Introduced Trees on Atiu 1850-2050

Paiere Mokoroa
Feb 2009

This paper is on the impact of foreign trees introduced and planted in Atiu.  The main sources are interviews and personal observations.  The Cook Islands has experienced several crucial changes for ‘good’ over many decades.  These include many trial projects on land use, mainly for agriculture and environmental purposes.  Not many have succeeded in the long term.  How can we do better in future?

Background
The land area of Atiu is about 26 square kilometers. Smaller than Rarotonga or Mangaia.  In chants and karakia Atiu is described as ‘potipoti ‘enua’ meaning a very small island.

The landscape today is green and heavily covered with tall pine trees and albizzia with their foliage displaying the beauty of today.  So it is labelled sometimes as ‘The Green Island’.  It is no longer called ‘Enua Kura’, meaning ‘Red Island or ‘Red Clay Hilltop.’

The population of about 600 according to a recent survey, consists mainly of oldies and children.  The 17-28 year age group are attending school or earning money in Rarotonga.  A lot more have migrated to New Zealand and Australia.

A Glance Into the Past
Let us trace the main trends from the time before contact with the Western world.  Until then, the trees on Atiu were those that had arrived with birds or floating seeds before human times, and those brought by Polynesian settlers including breadfruit, bananas, chestnut and coconut.

The island was then totally self-sufficient.  The people lived in hamlets beside the taro swamps, which were the main source of water and subsistence, and close to the lagoon for marine foods.  Then the mission encouraged to people to move to one central settlement (no’otu) on the central plateau.

One of the early missionaries, William Wyatt Gill, wrote in 1856 that “As we neared the village, a view of exciting beauty burst upon us: the ocean, a dense forest, a lake, numerous valleys well planted with breadfruit and chestnut trees.” Missionaries, travelling Atiuans and traders brought other trees in the 1800s, including pawpaws, avocados, oranges, coffee, kapok and other plants.

Today that past is lost in the “Greens of today”- the imported trees.  The main ones were imported in the 1950s in the hope of facilitating economic development.

Fifty years ago, if one stood on the outskirts of the inland settlement (no’otu) one could see the blue ocean only two kilometres from the hillsides. Takutea and Miti’aro could be seen on the horizon northeast of Atiu.  The makatea treetops almost level with the lowland coconut trees provided colourful flowers of the ngatae (coral tree – Erythrina variegata) and tuti (candlenut – Aleurites moluccana) flowers during spring time.  In the valleys, ripe oranges and chestnuts glistened in yellow shade all ready for harvest.  Whatever caught your eyes from the sea to the hills was visible because there were no tall trees to block out the scenery. The hills were covered with native ‘tuanue’ ferns and a few casuarina trees.

Foreign Trees Introduced
Foreign trees have been introduced to the Cook Islands since the 1800’s.  Most were fruit trees- oranges, mangoes, pawpaw, avocado, coffee etc some of which were exported to Tahiti in the 1800’s and New Zealand in the 1900’s.

During 1950 to 1970 more foreign trees were brought in for specific purposes e,g the pistachio (Pistacia sp.) was grown as wind break along boundaries of plots for  the citrus trees, especially oranges.  When orange production ceased in 1978 pistachio trees spread over the hills and down the lowlands, overgrowing the native plants. Pistachio is hard to kill because new sprouts grow from the cut trunk, roots and seeds.

Albizzia falcata were grown to provide timber for boxes to pack oranges and pineapples to ship to Rarotonga and New Zealand.  The trees were not ready when pineapple and orange production ceased due to high costs of fertilizer and very erratic shipping.  Moreover, oranges should be replanted every 20 years or so, and that was not done as the income and unreliability of shipping demotivated the farmers.

As the albizzia multiplied and grew taller above the coconut palms, the coconut withered, reproduction ceased, the leaves fell off leaving trunk topless.  Albizzia falcata is the fastest growing tree in the world, and one in Malaysia grew over 35 feet in 13months, or 1.1 inches per day (United Nations Environment Programme, 2009).

Pines (paina – Pinus radiata) were introduced from New Zealand in the 1970’s to stop soil erosion on hillsides and improve the fertility of the red soil on the fern-lands which were then being cultivated for planting pineapples.  The trees do control soil erosion and slowed the water runoff and washing of red soil into the taro swamps and in some cases into the lagoon where red soil, which is rich in iron, destroys some corals.

The scheme was funded by the New Zealand Government and a Forestry Division was established in the Ministry of Agriculture to manage the scheme. Later the scheme was handed to the Cook Islands Government. However, the growth of the pine is fantastic.  The trees are straight and reach 15 metres.  In some areas the fallen dried leaves have buried the tuanue ferns (Dicranopteris linearis) – perhaps killed them.  The tree trunks are suitable for timber but it needs to be treated.

