Mount Pirongia
Mount Pirongia is an extinct stratovolcano located in the Waikato region of New Zealand's North Island. It rises to and is the highest peak around the Waikato plains. Pirongia's many peaks are basaltic cones created by successive volcanic eruptions between the late Pliocene and early Pleistocene, about 2.5 million years ago. In the adjacent picture, the characteristic profile of the mountain can be seen, along with a prominent accessory cone to the right.
History
The Māori people of the Tainui waka have strong whakapapa-based links to Mount Pirongia. The mountain was first encountered after landfall of the Tainui waka around 800 years ago. Early names bestowed on the mountain included Paewhenua and Pukehoua. The present name is:"Te Pirongia o Te Aroaro ō Kahu", which translates to 'the putrid stench of Kahu', or more gently, the 'scented pathway of Kahu'. This name originates from Kahupekapeka, who following the death of her husband Uenga, left Kāwhia with her son Rākamaomao and travelled inland, naming many peaks across the Waikato region. Kahupekapeka searched the bush on Pirongia for rongoā rākau to heal her body, which was afflicted by the miscarriage of her unborn child with Uenga.To preserve the heritage of Mount Pirongia, Pirongia Te Aroaro o Kahu Restoration Society Inc was formed in 2002 as a result of deep-seated community interest in its ecological restoration. During 2001 DoC had invited nominations for a working group. The Society evolved from a hui at Pūrekireki Marae on 20 April 2002. The Māori people have a strong connection to Mount Pirongia.
On 18 December 2024, the name of Pirongia's second tallest peak, The Cone, was formally changed to Pūāwhē by the New Zealand Geographic Board.
Geography
Mount Pirongia is located to the west of Te Awamutu and from the small settlement of Pirongia, and lies in the Pirongia Forest Park. It is clearly visible from the Tasman Sea, being just from the coast at Aotea Harbour.Geology
Mount Pirongia is the largest stratovolcano in the Alexandra Volcanic Group chain which extends inland from Mount Karioi near Raglan. It is a mainly basaltic volcano, though andesite dykes form the peaks of Wharauroa, Mahaukura, Tirohanga, Pirongia Summit and The Cone. To the west it merges into the highland terrain of the Karioi horst block and in the east it arises above the Hamilton Basin, a major rift-related depression bound by the Waipa Fault Zone. There are at least six edifice-forming members separated by features including those resulting from large volume collapse events. The largest debris avalanche cascaded at least 25 km southwest from Pirongia into the Kawhia Harbour and was larger in volume than the Mt. St. Helens collapse of 1980. The collapse was followed by late-stage eruptions from the summit area around 1.6 Ma. The mountain contains unusually crystal-rich lavas of that also occur on Karioi, Kakepuku and Te Kawa but are not found elsewhere in New Zealand.| Time | Deposit name | Comment |
| 1.60 ± 0.04 Ma | Pirongia | Current summit, also peripheral basaltic eruption 1.64 ± 0.13 Ma on flanks |
| Approx. 1.65 Ma | Oparau | Collapse volume |
| Approx. 2 Ma | Hiwikiwi | Collapse and peripheral basaltic eruption 2.03 ± 0.03 Ma |
| 2.25 to 2.13 Ma | Hiwikiwi | 2.30 ± 0.005 Ma Hikurangi |
| 2.35 ± 0.2 Ma | Ruapane | |
| 2.396 ± 0.005 Ma | Mahaukura | Mahaukura edifice. Central vent is Tirohanga Peak, which is andesitic, as are Mahaukura Bluffs. Ruapane Peak is ankaramite. |
| 2.54 to 2.418 | Paewhenua |
Land use
Mount Pirongia is a popular place for hunters from Hamilton seeking a quick day trip hunt, holding several feral goat herds on its bush-clad slopes. Rumours abound about small numbers of red deer released by farmers after an earlier deer farming boom went bust. Pirongia Forest Park is administered by the Waikato DoC office in Hamilton.Ecology
Threatened plants include king fern, carmine rātā, thismia rodwayi and Wood Rose or Dactylanthus taylorii, a rare and endangered parasitic flowering plant, found on the ridges of Mount Pirongia. Near the summit there are mountain flax, coprosmas and ferns. Botanically, Mount Pirongia is also interesting area as it marks the transition between the warmth-loving kauri forest of the north and the beech and podocarp-beech forest in the south. The park's latitude is the naturally occurring southern limit for kauri, mangeao, mairehau, tāwari and taraire.The canopy in the podocarp forest of the lower slopes is tawa, with scattered rimu, kohekohe and a few other trees. The subcanopy has tree ferns, including wheki and ponga, and nikau palm, with pigeonwood, hīnau, pukatea, supplejack, māhoe, hangehange, kanono and toropapa. Rātā replaces kohekohe at higher levels, until a change to upland forest at about. Above that, kāmahi, tāwari and tawheowheo become more prominent until at tawa is very rare. Above there are also scattered Hall's totara, miro, rātā and horopito, and, near the summit, pāhautea, but no rimu. Rocky summit pinnacles have the sub alpine species snow tōtara and eyebright .
