|Agroforestry in the Pacific Islands: Systems for Sustainability (UNU, 1993, 297 pages)|
|10 Agroforestry in the Pacific Islands: Systems for sustainability|
It will be clear to any reader who has come this far that the authors of this book believe that the maintenance and further dissemination of agroforestry offer great benefits to Pacific Island peoples. We also recognize, however, that there can be costs, that there can be disadvantages, connected with agroforestry, at least as perceived by individuals or by some parts of the community. The views opposing agroforestry, as well as the views supporting it, need to be included in the discussion. The advantages and disadvantages of agroforestry have been subject to considerable analysis in the literature, for instance by Arnold (1984) with particular regard to economic constraints and incentives, or by Budowski (1982) with regard to biological as well as to socioeconomic aspects. Greatly simplifying their detailed considerations, it can be said, on the beneficial side, that agroforestry is "ameliorative and protective" that is, it can increase, diversify, and sustain crop production while improving environmental stability (de la Cruz and Vergara 1987). On the detrimental side, trees can be or be seen to be competitive - either economically or biologically or both - with annual-crop production rather than complementary or supplementary. Consequently, when farm size falls below a certain level, farmers may forego tree products and services in favour of staple food-crop production. Or if land tenure is not secure, the time-lag in realizing benefits gained by planting trees may become a severe disadvantage, and trees will not be planted or pro tected. Sustainability is not common sense if there is no future return to the individual on today's investment in conservation or long-term production. Also, trees hinder mechanization, and their establishment or maintenance may require more manual labour than is easily available.
All this is no more than to say, as has been observed by many authorities, that agroforestry is not a panacea. Policies promoting agroforestry may demand costs from those who will not receive the benefits. Planning for agroforestry becomes very complex if it takes into consideration the incongruencies that may exist between ecological and economic accounting or if it seeks to resolve the issues of equity that promotion of agroforestry may cause across time and between social sectors or between the individual and the community.
Looking specifically at the Pacific, Künzel (1989, 24-27) has pithily expressed the doubts raised by Tongan farmers about agroforestry. While recognizing the antiquity of their agroforestry tradition and appreciating the benefits of trees, the farmers also made the following points, which Künzel relates as though they were in a letter from a Tongan farmer:
I have farmed my land for all my life, and it has been a constant struggle against trees. Before I can plant any crops, I have to remove the trees. The more trees I remove, the more crops I can plant. It is our saying that good farmers have neat fields, which means neatly cleared. Trees are for the lazy. True, there have been less trees in recent years than when I was young, but this does not change the wisdom of our forefathers.
Of course trees make the soil more fertile, but this takes many years. During the few years that I need to cultivate a certain area, trees only shade out my food crops. I learnt to live with that while I had to clear my field by hand. Ecologists always marvel at the systems I developed. But now that I can hire a tractor easily, I clear my trees with enthusiasm. Believe me, it improves the yield.
The building materials, perfumes, medicines and dyes I get from trees are old-fashioned and ineffective.... I like those products from overseas.... Nobody is boiling tree bark to fight a stomach ache in New York. Pills work better, and I want to use them too.
If I cut a tree, I reap the benefits completely and immediately. If I plant a tree, who knows the person who will benefit? Probably not me, and maybe not my children.
Young trees are more vulnerable than young onions! One week when I have no time to water, or a runaway cow while I sleep, and all is gone. Not to mention fire. I do not like risks like that.
Finally, all the arguments about the ecological benefits of trees are de finitely true. But when the day starts and I have to decide whether or not to plant cassava or trees for my family, a day planting cassava is worth more.
These views of a fictitious Tongan farmer clearly provide reasons for current agrodeforestation. They also remind us that the first purpose of agricultural or agroforestry systems is the production of goods that have value for the farmer, not the maintenance of agro-ecosystems in a healthy and sustainable state. In today's Pacific, the production of goods with value is affected not only by rapid population growth in many countries but also by a whole range of nontraditional factors such as mechanized technology, monetization, a never-ending search for new export products, individualization, wage-paying employment, and new forms of communication in combination with advertising. Agroforestry often fits uneasily with these changes. Although everyone agrees that agroforestry has great contributions to make to biological and physical sustainability, many people have doubts about its social and economic benefits. As Künzel (1989, 27) says: "Clear and convincing reasons why agroforestry will benefit the individual farmer need to be found."
