|Agroforestry in the Pacific Islands: Systems for Sustainability (UNU, 1993, 297 pages)|
Pacific Islanders, like people everywhere, "prospered by disturbing the natural order," as Carl Sauer (1952, 3-4) put it. The pioneering Pacific mariners found islands almost entirely covered by a mosaic of natural forest types. As the islands were occupied, the newly arrived settlers cleared forest for gardens and established orchards or agroforests that provided many valuable foods and materials. People also opened forest land to provide materials and space for houses. The ubiquitous use of fire, often for hunting, was a major tool in the change from forest to more open landscapes. These activities modified the natural landscape, creating a human habitat that was more congenial to occupation and much more productive of food than were the closed native forests. But as Sauer went on to say, human beings often overreach themselves, and the new order they introduce may contain the seeds of disaster. Or, as Oedekoven (1962, 55) suggested with regard to forests, humankind may ultimately cut off the branch it is sitting on.
In the Pacific before European contact, human activities caused many kinds of degradation. Deforestation has been prevalent in Pacific history; subsequent repeated burning has been responsible for the evolution of fire-climax forests, grassland savannas, and degraded fern and scrub lands (Clarke 1965; Farrell 1972; Manner 1981; Thaman and Clarke 1983). Such a process has undoubtedly been the main cause of the extensive anthropogenic grasslands of highland New Guinea; the xerophytic niaouli (Melaleuca leucadendra) savanna lands of New Caledonia; the highly degraded "sunburnt lands," or talasiga, found throughout Fiji; and the rapidly expanding saafa (Panicum maximum) grasslands of Tongatapu in Tonga.
Deforestation has led to severe erosion in Wallis and Futuna, the Cook Islands, French Polynesia, and Hawaii, where most of the indigenous forest has been removed, leaving degraded fern lands and grasslands no longer suitable for agriculture (Kirch 1982, 4). Flenley and King (1984) go as far as to suggest that deforestation was responsible for the collapse of the pre-European megalithic culture on Easter Island, a view supported by McCoy (1976, in Kirch 1982, 4), who argues that the "radical reduction of forest, shrub, and grassland communities, following over-exploitation and misuse by man," was responsible for a change from open-field cultivation to protected stone garden enclosures (manavai). Similarly, drastic deforestation of the central plateau on the Hawaiian island of Kahoolawe because of shifting cultivation and increasing population pressure between A.D. 1375 and 1600 reportedly led to a "dramatic population crash" and the total abandonment of the interior of the island by 1700 (Hammon 1980; Kirch 1982, 4).
It is clear that the Pacific Islands' early inhabitants did not avidly practice a conservation ethic that preserved their habitat as an unchanging paradise until Europeans brought major disturbances and degradation; instead, the early settlers caused many extinctions (notably of birds), reduced forest cover, initiated massive soil erosion, and created or extended degraded grasslands. In short, they did what all peoples, especially pioneers, do in their efforts to make a living: they actively manipulated, modified, and at times degraded the ecosystems in which they lived (Clarke 1991; Kirch 1984, 123-151).
But in their transformation of natural landscapes into cultural landscapes, the early inhabitants of the Pacific also developed - partly as an adjustment to the degradation they had caused - sustained-yield systems of agriculture, agroforestry, hunting, gathering, and fishing that still operate productively today but that are in danger of disappearing in the face of changing technological, social, demographic, and economic conditions.
The natural forests of the Pacific Islands fall into the general categories of lowland tropical rain forest, montane forest, swamp forest, mangrove forest, or coastal-strand communities. Locally, many Pacific forests are unique; their high endemism and fragility have attracted the attention of scientists, beginning with the first comprehensive biological studies on Cook's voyages during the eighteenth century and Darwin's observations on his voyage on H.M.S. Beagle in the 1830s. The forests' vulnerability to human-induced change has been stressed by Darwin (1895), Fosberg (1965), Mangenot (1965), Carlquist (1965, 1980), Mueller-Dombois (1975), Dorst (1972), and Dasmann et al. (1973). All categories of remaining natural forest are increasingly endangered as part of the worldwide process of deforestation resulting from urbanization, industrialization, commercial logging, agricultural development projects, and increasing population. As mentioned above, Dahl (1980) provides descriptions and conservation status for all terrestrial ecosystems in the South Pacific as well as lists of rare, endemic, or endangered species. Dahl also provides details for each island group or biogeographical province of the current and proposed conservation legislation, and of the existing, proposed, and recommended reserves.
All parts of the Pacific have ecologically and culturally important forest types or individual species that are in danger of depletion by human action. Some countries and territories have conservation legislation and forestry ordinances (Pulea 1984); Papua New Guinea and Hawaii have increasingly effective systems of forest reserves and conservation areas; and other places, such as New Caledonia, the Solomon Islands, Vanuatu, Norfolk Island, Fiji, French Polynesia, Kiribati, and some of the American territories, have had similar developments recently on a more limited scale. However, forest products continue to be shipped off for an inadequate return, while Japan, South Korea, China, and other countries continue to protect their forest resources and to implement major reforestation efforts (Richardson 1981). In New Caledonia, for example, where nearly all exploited timber species are endemic, most of the surprisingly rich native gymnosperm flora of 44 endemic species are now limited to a few restricted habitats. Most of the 13 species of Araucaria are restricted to active mining areas, and the local kauri species, Agathais lanceolata, has been exploited to near-extinction in southern New Caledonia (Dahl 1980, 37). Similarly, Agathis macrophylla, formerly abundant on Aneityum in Vanuatu, has been almost logged out. Selective unrestricted cutting, sometimes for shipping as saw logs, also threatens the Fijian form of this stately species, mature individuals of which may be centuries old.
