|Agroforestry in the Pacific Islands: Systems for Sustainability (UNU, 1993, 297 pages)|
|3 Agroforestry in Melanesia: Case-studies from Papua New Guinea and the Solomon Islands|
In 1972, population densities on the Weather Coast of southern Guadalcanal, the Solomon Islands, ranged from 1.5 to 26.4 persons per sq km (Chapman and Pirie 1974). Pressure on land was low in the vicinity of Kologhona village, some 10 km inland from Babanakira in the upper Tina River Basin of the Wanderer Bay area. The village, which had a population of approximately 60 in early 1975, had access to extensive areas of alluvial and colluvial soils, steeply sloping garden land covered with secondary forest, and considerable areas of slightly disturbed primary forest along the crests of the ridges and on the steeper slopes.
The two most common subtypes of agroforestry practiced in Kologhona are ago-puka and ago-male. The ago-paka method is practiced in old forest at some distance from the village. All but the biggest trees are felled, after which the debris is piled around the bases of bigger trees and burned. No attempt is made to clear all stumps or level the ground before planting commences. Traditionally, planting was almost exclusively women's work, using digging sticks and hoes; men are increasingly doing more of this work. Yams and Colocasia taro are the most common crops planted in these gardens, although other ground and tree crops are also planted. Fallen trees are allowed to lie in the garden, often placed along contours to retard erosion and to provide for trellising yams and other climbing plants.
In the more heavily cropped alluvial and colluvial soils and gardens closer to the village, the ago-male method is more common. Its practice means the extension of existing gardens into surrounding secondary vegetation by clearing, moving the debris to the side, and planting without burning (Rainbow and Teteha 1983). Sweet potato is the major crop in these gardens, intercropped with yams, taro (Colocasia and Xanthosoma), banana cultivars, and a diversity of other crops, including sugar cane, Saccharum edule, Hibiscus manihot, pumpkin, pineapple, maize, chill) peppers, and tobacco.
Trees with edible fruits and nuts are commonly protected when secondary vegetation is cleared, or they are planted amongst crops. Trees so treated include breadfruit, coconut, betel-nut, papaya, Citrus spp., Canarium spp., Inocarpus fagifer, Barringtonia edulis, Syzygium malaccense, and Ficus copiosa. Other useful tree or tree-like species maintained in gardens include Pandanus tectorius, kapok (Ceiba pentandra), and sago palm (Metroxylon salomonense) and
Heliconia indica, both of which are found mostly in poorly drained areas close to the river. In fallow areas, the commonest pioneer species are Kleinhovia hospita, A lstonia spp., Ficus spp., and Macaranga aleuritoides. Wild foods - including wild yams (Dioscorea spp.), a range of ferns, and other wild greens - and animal foods are either preserved through selective weeding or occur in fallow and secondary vegetation.
Despite increasing population pressure, the preservation of trees as part of an integral agroforestry system has continued. However, increasing pressure by the government to expand monocultures of copra or cocoa and the smallholder production of beef cattle, with no emphasis on the maintenance of arboreal diversity, is accelerating agrodeforestation on the Weather Coast and will play a major role in the decline of arboreal diversity and self-sufficiency and the loss of knowledge of traditional agroforestry systems among young agroentrepreneurs.