sandy ground beneath them would surely have jolted them from their whare. Outside, the familiar vault of stars above and the scatter of bright campfires along the shore to the west was hidden by a pall of steam, strobed by lightning and lit by a ferocious fiery glow from beneath.
A wind shift and the familiar smells of the camp—wood smoke, the sea, and even the penetrating stench of shark flesh drying on manuka frames—were soon overpowered by the pungent, suffocating odour of sulphur dioxide.
Running across the beach and dragging waka into the sea, shoals of dead fish bumped against their legs as they waded into the cold shallows. Paddling hard towards safety, the first wet ash began to fall, sticky and abrasive. Looking behind them, the cataclysm was becoming clearer in the first light of day, black clouds blasting out from the base of a roiling column of steam, flying boulders arcing white streamers through the sky and splashing into the sea.
Proof exists that in the weeks or months following the onset of the eruption, people came back to their campsite on Motutapu Island. The footprints of a small group of adults and children were found sandwiched between layers of Rangitoto ash. Markings show where the ground was prodded with sticks and that one of the dogs with the group paused to drink from a puddle. The impressions were so well preserved that the next blanket of ash must have spewed from the maw of Rangitoto soon after they were made. Whether these people were foolhardy or brave, lured by curiosity, or a desire to retrieve taonga, we’ll never know. One blazing summer’s day, I visited the site on Motutapu. As I rambled across hot dusty paddocks, sheep scattered before me. A scramble down a steep track cut into a siltstone cliff, and I was at a beach on the northern coast of Motutapu. Thick springy buffalo grass covers the flat behind the beach where archaeologists excavated the footprints in the ash. In the bank at the back of the beach, hunks of gritty grey volcanic ash slump and break off as the sea washes the loose sand beneath them. Low black cliffs where the khaki pohutukawa slopes of Rangitoto give way to the sea are just 1500 m away, the centre of the eruption only 3 km further. Beneath the ash deposits lies the archaeological detritus of the hunting, fishing, and stone tool making that went on at the site before Rangitoto erupted. Oyster shells, fish bones, and remains of fur seals, sea lions and wretched dogs—ubiquitous in prehistoric Maori settlements—indicate significant items in the broad diet of the occupants. More varied are bones representing over thirty species of birds—of which the most abundant remains come from kaka, tui, little spotted shags and kakariki. But among them are forlorn fragments of extinct raven and thrush, blue duck and artefacts made from moa-bone. Complete skeletal remains show some birds were eaten al fresco on site, while partial sets of bones indicate that others were preserved for later consumption. As elsewhere in New Zealand, the archaeological record on Motutapu shows that this bounty of forest birds in particular was not to last for much longer, and younger archaeological remains show an increasing reliance on seafood.
On Motutapu the effects of the Rangitoto eruption helped drive changes in land use. Ash from the volcano destroyed much of the forest not already burned and cleared by Maori on the island. The volcano was creative too—fertile new soil formed from the ash was eagerly cultivated to produce food for the population that flourished in the centuries following the eruption.
While humans undoubtedly witnessed the creation of Rangitoto, no oral tradition describing the actual eruption survives. It is highly likely the name Rangitoto, literally meaning “bloody sky”, originally alluded to the spectacle of the volcanic event. The word rangitoto is also sometimes used as term for rock of volcanic origin or rock that is particularly hard, such as the black argillite from D’Urville Island once prized for tool making, and enjoying a renaissance in boutique carved jewellery.
However, the traditional story behind the name for Rangitoto comes from the Tainui iwi. At a time when the Arawa canoe was moored at Orawaho (Islington Bay) it’s leader, Tamatekapua, got into a fight due to the unwelcome attention he had paid to the wife of the Tainui ancestor Hoturoa. Surviving the scrap, but bleeding profusely, his fate endures in the island’s full name— “Te Rangi I Totongia A Tamatekapua” or “the day the blood of Tamatekapua was shed”.
Walking over Motutapu, the ground couldn’t be more different from the harshness of Rangitoto. Blanketing layers of ash from the eruption have smoothed the topography. On Rangitoto lava surfaces—predominantly the rough, loose, loose a`a of Hawaiian terminology—result from the effusion of lava flows from fissures at the base of the summit cone. As the lava cooled, it contracted and fractured into rubbly blocks and plates. This was the last, but probably longest-lived phase of Rangitoto’s eruption. The lava flows extended the island to its present 23km2—a total larger than the rest of the Auckland Volcanic Field combined and graced it with its gentle lower slopes.
The early eruptions of Rangitoto were the most ferocious, driven by seawater flashing to steam as it encountered fresh magma at 1200 degrees C. Lasting just days, these phreatomagmatic explosions formed a low ash cone, now buried by the later products of the volcano, but known to exist from geophysical measurements.