The relationship between the individual farmer and the larger community is in many ways analogous to the relationship between an individual landholding and the landscape in which it is situated. To maintain the landscape in good health, it is not necessary that every landholding, every stretch of land, contain trees, just as every farmer need not be an agroforester- but it is necessary that there be sufficient trees in the right places, at the least on sloping land and along streams. However, the predicament in the Pacific, as in much of the world, is that the landscape is not a unit of management even though it best expresses the integration of environmental processes and relations at the regional level. Governments everywhere are only now starting to grope toward the concepts of landscape ecology, a groping that may be motivated by demands to make development sustainable but that is - to be more optimistic- facilitated by the modern tools of computer databases and remote sensing of the environment. None the less, bringing the science of landscape ecology into land utilization and management is a difficult and slow process, for landscape ecology cuts across economic sectors and encompasses traditionally distinct agencies or ministries, such as agriculture, forestry, and urban planning (Naveh and Lieberman 1984). When this inertia is combined with population growth, with economic pressures, and with the complex issues of land tenure and of multiple control over land use, it is no wonder that implementing conservation measures is often difficult or that agrodeforestation is taking place. Even within this context, however, there are ways to plan for agroforestry, to encourage it, and to slow down agrodeforestation. These will be discussed later in this chapter. First, we will turn to a brief consideration of the basic component of Pacific Island, or any other, agroforestry systems - the trees themselves.
The case-studies in this book illustrate the richness of the existing heritage of polycultural agroforestry possessed by all Pacific societies, both rural and urban, both predominantly subsistence and strongly focused on cash-crop production. By definition, it is trees and tree-like species that are fundamental to these almost endlessly variable systems. If the existing systems are to be preserved and utilized in future agroforestry development, it is of course necessary to preserve the trees themselves as well as to have an inventory of information about them. Analysis of available information from the literature and field surveys has led to the identification of 419 cultivated and/or wild tree or tree-like species or groups of closely related species that are of widespread or localized economic, cultural, and ecological importance in Pacific Island rural and urban agroforestry systems. As these plants have already been shown to be useful components of local agroforestry systems, they merit consideration for future use, but to discuss here, or even to list, all 419 species or groups of species would be impractical as well as daunting to all but the most botanically-minded of readers. In place of that overload of information, we discuss here only a few arbitrarily selected details. In the Appendix, the characteristics and uses of 100 Pacific Island agroforestry trees are described more fully so as to provide the interested reader with a picture of the rich variety of species available.
Selection of agroforestry resources
Whether on high islands, with their often rich soils, varied habitats, and low population densities; on the harsh atolls almost without soil and short of water; or in home gardens in densely settled urban areas and monocultural rural agricultural areas, Pacific Islanders have selected for incorporation into their agroforestry systems a wide range of tree and tree-like species that meet their particular en vironmental and cultural needs. The use of these species is the cumulative result of a selection process that has occurred over thousands of years, beginning in the ancestral homelands of today's Pacific Islanders in SouthEast Asia and the archipelagic areas of Indonesia, the Philippines, and Papua New Guinea, whence valuable cultigens and accumulated knowledge of wild species were transferred to the smaller Pacific oceanic islands.
After they arrived, early settlers domesticated previously unknown indigenous species or else incorporated them as wild species into agroforestry systems prior to European contact (Yen 1990). Similarly, post-Europeancontact introductions, including food plants, timber trees, and ornamentals have been tested, selected, and incorporated into today's systems to such an extent that the undiscerning visitor or agricultural "expert," and many of the current generation of islanders, believe the introduced trees to be traditional or even indigenous. The integration has been carried to such an extent that the status of many species remains unclear as to whether they are local domesticates or indigenous plants, aboriginal introductions brought to the islands by successive waves of Pacific settlers, or early postEuropean-contact introductions.post-European-contact
Of the 419 agroforestry plants, approximately 329 are classified as large or small tree or tree-like species, whereas approximately 90 are smaller, more shrub-like perennials, which constitute common fixtures in Pacific Island agroforestry systems. The division into shrubs and trees is, of course, somewhat arbitrary because some species, depending on the environment, the variety, or cultivar, can be either shrubby or tree-like. For example, the species Hibiscus tiliaceus, Pipturus argenteus, and Vitex trifolia are all found as both shrubs and trees. Similarly, groups of highly variable, closely related species of the genera Leucosyke, Pandanus, Pittosporum, Psychotria, Solanum, and Timonius are all represented by both shrubs and trees.
A very limited sampling of shrubs and shrub-like species would include the indigenous, often wild, plants such as Acalypha insulana, Dodonaea viscosa, and Pemphis acidula. Important food or beverage plants in the "shrub" category include the bush hibiscus spinach (Hibiscus manihot); sugar cane, which, along with the related species with the edible inflorescence (Saccharum edule), forms tree-like stands in Pacific gardens; kava (Piper methysticum), the important social bev erage of Vanuatu, Fiji, Polynesia, and Pohnpei; betel pepper (Piper belle), which is cultivated in western Melanesia, high-island Micronesia, and by the Indian community of Fiji. Shrubby handicraft plants of a widespread importance include paper mulberry (Broussonetia papyrifera), which extends from the highlands of Papua New Guinea, where it is used in the production of string bags (bilum) and a wide array of loin cloths, to Polynesia, where it is used in the production of the ceremonially important tape cloth, an increasingly valuable source of cash income from the tourist industry; and a wide variety of Pandanus species or cultivars, whose leaves are used in plaited ware such as fine mats, thatching, hats, baskets, and other items of cultural and economic importance. The rattan palms (Calamus spp.) are important in Papua New Guinea for handicrafts and general construction. The introduced annatto (Bixa orellana) is widely planted for its seeds, which yield a red dye, and has been a minor smallholder export crop in Western Samoa.