The eucalyptus is the world’s tallest tree (United Nations Environment Programme 2009). It is a hard, strong wood – stronger than the ironwood (toa – Casuarina equisetifolia).  Small eucalyptus trees are best for fence posts on dry land and swamps.  But it continues to grow if the bark is not removed at the ground end.

Eucalyptus has its disadvantages.  It draws a lot more water from the soil than the au (hibiscus) tree.  It causes dryness on fern lands and reduces the water supply into the swamplands.  The tree is also hard to kill as new shoots grow from the stem.
Acacia mangium (black wattle) was also introduced experimentally in the 1950s.  It is a fast-growing leguminous tree that gives out nitrogen through its roots, and its timber makes excellent furniture.

There has been no significant export from Atiu since 1978 when orange and pineapple production ceased.  Although taro is fetching good income, the supply is not enough for the market demand in Rarotonga or New Zealand.

Thoughts For Tomorrow
Foreign trees introduced in the early 1950-70’s were intended to be useful for the purposes for which they were brought. Yet some of them became a threat to the people in the next twenty years.  The Local Government Act prohibits lighting of fires on fern-land.  The Environment Act and Regulation on conservation is on the “go”.  No one can escape these acts and regulations whenever they are breached.  During the 1950’s landowners on Atiu were fined because they were unable to eradicate onion grass, lantana and rakau Papua from their lands.  Lantana (Lantana glauca) were brought for its colourful flowers.  It did not remain as a domestic plant but spread widely as a pest. Atiuans were fined when these plants from other countries spread over their land.

The pine trees, albizzia, acacia, eucalyptus and others survive beautifully everywhere. They were planted on hillsides, away from the swamplands and the plateau, but acacia and albizzia have spread over the flat lands. Pines have not spread much. The camrina is spreading into the swamplands. A mass of trees can be seen at Uturei and Taparere or in Mapumai. They are creeping closer and closer to my property year by year. They surround the homesteads on the outskirts of the settlement, tourist accommodation, the school etc. When fires break out and spread they would not only be on the ground but also up in the tree-tops. Everything is in danger of burning.
In the 1980’s a fire started on the north-west side of Tengatangi.  In three hours or so it had reached Uturei land.  Luckily it was put out by volunteers, but it demonstrates the continuing fire hazard.

Solutions For The Future
Any project costs money to manage.  However, the control system can be on a “money income” basis.  As they are almost impossible to eradicate totally, the trees can be farmed.  For example pines and albizzia can be milled for building timber.  Taka’iti Sawmill, the only sawmill on the island, has milled albizzia.  The Island Council has sought to acquire a mill under foreign aid, but Island Councils do not have a good record at running commercial projects.

A quick search of Google shows that many companies in China, Indonesia, Japan and elsewhere buy and process albizzia, acacia and other timbers grown on Atiu for house-building, furniture and other uses, but the costs of getting small quantities from Atiu to distant markets are likely to be prohibitive.  The Cook Islands market has most potential.

Pine trees can also be cut for domestic use or for sale to other islands. If permission is given to cut pine trees, then old ones can be cut and new ones planted. Acacia trees can be chipped for compost for sale in Rarotonga.

In 1988 Miti’aro had a machine for processing compost using coconut and puka leaves.  If Atiu could buy a processing machine to turn acacia and pistachio into compost there could be an income, though the economics of it has not yet been assessed.  An alternative is to look back into the project promoted by the then Democratic government of Dr Tom Davis to use acacia for energy production for electricity.  Maybe reviving that failed project could be useful to offset the present high cost of production of electricity from imported fossil fuel like diesel.

Future policy
Global changes have become a great issue for the world in the future, including the Cook Islands – especially in the northern atolls of the Northern Cook Islands.  The Southern Cook Islands may suffer drought. It is time to ‘step up’ reform planning both in the community and the government as well ‘Awareness Curriculum’ in the schools, adult education and so on.

References
Gill, William Wyatt  1856  Jottings from the Pacific, reprinted in Atiu Through European Eyes, p.41, USP, Suva 1982.
United Nations Environment Programme 2009. “ Interesting Tree Facts,”  onwww.unep.org/Document445+article48528d, New York.
Wilder, Gerritt, 1941. Flora of Rarotonga, Bishop Museum publication no 86, Honolulu.

Interviews
Dr Roger Malcolm, Atiu
Ma’ara Tairi, Agriculture Officer, Atiu.
William Hosking, retired Secretary for Agriculture, Rarotonga
Othaniel Tangianau, OMIA, former officer in charge of forestry in Ministry of Agriculture, Rarotonga.

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