Once sufficent ejecta had accumulated to seal seawater out of the vent, the eruption settled into a more constructive but no less spectacular phase of scoria cone building. Magma propelled by gas fountained from the volcano’s throat with great force, no doubt providing a pyrotechnic night-time display for Maori living around the shores of the Waitemata. The products of at least two phases of scoria cone building can still be seen in the summit topography of Rangitoto. The earlier phase forming the smaller outlying hills, the later the main summit crater and cone. Tainui later named these summit features “Nga Pona Toru a Peretu” or “the three knuckles of Peretu,” in honour of a celebrated ancestor.
At the end of the eruption, an intriguing moat-like structure formed, obvious when walking across the threshold from the lava flows onto the summit scoria cone. This was possibly the result of slumping of the summit area caused by contraction of cooling magma and collapse of empty conduits after the magma supply had run out.
One geological notion that has infiltrated local folklore in Auckland, is that Rangitoto was still active only 250 years ago. Bare expanses of lava on the island, selective quotes from historical accounts of the vegetation, and the vagaries of the Maori translation for “Rangitoto” have all served to confuse the issue. However, the main basis for a popular belief in eruptions continuing after Cook’s arrival is a piece of wood. In 1969, a sample of un-charred wood was collected from beneath lava on the eastern side of the island. From this, a carbon14 date of 225 +/-110 years was obtained at the Australian National University. Unfortunately, the sample couldn’t have had anything to do with the eruption. Had it been in contact with a lava flow, it would certainly have been charred or incinerated—basalt lava is fluid at about 1100 degrees C. Other carbon14 dates acquired from charcoal and shell from beneath Rangitoto ash on Motutapu reliably place the eruption at around 1400 AD.
Ian Smith, a geologist at the University of Auckland, told me that new evidence may shed light on the time it took Rangitoto to form. He and his colleagues are analysing core samples taken from the bed of Lake Pupuke and have found ash, or tephra, from Rangitoto in them. While the results are preliminary, Smith says the thickness of accumulated sediment lying between the two layers of Rangitoto tephra present in Lake Pupuke suggest ten to 100 years elapsed between the ashfalls, which arose from separate eruptions. Smith’s main interest in the volcano is the origin of the magma, and what that might portend for future eruptions around Auckland. “The chemistry of the older tephra layer found at Pupuke is associated with the ash on Motutapu and scoria from one of the older outlying cone remnants near the summit. It came from a smallish deep-seated eruption perhaps equivalent to Mt Wellington in size. The composition of the younger tephra is more similar to the later lava flows. It seems that at Rangitoto there was a later, much larger eruption associated with extensive melting of rock at shallower depth. This may represent a change in the way the whole Auckland field is operating. Rangitoto produced much more lava than any earlier Auckland eruption and future eruptions might also involve shallow melts and larger volumes of lava.”
The Plant Colonisation of the inhospitable lava fields of Rangitoto has long been a source of fascination and debate among visitors to the island.
Thomas Kirk was one of the first botanists to describe the vegetation. Kirk held a string of distinguished positions in the early botanical community of New Zealand, and it was said that no other botanist ever acquired such a complete familiarity with the flora of the colony. This description he wrote in 1878 still holds today:
“The volcanic island of Rangitoto . . . possesses greater interest to the botanist than any other island in the [Gulf]. This arises less from a copious flora—although the number of species is comparatively large—than from the remarkable state of the ligneous (woody) vegetation, which exhibits the utmost luxuriance of foliage and flowers on the most diminutive specimens, and from the peculiar conditions of growth, most of the plants springing directly from the face of the rocks or the crevices between them.”
Biologists have more recently described Rangitoto’s pohutukawa forest—the world’s largest—with a term straight from a B-grade movie: a “hybrid swarm.” The predominant trees of the island are not true pohutukawa, but rather hybrids between Metrosideros excelsa, pohutukawa, and Metrosideros robusta, northern rata. More rata-like trees—with smaller flowers and glossier leaves—growing on the eastern side of the island suggest that the ancestral source of rata was somewhere to the east.
Botanically, Rangitoto is a striking example of primary succession—the colonisation of new land by plants for the first time. The lava on Rangitoto is challenging environment for plants to establish—the ground is porous and dry, with no soil, and summer surface temperatures can reach 70 degrees C. The vegetation ranges from a tenuous haze of lichens and moss on bare lava, through scrub on the summit scoria cone, all the way to lush pohutukawa forest. The pattern is tied to the basalt rock surfaces, with more developed pohutukawa forest at the edges and hollows of lava flows where most moisture collects. Some 200 species of native plant including 40 species of fern have now found their way to the island.