Commonly found birds are: pīwakawaka, kōtare, tūī, kererū and kārearea. In 2019 funding was won for reintroduction of kōkako.
Pest control
and goats have been controlled since 1996, brown and black rats since 2006 and mustelids since 2019, using traps and goat, deer and pig hunters. About 1,000 goats were culled in 2021-22. 1080 drops in 2007, 2014 and 2020 were effective in reducing possum numbers. The Pirongia-aroaro-o-Kahu Restoration Society has a network of bait stations on the north east side of Pirongia.Recreation
Tracks
Summit tracks
There are numerous tracks to the summit. All the tracks are well signposted, with bright orange plastic waymarks and near the summit have recently been laid with boardwalks, some of them as part of Te Araroa long distance trail. A lookout platform was built on Pirongia summit after 1999. From it, it is possible to spot Mount Taranaki summit and Mount Ruapehu summit on a clear day. On the west side there are Aotea, Kawhia and Raglan harbours.- Mahaukura - Tirohanga Circuit is a longer distance but with a gradual climb from Grey Road. This track is considered difficult. It leads through many steep sections but gives excellent views from Wharauroa lookout, the last to it having a fixed chain to assist climbing, Mahaukura peak and Tirohanga peak. In winter and after rain the track becomes muddy and slippery. There are many narrow sections with a tangle of tree roots and rocks.
- * Wharauroa Track is an alternative route to Wharauroa lookout, which is shorter and about less to climb. It starts over farmland at O’Shea Road, before climbing through tawa bush.
- Tirohanga Track starts at Corcoran Road, climbs to Ruapane, skirts the hornblende andesite dike of Tirohanga and undulates with some chains, before merging with the Mahaukura Track.
- * Ruapane Track, a longer alternative route to Ruapane, starts at Waite Road.
- Bell Track via Kaniwhaniwha Caves starts with the Nikau Walk from Limeworks Loop Road. It stays in the valley to the kahikatea recorded as the tallest native tree at, then climbs to a series of clearings, one with a campsite. Beyond it is very muddy, as it climbs to the ridge and the Cone and then passes Pāhautea Hut to the summit.
- Tahuanui Track also starts with the Nikau Walk from Limeworks Loop Road. It climbs steadily beside the Kaniwhaniwha valley, before a short descent and ascent to join the Tirohanga Track to the summit.
- Hihikiwi Track climbs many steps in bush from Pirongia West Road, then rises further to an up and down ridge, to reach Hihikiwi Lookout, where there are views down the Ōpārau valley to Kawhia Harbour. From the lookout there is a boardwalk and steps down and up to the hut.
Lower tracks
There are also lower level tracks -- Corcoran Road Lookout a short, wheelchair accessible track, in bush to a viewpoint.
- Mangakara Nature Walk views examples of miro, tawa, rimu, kahikatea, mahoe, rewarewa, kareao, pukatea, nikau and kāmahi bush.
- Nikau Walk like the Bell and Tahuanui Tracks, this walk starts at Limeworks Loop Road, passes through an area planted around 2010, then follows the Kaniwhaniwha stream to a nikau palm and tree fern fringed loop walk. A further 30 minutes of walking allows a visit to the long Kaniwhaniwha Cave, through the limestone.
- Ōpārau Route from Pirongia West Road is unmarked and crosses farmland to the park boundary. The Ōpārau River is unbridged and impassable after heavy rain.
- Walter Scott Reserve was given to the Waikato Branch of Forest and Bird in 1963 and gazetted as a reserve in 1966, but has since had its surrounding bush converted to farmland. The reserve has tawa-kāmahi forest with pukatea, miro and king fern.