Aotearoa / New Zealand plants have been treated as an endemic species, Planchonella novozelandica, merged into P. costata or referred to as Pouteria costata (Green 1990) and then reinstated as Planchonella costata (Swenson et al. 2007). The generic placement in Planchonella is accepted by Australian botanists and it is used here.

Planchonella costata is a large tree, indigenous to Aotearoa / New Zealand where it occurs on Ika a Maui / North Island (Manawatawhi / Three Kings Islands), Te Paki, Te Aupouri, Northland, Hauraki Gulf islands, Aotea / Great Barrier Island, Coromandel Peninsula, and associated islands, Waitakere Ranges, Kawhia Harbour, Bay of Plenty - Tuhua / Mayor Island, Tairawhiti / East Cape. It also occurs on Norfolk Island (type locality). The size of the subpopulation in New Zealand is suspected to be more than 15,000 mature individuals, with most of these being secure on predator free islands where there is ample recruitment. There is ongoing loss in sites where browsing animals are not managed. On Norfolk Island the species is considered uncommon with a suspected subpopulation of 500–1,000 mature wild individuals. The area of occupancy is estimated to be less than 2,000 km² but the species occurs in more than ten locations. It is assessed as Near Threatened.

This species is indigenous to Aotearoa / New Zealand where it occurs on Ika a Maui / North Island (Manawatawhi / Three Kings Islands), Te Paki, Te Aupouri, Northland, Hauraki Gulf islands, Aotea / Great Barrier Island, Coromandel Peninsula, and associated islands, Waitakere Ranges, Kawhia Harbour, Bay of Plenty - Tuhua / Mayor Island, Tairawhiti / East Cape. It is also found on Norfolk Island (type locality). Distribution map is generalised.

No nation-wide accurate counts of individuals have been made for this species. The species was treated as a ‘Relict’ by de Lange et al. (2018) with a national population range estimated at 5,000–20,000 mature individuals (a national total of >15,000 seems likely). This assessment was based on the fact that the largest viable populations in Aotearoa / New Zealand are found on secure, predator-free offshore islands that are mostly Nature Reserves with strict permitted landing only. Outside these islands, Planchonella costata is known from coastal forest, along portions of the Te Paki, Te Aupouri, parts of the eastern Northland Peninsula, the Waitakere Ranges, Coromandel Peninsula (and near shore islands), Tairawhiti / East Cape, and from a single tree on the shore of the Kawhia Harbour. Some of these locations are managed as mainland islands – so virtually free of browsing animals. Outside these areas, and on some of the near shore islands without active management the species persists as isolated trees or stands, with little or no recruitment. Collectively though, these sites probably account for <5% of the species viable range in Aotearoa / New Zealand. In Aotearoa / New Zealand the species national population is now considered stable, or slowly increasing.

On Norfolk Island Planchonella though present, is considered uncommon (Green 1994) but when viewed by the author in 1998 seemed secure in its habitats, though with little regeneration, with an estimated total population of 500–1,000 mature wild plants.

Although the longevity of the species is unknown, Planchonella costata is probably long lived, maybe in excess of 300 years on the basis of historic images and unpublished ring counts. At a national level most of the decline has now happened historically, so a decline rate <5% over the next three generations seems likely. Outside those areas where threats cannot be controlled, the species is recovering such that as a whole the total population of this species can be considered to be increasing.

The situation of Norfolk Island is, however, unknown, the species is considered uncommon there (Green 1994) and there was little recruitment evident when the author examined the species in 1998.

This is a gynodioecious tree up to 18 m tall inhabiting coastal forest, where it is usually a minor (rarely dominant) component of forest on rocky headlands and talus slopes, windswept ridge-lines, forested islands, and islets (de Lange 2023). Usually associated with Pohutukawa (Metrosideros excelsa), Puriri (Vitex lucens), Karaka (Corynocarpus laevigatus), Whau (Entelea arborescens), Kowhai (Sophora chathamica), Tawaroa (the northern wide-leaved form of Beilschmiedia tawa) and on offshore islands such as Manawatawhi / Three Kings, Poor Knights, Mokohinau Islands with Coastal Maire (Nestegis apetala), Ewekuri (Streblus banksii), Houpara (Pseudopanax lessonii), and Hoheria spp. (de Lange 2023). The fruits are fleshy and bird-dispersed.

Planchonella costata, though probably always confined to the northern portion of Te Ika a Maui / North Island, would have experienced a major range contraction following human settlement of that island. Lowland coastal forest, particularly that around harbours would have been rapidly cleared, and with it prime habitat for Planchonella. Planchonella is also highly palatable, seedlings, saplings and adult trees are sought out by livestock, feral goats (Capra hircus) deer (Cervidae), feral pigs (Sus scrofa), possums (Trichosurus vulpecula) and rats (three species). Rats consume seeds, so on those offshore islands with rats present, Planchonella is only found as adults that predate rodent arrival. Fortunately, adult trees are resilient, and provided there are male, hermaphrodite, and female trees present, populations will recover rapidly once browse pressure is managed. An additional threat to these island refugia is fire (human induced or otherwise) especially as some of the islands occupied by this species are remote.

Nationally the species was assessed as ‘At Risk / Relict’ by de Lange et al. (2018), qualified ‘PD’ [Partial Decline], ‘TO’ [Secure Overseas]. The qualification of ‘PD’ reflecting the gradual loss of specimens from sites where the threats cannot be managed. These losses are of course balanced by the increasing number of predator free locations with this species.

This species is occasionally seen in cultivation and sometimes sold by specialist native plant nurseries. Planchonella costata has been used for street and park plantings in some locations, such as Tamaki Makaurau / Auckland City.

The majority of the remaining Planchonella costata populations are now found on offshore islands historically free or recently made free from the majority of the browsing animals responsible for its extirpation or recruitment failure on Te Ika a Maui / North Island, Aotearoa / New Zealand. On those islands free of browsing animals provided there are male and female Planchonella, recovery of this species is rapid. Therefore, to secure this species requires excellent biosecurity to detect pest incursions and undertake a rapid response to these. An additional threat to these island refugia is fire (human induced or otherwise) especially as some of the islands occupied by this species are remote, so a fire would be difficult to detect. Fortunately, biosecurity and plans for the management of fires and pest incursions have been prepared for the majority of the islands groups supporting Planchonella, by the New Zealand Department of Conservation in partnership with iwi, not so much for this species but rather because the islands it inhabits support a range threatened biota sensitive to the same threats. 

Planchonella costata has been assessed as a ‘Relict’ species by de Lange et al. (2018) in recognition that most of the decline in the species in Aotearoa / New Zealand happened historically, and that with the exception of some parts of this species range, the remaining populations are either stable or increasing in size. The threats facing this species are well known, they can be managed for, and provided they are there is no reason to furnish this species with a higher threat assessment.