The forest colonisation of Rangitoto has had hindrances apart from rocks. Herds of goats plagued the island in the 1800s and faded copies of the New Zealand Herald record fires burning there, including one in 1887 that continued for over a week. The reported habit of visitors to the island lighting fires to signal to friends how far they’d climbed may have contributed to the problem. Exploring just metres into the forest from a bare lava flow, I’m soon thwarted by dense sprawling tangles of silvery Astelia leaves. My exertions shake a dusting of crimson anthers from pohutukawa flowers onto the thick cushion of milky green moss below. Although progress through the profuse undergrowth is frustratingly difficult, it makes me realise that the forest is probably healthier than at any time since Kirk wrote about it.
Since 1990, when the Department of Conservation eradicated an herbivorous horde of possums and wallabies, the vegetation of Rangitoto has undergone a major resurgence. The animals invaded the island soon after one Robert Graham had introduced them to Motutapu when he farmed there around the 1860s. A friend of Governor George Grey, whose one-time menagerie on Kawau Island is renowned (see NZ Geographic #39), Graham also introduced deer, ostriches and other exotic animals in the hope of attracting visitors to Motutapu.
Serious possum damage to pohutukawa trees had a dire effect on the yield of the exquisite white honey that had been produced on Rangitoto since 1926. From an average of 42 kg per hive before 1985, honey production was reduced to just 7 kg per hive by 1990. The possum control that year resulted in a flush of new growth on the trees, and by 1995 each hive on the island was averaging 55 kg of honey a year.
Threats to the ecology persist in the form of rats and stoats, and (ironically) in the weeds that are flourishing in the absence of browsing animals. Of the 250 non-native plant species introduced to Rangitoto, evergreen buckthorn—spread by birds that gorge on the red berries it produces—is now the worst weed. I don’t envy the DoC weed team whose job it is to slog over the rugged terrain in the battle to control the invaders.
My grandfather owned a 32’ yacht called Scout that he used to bring down to Islington Bay. He and his friends took young ladies for weekend cruises, but in those days, overnight stays were frowned upon. So they built the bach for the ladies to sleep in, and the men stayed on the yacht.” Telling me this over a cup of tea on the sun porch of his bach at Islington Bay, Bryce Ellis is quietly spoken, but his grin and the glint in his eye suggest this wasn’t always the case.
Ellis told me that the cream–coloured bach, with its red roof, was built for his grandfather, William Ellis, in 1922 by Harry Langley. Langley was also one of the first to produce honey on the island—at one stage reputedly, by appointment to the King. Bryce Ellis has been coming to the bach since 1928 when he was just three weeks old. “We used to come on “Snorkie” Inglis’ Olive boats: Olivene, Olive Jean, Olive Rose. They used to run every day, twice a day, like clockwork.” The ferries to Rangitoto wharf don’t serve Islington Bay regularly, so these days Ellis and his wife Anne get to the bach on their own launch.
“In the old days people poured down to Isi’ Bay for six weeks at a time over summer. My cousins would come up from Putaruru to stay. As kids, we all learnt to row and sail a P-class yacht out in the bay”. Swimming and fishing were daily activities. “One day a school of kingfish got caught in the shallows, so we all rushed out with knives attached to poles to spear them.”
The Ellis’s bach is one of 121 that were built on Rangitoto between about 1920 and 1937 when it was decreed that no more would be permitted. Like most, the bach is nestled among pohutukawa trees, and faces resolutely towards the sea. Ellis points to a distorted doorframe, the architrave skewed to fit a ship’s cabin. “That’s from the Ngapuhi. As kids we used to go over to Boulder Bay and had great fun playing on the wrecks.” The steamer Ngapuhi was one of thirteen vessels that met an ignominious end on the rugged north-eastern coast of the island between 1887 and 1947. Deliberately wrecked for disposal, the hulks provided an eclectic assortment of building materials to augment the typical timber and corrugated iron construction of the baches.
Just 34 of the baches still stand; thirteen near Islington Bay, eighteen around Rangitoto Wharf, and a further three at McKenzie’s Bay at the western “Beacon End” of the island—dubbed for the 116-year-old red and white striped Rangitoto Beacon. While rising beachfront property prices elsewhere drive the replacement of traditional kiwi baches with palatial holiday homes, the baches remaining on Rangitoto are now considered cultural treasures.
Architecturally, Rangitoto’s baches cross do-it-yourself improvisation with touches of the California bungalow fashion of the day. Although their virtues might be less apparent than contemporary buildings like the Auckland War Memorial Museum, or the Art Deco buildings that sprang up in the wake of Napier’s devastating 1931 earthquake, they still preserve some of the style of the era. And like Napier’s Art Deco treasures, they too might not have existed at all except for a twist of fate, albeit one of governance rather than geology.