Deforestation is proceeding rapidly in most of the Pacific. Forests, both primary and secondary, continue to be transformed into degraded savannas and fern-grasslands, mangroves into housing and industrial estates or other lifeless land-sea interfaces; and polycultural, treestudded, traditional agroforested gardens into monocultural plantations. Urban areas lose trees to make way for industrial, commercial, and residential areas or to fuel the cooking fires or to erect the squatter housing of low-income families. The trends are the same from the high continental islands of Melanesia to the smallest atoll islets of Polynesia and Micronesia.
Although deforestation, seen as the loss of forest as such, has received much more attention, "agrodeforestation" is probably of tantamount importance culturally and ecologically. Fewer trees are planted, and the great variety of useful tree species in gardens, villages, and towns is suffering depletion. The situation is particularly serious on smaller islands with little or no remaining native forest, where agricultural areas and home gardens serve as the few reserves where endangered plant varieties or cultivars can be protected. In Tonga, for example, during the height of the banana boom, so many trees were cut to provide shooks for banana boxes, and to extend banana plantings, that sawmillers had to move from Tongatapu to the nearby island of 'Eua. Thus, the search for meagre export earnings diminished valuable native species as well as food-bearing trees such as mango and citrus cultivars (Thaman 1976).
Most of the trees that now provide food, timber, firewood, and medicines, or that serve other cultural and ecological functions in Pacific agro-ecosystems, were deliberately planted or protected in the past. But few of them are being replaced or protected by the present generation. Opening a tin of imported peaches for a feast, going to the local dispensary or pharmacy for medicines, or purchasing imported plastic flowers, perfumes, and deodorants, have replaced the products that came from trees. Of particular concern is the ubiquitous senility of Pacific Island coconut palms, the only source of export income on many of the smaller, more isolated islands, as well as a very important source of food, drink, and materials. Despite limited replanting, the declining yield of palms, often planted before the turn of the century, augers poorly for the economic future of these areas. On the other hand, areal expansion of coconuts, as currently promoted, is commonly at the expense of other land use-soften arboreal. A singular case was that described by Spoehr (1949) in the Marshall Islands, where the Japanese ordered the removal of breadfruit trees so that copra production could expand, thus lessening arboreal diversity and eliminating a tree that produced food, medicine, canoe hulls, and caulking. Similarly, in Kiribati, only recently has the Government acknowledged that some 20 years of institutionally-sponsored coconut replanting and rehabilitation have led to the gradual elimination of a wide range of ecologically and culturally important tree species, all traditionally components of the Kiribati agricultural system (Thaman 1989b).
Although some countries have increasingly effective systems of forestry reserves, conservation areas, or national parks, few, if any, have legislation or programmes prohibiting the cutting - or promoting the replanting - of endangered tree species as part of agricultural development. Thus, agrodeforestation continues with little or no official recognition and, therefore, few attempts to reverse the trend (Thaman 1989a).
Aside from the loss of materials and ecological services, which will be discussed in detail in the next chapter, agrodeforestation also means a cultural loss because a significant part of Pacific intellectual heritage is an intimate feeling for the social and spiritual meaning of trees, together with an immense knowledge of their habits and products. As the trees disappear, traditional knowledge is eroded, and landscapes lose the depth of meaning imbued by protected or planted trees. Although commonly useful trees are in no immediate danger of becoming extinct because of agrodeforestation, biodiversity is diminished because many agroforest species contain a great number of varieties or cultivars, each with its own characteristics. If these varieties, which are the result of generations of careful selection, are lost, the local food-production system will be degraded. For instance, in a recent study, Fownes and Raynor (in press) report that as many as 130 cultivars of breadfruit (Artocarpus altilis) are recognized by farmers on the volcanic Micronesian island of Pohnpei, where breadfruit collected from a traditional agroforestry system is a major staple food for people during several months of the year and is also a major food source for pigs, which roam the understorey consuming fallen fruit during the peak season. Fownes and Raynor investigated five cultivars (a small fraction of the recognized number) and found that they varied in seasonality, growth form, and yield. Complementary seasonality among the cultivars led to an extended fruiting season in the aggregate.
The Pacific remains fortunate because many such traditional agroforestry strategies still exist, if only in relict form. None the less, increasing agrodeforestation and the gradual disappearance of time-tested agroforestry systems and their component species and varieties in the face of the expansion of monocultures and commercial livestock, population growth, increasing demands for fuel, continued urbanization, and the "commercial imperative" (fudge 1977) are the dominant trends, which will only be reversed by deliberate planning and action. In an attempt to help facilitate such planning and action, this study emphasizes throughout the roles that particular traditional and existing agroforestry systems and their component trees play, and could continue to play, in the provision of useful materials, the enhancement of the environment, the maintenance of the stability of agroecosystems, and the reversal of deforestation and agrodeforestation.