"Protective" or magical plants, established in or around active garden areas to ward off evil spirits, include Cordyline fruticosa, Coleus scutellarioides, and Euphorbia fidjiana, which may be present only in Fiji and Tonga.
Origin or antiquity status
Of the 419 species, approximately 172 (41 per cent) are probably indigenous to most islands where they are found; 13 are probably aboriginal introductions; 40 either indigenous or aboriginal introductions; 147 (35 per cent) are recent post-European-contact introductions; 17 are indigenous in some areas but recent introductions in other areas; 17 are both aboriginal or recent depending on the area; and 13 are indigenous, aboriginal, or recent depending on the area. It is, however, extremely difficult to determine whether some species were indigenous or introduced by early settlers, and their status may be different in different areas. For example, Terminalia catappa may be both indigenous and/or an aboriginal introduction to some areas, whereas it is probably a recent introduction into Hawaii.
The 172 possibly indigenous species include plants from Pacific Island coastal strand forest, mangrove forest, marsh or riparian and indigenous lowland, and montane forest, as well as pioneer species common in fallow vegetation. All are important components of plots of relatively undisturbed vegetation bordering or included in agroforestry systems and are often deliberately protected or planted as in tegral components of rural gardens or plantations and urban gardens because of their cultural and ecological utility.
Of the more than 80 species that may be aboriginal introductions to at least some islands, the most widespread and culturally important species are food plants. These include the ubiquitous "tree-of-life" coconut palm, breadfruit, the many traditional banana and plantain cultivars, sago palm, edible pandanus cultivars, sugar cane, bush hibiscus spinach (Hibiscus manihot), and a variety of fruit and nut trees and other supplementary food crops.
Also, almost certainly aboriginal introductions to most areas were the important social masticant and beverage plants, betel-nut palm (Areca catechu) and betel pepper (Piper belle), kava (Piper methysticum); the important fibre and handicraft plants, paper mulberry (Broussonetia papyrifera) and a wide range of Pandanus species or cultivars; the candlenut (Aleurites moluccana) and the perfume tree (Cananga odorata), so highly valued for scenting coconut oil; and a wide range of other plants of cultural value for general construction and boat building, medicines, dyes, poisons, fibre, perfumes, decorations, magic, and other purposes.
The recent post-European-contact introductions include important longestablished food trees such as the papaya, mango, avocado, a range of Citrus species, guava, soursop, sweet sop, and three important commercial banana clones; the ubiquitous perennial chill) pepper; food trees of more localized importance, such as the jakfruit, tamarind, horseradish, or drumstick, tree (Moringa oleifera), and the Indian bay, or curry leaf (Murraya koenigii), all of particular importance to the Indian community of Fiji; and a wide range of fruit and nut trees of minor importance. (See the Appendix for further details on some of these plants.)
Recent introductions of commercial importance include tea, coffee, oilpalm, Para rubber, cocoa, and new, often high-yielding, cultivars or clones of plants such as the coconut palm, bananas, and citrus trees; the exotic timber species including Cordia alliodora, Eucalyptus deglupta, Caribbean pine (Pinus caribaea), and West Indian mahogany (Swietenia macrophylla); and a number of other species that are, or will be, important sources of income to some countries in the region.
Other recent introductions include the common bamboo, cotton, kapok, the neem tree (Azadirachta indica), allspice and bay rum tree (Pimenta doica and P. racemosa), and castor bean (Ricinus communis); a number of fastgrowing multi-purpose trees, most notably
Leucaena leucocephala, madre de cacao (Gliricidia septum), Pithecellobium dulce, Sesbania grandiflora, Erythrina spp., and Jatropha curcas; a wide range of exotic ornamental trees and shrubs, the most common including the orchid tree (Bauhinia spp.), bougainvillea, flowering cassias, poinciana, or flamboyant, banyans (Ficus spp.), gardenias, lantana (Lantana camara), Persian lilac, or China berry (Melia azedarach), mock orange (Murraya paniculata), the ubiquitous plumerias, or frangipanis, monkey-pod, or rain tree, and the African tulip tree; and a number of widely cultivated ornamentals, such as Acalypha amentacea, Codiaeum variegatum, Gardenia taitensis, Graptophyllum pictum, hedge panaxes (Polyscias spp.), and Pseuderanthemum spp. A number of palms, although recent introductions into the eastern parts of their range, are possibly indigenous to or even domesticates of Melanesia or Polynesia.