The island was purchased by the Crown in 1854 and in 1890 designated as a public domain, administered by the Devonport Borough Council. Rangitoto was a popular destination for picnic parties from Auckland. In 1897, the opening of the first “Pioneer Track” to the summit attracted 2,500 people to the island.
Strapped for cash to develop facilities on Rangitoto, and facing a revolt from Devon-port ratepayers against a levy to cover the work, the Council decided in 1911 to lease “camp sites” at £4 a year to raise revenue. In an era of poor roads and few cars, when distant holidays were beyond the reach of most, the opportunity to get way from it all so close to Auckland was embraced enthusiastically. From the 1920s, baches started dotting the coast as leaseholders built their own islands of comfort among the inhospitable lava fields.
Nearly as soon as the bach building had started, it became apparent that the Council had overstepped its powers, and that private baches on the public reserve were in fact illegal. Thus began a series of decrees, petitions and reprieves for the baches that continues to the present day. In 1937 the government ordered the baches to be removed, but later allowed a period of 20 years before they had to be demolished. In 1953 the Minister of Lands issued a non-transferable lifetime lease to those who could prove ownership of the baches. As lessees died or surrendered their leases, the Hauraki Gulf Maritime Park Board and subsequently the Department of Conservation demolished the baches. In 1991 a moratorium was placed on further demolition to allow the cultural and architectural values of the baches to be appraised.
Although the future of the baches was never assured, it proved no obstacle to the growth of thriving communities of holidaymakers. Like other clusters of baches on New Zealand’s coast at Taylor’s Mistake, Bayly’s Beach, or Wellington’s south coast, families returned for weekends and an extended stint over the summer to swim, catch fish, celebrate and relax together.
Prisoners brought from the Mt Eden prison quarry to build roads between 1925 and 1934 also built facilities for the bach communities. Generations of children were taught to swim in a tidal swimming pool constructed near the Rangitoto wharf, while over at Islington Bay, a hall and tennis courts were built largely with funds from the bach holders.
Holidays at the baches were restricted for a time during WWII. The few squat concrete buildings around the summit are the remains of observation and fire command posts, and later radar, constructed to direct fire from gun batteries on Motutapu and other sites. Constructed at enormous expense, operation of the facilities at the summit was short-lived due mainly to difficulties with water supply and Rangitoto’s arduous terrain. At Islington Bay, a base was constructed in an old Harbour Board quarry to service minefields protecting the approaches to Auckland.
Near the old swimming pool I meet Alan and Shirley Collins who invite me back to their bach—one of the island’s oldest. Barely a four-roomed affair, it’s the sort of place where growing children returning on holiday each year must have felt the tiny bedrooms were shrinking. Over tea and cake, Shirley recalls their kids spending all day at the pool in the 1960s, with their hair turning blueygreen from the bluestone used to treat the water.
Facilities at the Collins’ bach include tank water plumbed to the kitchen sink and an ancient kerosene fridge whose emanations have blackened the walls and renders the air astringent. A corrugated iron hut outside the back door provides an open fireplace for cooking.
Alan Collins, a retired panel beater from Otahuhu, tells me, “Though we’ve been coming here continuously since 1961, I first came up here in 1944 at the age of 8 or 9. Back then the house was out in the open, and there were roses planted all around it.” Now, pohutukawa branches reach right over the roof, fallen leaves adding a certain tang to the drinking water.
Since the baches were assessed for their architectural merit, officialdom has begun to agree with the refrain of bach owners and enthusiasts who have long lobbied for the protection of the remaining baches. In 1997 the New Zealand Historic Places Trust registered the three groups of baches as Historic Areas. The same year, the Rangitoto Island Historic Conservation Trust was formed to “conserve and interpret the historic bach communities on Rangitoto Island for the benefit of all New Zealanders.” Next door to the Collins’ bach, work is underway on the first of three baches that the Conservation Trust is restoring with the help of substantial sponsorship from AMP Financial Services.
Sitting at the Collins’ dining table, we’re close enough to Rangitoto wharf to see the ferry arrive, and it’s time for me to leave. I stroll along the shell path beneath tangled pohutukawa branches to join the throng of day-trippers boarding the boat for the short trip back to the city. The Fullers ferries bring 2000 people to the island on a summer weekend day like this. Sooner than it takes to finish a cold drink, we’re slowing down to dock at the downtown ferry terminal. The Sky Tower looms like a hypodermic jabbed into the city skyline—no competition, I think, to Rangitoto as the symbol of Auckland.