Based on a paper presented at the South Pacific Indigenous Nuts Workshop, Port Vila, Vanuatu, November 1994 by Dr. Michael Bourke, Department of Human Geography, Research School of Pacific and Asian Studies, Australian National University, Canberra, ACT, 2600.
There are over forty indigenous plant species with an edible kernel in Papua New Guinea (PNG) but only eleven are classed as being important in village agriculture.
Of these, six are seen as having potential for commercial development. These are cut nut or pao (Barringtonia procera), galip (Canarium indicum), karuka (Pandanus julianetti), okari (Terminalia kaernbacchii), Polynesian chestnut or aila (Inocarpus fagifer), and sea almond, talis or Java almond, (Terminalia catappa). All six species, particularly galip, karuka and okari, are marketed locally and are sometimes sent to more distant markets within PNG.
The main criterion for selecting these species as having potential for commercial development was their acceptability by people from outside the area there they are traditionally grown. Commercial ventures are currently being established for roast galip nut in West New Britain and for fresh okari nuts from the Managalas Plateau in Northern Province.
People live and practise agriculture over a wide range of environments in PNG. These cover, an altitude range from sea level to 2800 m; a rainfall range from 1000 to 8000 mm/year; climates with no dry months to those with an average of seven dry months; and land forms which include raised coral reefs, coastal plains, mountains and hills, colluvial fans and highland valleys.
Nut-bearing species and other tree crops are grown in all inhabited environments, but there are three in which they are particularly important for villagers' food supply.
The first of these is the high altitude zone (1800 to 2400 m) and the very high altitude zone (2400 to 3000 m) where karuka and wild karuka nuts are very important. Villagers living in these zones commonly trade karuka nuts with those living in the main highland valleys between 1400 and 1800 m.
The second important environment is the highland fringe (600 to 1200 m) on the New Guinea mainland. Here, the staple foods include combinations of sago, bananas and root crops. These are supplemented by marita pandanus fruit (Pandanus conoideus), breadfruit seed, tulip (Gnetum gnemon) leaves and seed, and sometimes castanopsis nuts (Castanopsis acuminatissima) and sis nuts (Pangium edule).
The third environment in which tree crops, including nut-bearing species, are particularly important is that on small islands. These include those off the north coasts of New Guinea and New Britain, those east of New Ireland, the Mussau Islands and the islands of Milne Bay Province.
While still and important component of the diet, there has been a steady decline in the significance of fruit and nut tree crops with an increase in arable agriculture in these islands. The major change in agricultural production has been the incorporation of sweet potato and cassava into agricultural systems.
Cut nut (Barringtonia procera)
This species has a very limited distribution within PNG. It is commonly grown and eaten on Bougainville Island, New Ireland, the Gazelle Peninsular of New Britain and on Karkar Island. It has been suggested that this limited distribution is the result of it being a comparatively recent introduction that originated from the Solomon Islands.
Cut nut is grown from sea level to 500 m altitude, near the coast and in inland locations. The rainfall range is 2000 to over 4000 mm/year. Production appears to be intermittent throughout the year and non-seasonal. In the Bismarck Archipelago cut nut is eaten by outsiders, including expatriates. This acceptance suggests that it has good prospects for commercial development.
Galip (Canarium indicum)
Galip is widely distributed in lowland areas on the northern side of New Guinea and in all island groups. Galip grows near villages, in woody regrowth after cultivation and in mature forest. Trees are usually dispersed and not grown in groves. Self-sown seedlings are protected and trees are planted, often being selected for desirable characteristics.
Galip grows from sea level to 700 m altitude and in locations with a wide range in rainfall from 2000 to 6000 mm/year. It occurs on both well-drained and poorly-drained sites in forest locations but is uncommon in grasslands.
Production is typically seasonal and generally lasts for about three months. The production pattern is independent of the rainfall pattern but the commencement of production varies with latitude, which suggests that it is determined largely by daylength. Anecdotal evidence suggests that there is considerably genetic variation with the species in PNG. Galip is popular among outsiders, including expatriates, and the the prospects for its commercial development are considered to be excellent.
Karuka (Pandanus julianettii)
Karuka is very widely planted in a narrow altitudinal band in the highlands in the central cordillera of New Guinea and on the Huon Peninsula. Kuruka nuts are an important part of highlanders' diet during the producing period, being one of the few high protein plant foods in the region. During the harvest, entire households and their domestic pigs often migrate from the highland valleys up to the high altitude locations.
Karuka grows between 1800 and 2600 m and in locations with a mean annual rainfall from 2000 to 5000 mm. It grows well on poorly-drained sites but can also be grown on better drained sites. It is grown as individual trees and in large groves in primary forest and in woody regrowth and cane grass. It does poorly in open sites and short grasslands.
Production is irregular in the western part of the highlands where changes in the rainfall pattern are slight or absent. In the eastern part of the region where the rainfall is seasonally distributed, production approximates to an annual seasonal pattern, but there is still large year to year variation in the size of the harvest. The biggest harvests have been observed to follow major droughts.
Karaku nuts are very popular amongst the highlanders and, to a lesser extent, amongst outsiders. Unlike galip, most of the available nuts are harvested and consumed. This suggests that commercialism could have an adverse effect on the quality of the diets of householders who normally harvest and consume the fruit.
With this reservation, karuka is seen as having considerable potential as a commercial nut within PNG in the 1800 to 2600 m altitudinal zone, and possibly in other areas that experience seasonal temperature differences.
Okari Terminalia kaernbachii)
Okari has a limited distribution within PNG. It is very common in inland locations on the central cordillera from the Irian Jaya border in the west to Mt. Dayman in the east. It also occurs in a few inland locations on the northern side of the main ranges and in West New Britain between and Aria River and Cap Gloucester.
Okari does poorly near the ocean and grows best in inland lowland and at intermediate altitudes up to J 100 m. This may be due either to a negative effect of salt or a response to the greater diurnal temperature variation that is found away from the coast. It appears to tolerate poor drainage and grows at locations with a wide range of rainfalls from 2000 to 7000 mm. The production period is quite often regular from year to year and is independent of rainfall. There is a close relationship between the start of the production period and latitude, which suggests that it is largely determined by day length. It is reported that trees at Keravat in New Britain grown from seed from the Northern Province have shown a large variation in nut and kernel characteristics.
Okari nuts are popular in Port Moresby and in other urban centres in the producing region. Given the very extensive stands that occur in many locations in New Guinea, there would appear to be good prospects for commercial development from existing trees.
Polynesian chestnut (Inocarpus fagifer)
Polynesian chestnut is widely distributed in the lowlands on the northern side of New Guinea and on all island groups. It is most important in the Bismarck Archipelago and on the islands and mainland of Milne Bay Province.
This tree grows from sea level to 400 m in altitude in coastal and near coastal locations, usually near villages or in wood regrowth. The nut is not popular outside the islands where it is commonly grown and the prospects for commercial development appear only moderate.
Sea almond (Terminalia catappa)
Sea almond is widespread in most coastal regions of the New Guinea mainland and islands. It is usually confined to beach areas and village sites near the beach but occasionally grows to 400 m altitude. Most trees are self-sown.
In most of PNG, the nuts are eaten only by children or not at all. However, it is most important in the islands of the Milne Bay Province where it is eaten by both adults and children. The production period occurs between November and March with December to February the most commonly reported period.
Prospects for commercial development appear to be reasonably good, particularly if cultivars with soft shells and large kernels, such as are found on the island of Iwa in the Marshall Bennett Group, are used.
DATE: July 1996
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