Nestegis

The four native tree species from the genus, Nestegis, were previously referred to as the New Zealand olives. Although they are no longer considered to be olives (that is, members of the genus, Olea), their old name was well founded – as Nestegis is still placed within the olive family (Oleaceae). They are more readily known to New Zealanders by their Māori name, maire¹.

A notable characteristic of maire is their extremely hard wood; particularly that of black maire (Nestegis cunninghamii, pictured below). Within our native flora, only southern rātā has harder timber than black maire; a fact that is not lost on carpenters whose tools have been blunted by the maire’s dense timber. Due to the hardness and durability of its timber, maire was traditionally utilised for a range of specialised tools or objects by both modern New Zealanders and pre-European Māori; such as ko (digging sticks) or canoe paddles, or even as a substitute for metal bearings in machinery and implements².

Another, less fortuitous, quality of maire is their suitability as firewood, a use that has caused large quantities of black maire to literally go up in smoke over the last century (and which, thankfully, is no longer common practice). One of the most original functions to have ever been proposed for New Zealand’s ‘olives’ was offered by William Colenso in 1868³, when he suggested that “the European olive might be advantageously grafted upon the several indigenous olives of the island”, to assist in the establishment of an olive-growing industry in New Zealand. Although I have come across one species of Nestegis (N. montana) grafted on to another (N. cunninghamii) by an ornamental nursery, I have never heard of an instance in which Colenso’s suggestion has been tried out.

It has been good to see over recent years that some Auckland City Council arborists have expressed interest in their use as street trees (including planting the elegant species pictured above at Waipoua Forest, Nestegis montana), and for other amenity uses. Although capable of growing in excess of 10m, our native species of Nestegis normally attain smaller dimensions and have a relatively compact growth form – rendering them worthy of greater attention as specimen trees, especially in urban areas and parks.

Of the many native trees that should be better represented within cultivation, this small tree is one of the most glaring omissions from our gardens. It is native to the northern coastline of the North Island (in addition to growing naturally on Norfolk Island), and is therefore most suited to growing in warmer areas of New Zealand.

The most outstanding characteristic of N. apetala is its growth form. Its spreading branches often grow in a ‘winding’, tortuous manner, similar to the way in which pohutukawa frequently develop. This gives them an expressive appearance, of the kind that bonsai enthusiasts regularly attempt to imbue into their subjects. Furthermore, what sets coastal maire truly apart is that they assume this form on a relatively small scale (N. apetala can grow up to 6m) – one which is more suited to many urban properties than very large trees like pohutukawa.

Its other great attraction is the foliage, which has a brightness and depth of hue that is very valuable in garden trees. Nestegis apetala is often found within rocky coastal habitats; and, accordingly, is well adapted to the difficult conditions associated with much of the human landscape.

As with many coastal natives, it responds well to considerable amounts of fertiliser; due to a natural history of millions of years in which countless seabirds would have deposited guano upon our coastal forests⁴. Although not common on the mainland, coastal maire survives in good numbers on northern offshore islands, especially where pest animals cannot affect their populations.

In line with other members of its genus, its timber is very hard and durable; as evidenced by its common name upon Norfolk Island – ironwood. In the nineteenth century, it was used in the copper mine at Great Barrier Island for such articles as mine props and machine bearings². N. apetala was initially discovered to science on Norfolk Island, and was subsequently found on northern offshore islands in New Zealand in the latter half of the nineteenth century.

There have been occasions when I have joked to friends that a potential title for a book focussed on New Zealand’s full diversity of plants and ecologies might be called “You’re looking the wrong way !”. This stems from an incident at Tauroa Point (at Ahipara) when my camera (and as a result, the rest of me) was pointed inland towards a swamp in which the critically-endangered Hibiscus diversifolius endures. At precisely this point, a ute drove past on the beach, from which a bogan yelled out those wise words. After all, what possible reason could any right-thinking person have for being more interested in a dune wetland than the vast expanse of ocean at his back ?

Alas, this appears to be an affliction that often surfaces in my case; as in the example of the image below, left, in which my back was firmly turned on Tane Māhuta (New Zealand’s most famous tree), due to the presence of a particularly nice specimen of oro-oro (Nestegis montana) behind the observation deck from which that majestic kauri is viewed by hundreds of thousands of tourists every year. Tane Māhuta is obviously the main event in Waipoua, but the entire community of plants surrounding it merits observation – especially due to the fact that we can’t all share space with a thousand-year old kauri in our everyday environments.

Much of oro-oro’s appeal rests in its graceful, narrow foliage, which bears comparison with various species of willow or bamboo. Such a resemblance is notable for the connotations that we attach to certain plants due to inherited cultural associations; one prominent example being the role that willow occupies within many European and Asian societies (or even our own rural landscapes). Nestegis montana therefore represents a native proxy for introducing the character of willow or bamboo into plantings without the considerable ecological harm that can accompany the use of some species of those culturally significant plants.

Despite its specific epithet, Nestegis montana is not strictly associated with montane areas, as evidenced by the secondary dune forests at Pouto Peninsula, where it is a very common component of the ethereal woodlands that endure within dune hollows and nearby forested slopes. In parts of this impressive landscape of gigantic dunes, oro-oro forms unusual pure stands, as demonstrated by the pulsing green canopy of N. montana in the centre of the image below. The perspective from which this photograph was taken gives some sense of the terrain, wherein the woodland is set within the deep basin of a dune hollow, lending the sense of a hidden forest (that only becomes apparent as one approaches it).

Like other members of its genus, oro-oro is a tree that should be planted to a much greater extent, due to its extremely useful growth habit (it grows readily on a clear stem, and can be maintained at a wide variety of scales), the highly attractive texture offered by its foliage, and the vibrant hue of its new growth (which contrasts against the darker green of the previous seasons’ leaves). As with our other Nestegis species, it has been trialled within innovative street tree plantings by Auckland Council arborists, in which it has been highly successful.

Oro-oro is mostly confined to the North Island, with very small, relictual populations in Nelson and Marlborough. In Nelson, the species was down to just a handful of specimens when some innovative work by Martin Conway (former owner of Titoki Nursery) and Lawrie Metcalf set up the opportunity for seed to be gathered from one of the widely-scattered trees⁵. The progeny from their efforts are now repopulating environmental plantings and gardens in the greater Nelson area – including one of our projects near Motueka. Nestegis montana was described (to Western Science) by Joseph Dalton Hooker in 1853 on the basis of collections that William Colenso (with whom J. D. Hooker shared a lifelong correspondence) made.