Norfolk Island pine: Charting the history of rare conifer

THIS 8x5 km extinct volcanic land mass (with two smaller neighbouring islets) makes up the Australian external territory of Norfolk Island, just over 1,400 km adrift from the nearest mainland. It lies roughly midway between New Zealand to the south and New Caledonia to the north as the albatross glides.

The first Europeans known to have sighted Norfolk Island were Captain James Cook and his crew in 1774 on his second of three voyages to the Southern Pacific on the good ship HMS Resolution. 

In his log, the explorer noted the presence of extensive forests of tall, straight trees there that, to his nautical mind, appeared to be shipshape and Bristol fashion as masts and yard arms for sea-going sailing vessels. 

The first settlers were East Polynesians, but they may already have departed when Britain took the island on board as part of its 1778 “settlement” of Australia. 

The remote island served as a penal colony from then until 1855, except for an 11-year hiatus from 1814 to 1825, when it lay abandoned. 

The tree is perhaps best known for appearing on the Commonwealth Nation’s distinctive flag. (Image: Getty)

Permanent public residency began in 1856 when descendants of the Bounty mutineers were relocated from Pitcairn Island. 

In 1914, the UK handed Norfolk Island over to Australia to administer as an external territory.

At home with the tree

Found in the wild, native only to this remote piece of land is the so-called Norfolk Island pine Araucaria heterophylla (synonym A. excelsa). This endemic evergreen is an icon and is pictured on its flag. It is sometimes dubbed a Star pine, Polynesian pine, triangle tree or living Christmas tree, due to its symmetrical shape as a youngster. 

Yet it is not a true pine, which belong to the genus Pinus, but a member of the genus Araucaria in the family Araucariaceae. 

More distant family members, cast adrift when the supercontinent known as Gondwana began to split in the Jurassic era some 180 million years ago, include the monkey puzzle (A. araucana) and the Paraná pine or candelabria tree (A. angustifolia) in southern South America. It is related to the recently discovered Wollemi pine (Wollemia nobilis) in Australia. 

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Other Araucaria occur across the South Pacific, especially concentrated in New Caledonia (about 700 km due north as the albatross glides) where 13 closely-related and similar-looking indigenous species dwell. 

In a classic case of mistaken identity, many of the ‘Norfolk Island pines’ grown in Hawaii, and their descendants used as potted ornamentals on the US mainland, are actually the closely-related Cook Island pines (A. columnaris) since the two different species were confused when first introduced. 

In the wild the Norfolk Island pine is slow growing, but can reach a height of 50–65 m with straight vertical trunks and distinctive symmetrical branches, even in the face of incessant onshore winds that can contort most other species. 

Five branches stretch out almost horizontal or slightly oblique from the main stem, forming layers or floors; the plane of each level is a perfect pentagon. 

The young leaves are soft and awl-shaped, 1–1.5 cm in length, about 1 mm thick at the base on young trees, and incurved, 5–10 mm long and variably 2–4 mm broad on older specimens. The thickest, scale-like leaves are on the coning branches of the upper crown. 

The scientific tag heterophylla (“different leaves”) reflects this variation in the leaves between young and adult plants.

It is normally a dioecious tree (male and female flowers on different plants), although it can be monoecious.

The cones themselves are squat and round, 10–12 cm long and 12–14 cm across, and take some 18 months to mature when they then disintegrate and release the large, inch-long edible, nut-like seeds. 

Uses

Despite Captain Cook’s nautical aspirations, when the island was populated in 1788 by felons transported from the British Isles to serve life sentences, Norfolk Island pines did not prove resilient enough for ship construction and the idea was shelved.

Moving on a couple of centuries, in the late 1950s, a trial shipment of Norfolk pine logs was dispatched to plywood manufacturers in Sydney, in the hope of developing a timber export trade on the island. Although the Australian mills reported excellent results, any industry was deemed unsustainable by the Island Advisory Council, which opted to reserve timber production exclusively for local use.

The wood is good for woodturning, though, and is crafted extensively by artisans.

Yet like a number of other scarce plant species, the Norfolk Island pine has proven a success when cultivated as an ornamental far away from its homeland.   

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Norfolk Island pine can be found in homes across the world. (Image: Getty)

The distinctive look of this tree, with its widely-spaced branches and symmetrical, triangular outline, has made it a popular cultivated species, either as a single tree or just occasionally in avenues.

As the tree approaches maturity, the shape becomes less symmetrical and loses some of its charm, though. 

This eye-catching tree is widely planted as an ornamental feature for its exotic, pleasing and attractive appearance and fairly broad climatic adaptability, and now occurs throughout the world in regions with suitable Mediterranean and humid subtropical climes. It grows well outside in southern California, Florida, parts of Australia and around the Mediterranean Basin. 

When planted outside, the trees need adequate space, as they can grow and spread to an appreciable height of some 30 m. 

It grows well in deep wet sand and tolerates salt-laden winds, making it ideal for landscaping in coastal situations.

As a popular ornamental architectural plant it is frequently tended in pots in the house and sometimes pressed into service as a Christmas tree in North America.

Araucaria heterophylla is popular in gardens in milder parts of the USA but rarely survives outside in the more bracing UK climate, although a few specimens can be found in some gardens particularly in the South West and in Ireland. One example is the subtropical collection of Tresco Abbey Gardens on the Isles of Scilly, cosseted by the Gulf Stream. 

If you fancy one for your living room or conservatory as a fashion statement or a talking point to impress the visitors, various outlets in the UK offer this plant as a potted oddity in the price range of £30 to £70. 

Indoors, the plant needs a bright location with moderate humidity for good growth, yet away from scorching sunlight or heat sources, mimicking a Mediterranean environment.  

In the USA, large numbers of Norfolk Island pines are raised in Southern Florida in particular for the houseplant industry. The bulk of these are shipped to grocery stores, discount retailers and garden centres during November. 

Many are then sprayed with a light coating of green paint before going on display to boost their visual appeal and saleability. Of course, that adornment may weaken or even kill the plant if it cannot metabolise adequately, but then looks are everything in commerce just as long as the young plant lasts until the New Year.

Conservation and weediness

In the wild, the tree is slow growing but can reach heights of 50–65 metres. (Image: Getty)

The International Union for the Conservation of Nature and Natural Resources (IUCN) is the body that draws up a sliding scale of how likely each species is prone to disappear from the face of the Earth. The seven-step ladder extends from those of least concern (LC) to those already feared extinct (EX). 

Under that international system, the Norfolk Island pine is classed as “Vulnerable” – just one of approaching 7,000 plants in that category worldwide – i.e. “as being threatened with disappearing unless the circumstances that are menacing its survival and reproduction improve”. 

One might speculate that any terrestrial organism confined in the wild to just one small remote island could be in dire straits in its native home should a chance adverse event loom. 

So the NIP is classed as vulnerable as anything untold such as an exotic killer pest or disease or a wildfire might wipe out the wild stock across the entire island. Indeed, the stands of this tree there have contracted since Cook’s landing thanks to farming and overzealous logging.

Yet the vulnerable docket does embrace many other living beings that are in some potential danger in the wild but are reared commercially or propagated in captivity successfully as a safety net. A. heterophylla is one of them, as well as proving a money spinner. 

Back in its native habitat, the best surviving endemic stands on the island are now afforded protection in the 6.5 km2 Norfolk Island National Park, gazetted in the mid-1980s.

As a twist to this story, New Zealand has long been a second home to an array of invading, alien flora and fauna – and the first saplings of Araucaria heterophylla are turning up as weeds amongst forestry plantations of other introduced, commercial conifers.