All 419 plants or groups of plants are found in the diverse agroforestry environments of either high islands or the larger limestone islands, with no species of widespread or major local importance confined to the atoll environment. Only 83 species (20 per cent) are commonly found on Pacific atolls, which reflects both the poverty of the indigenous and exotic floras on atolls as well as the critical importance of all agroforestry species that do succeed in growing on atolls. Of these 83 species, 30 are ubiquitous Pacific strand or mangrove species, 26 are introduced ornamentals, with the balance consisting of aboriginally introduced plants, recently introduced food plants, and a small number of recently introduced timber, fuel-wood, or other useful plants.
Of the 419 agroforestry plants, some 113 are found almost exclusively in a wild state, 127 are cultivated, and about 179 are both cultivated and wild. The 113 exclusively wild or uncultivated species are made up of indigenous coastal strand, mangrove, and inland-forest species commonly protected in forest stands. Also included are several pioneering species that, although not generally protected when clearing new garden plots, are encouraged through selective weeding and become dominant components of the young fallow forest.
The strictly cultivated species, on the other hand, are almost entirely exotic cultigens. These include major and minor fruit or food species, ornamentals, exotic timber or fuel-wood species, major and minor export crops, and a number of handicraft, medicinal, spiritual, and other multi-purpose species.
Species found both cultivated and in a wild state include a wide range of indigenous species, which are also deliberately cultivated, as well as cultigens, most of which are exotic, that have escaped or become naturalized and are seen to have significant cultural or ecological value. Among the most commonly cultivated indigenous species are a large number of ubiquitous coastal strand plants valued for their multi-purpose utility. Some trees indigenous to Melanesia in the genera Acacia, Agathis, Albiza, Araucaria, Endospermum, and Terminalia have been deliberately planted or experimented with as timber species for reforestation programmes.
Species that are both cultivated and either commonly naturalized or indigenous include food species such as coconut, breadfruit, sago palm, sugar cane, Saccharum edule, and Cordyline fruticosa. Other food trees in this category are Adenanthera pavonina, Barringtonia spp., Burkella obovata, Canarium spp., Castanospermum australe, Corynocarpus similis, Dracontomelon vitiense, edible figs (Ficus spp.), Finschia chloroxantha, Gnetum gnemon, Musa troglodytarum, Pangium edule, Pometia pinnata, and Syzygium malaccense. Other cultigens found wild are candlenut (Aleurites moluccana), betel-nut and betel pepper, perfume tree, or ylang ylang (Cananga odorata), Schizostachyam glaucifolium, Sida fallax, and Solanum uporo. Most of these species are commonly found in mature fallow forests, where they are either remnants of former cultivation or naturalized escapes or volunteers that have either been protected by agriculturalists or, in some cases, may have been components of the indigenous flora.
Recent post-European-contact introductions that have become most widely naturalized, commonly as escapees from cultivation, include the perennial chill) pepper, papaya, lantana, leucaena, and guava. Other commonly naturalized species include Acacia farnesiana, Brassaia actinophylla, Cassia alata, citrus trees, derris root, mango, Melia azedarach, and castor bean. There are others of more localized importance, many of which are either selfsown or have grown from seeds discarded by humans. Although growing wild, most of these species cannot be considered fully naturalized as they grow mostly in disturbed sites and are generally displaced by indigenous vegetation in mature fallow forests.
In terms of relative importance, 56 of the 419 species are considered to be of major agroforestry importance in many island groups in terms of abundance and/or ecological importance and cultural utility. These include:
Table 11 Tree or tree like species or groups of closeb related species of mqior agroforestry importance in certain localities and/or widespread supplementary ecological or cultural importance (See Appendix for detailed information on some of the species listed here)
|Acalypha amentacea vars.||Diospyros samoensis||Musa troglodytarum|
|Adenanthera pavonina||Diospyros spp.||Musa cultivars|
|Aglaia saltatorum||Dracontomelon vitiense||Myristica spp.|
|Aglaia spp.||Dysoxylum forsteri||Neisosperma|
|Albizia lebbeck||Elaeis guineensis||Nerium oleander|
|Alphitonia spp.||Flaeocarpus spp.||Pandanus conoideus|
|Alyxia spp.||Endospermum spp.||Pandanus dubius|
|Annona squamosa||Eucalyptus deglupta||Pandanus julianettii|
|Antiaris toxicaria||Eucalyptus spp.||Pangium edule|
|Araucaria cunninghamii||Euadia hortensis||Parinari glaberrima|
|Araucaria heterophylla||Euodia spp.||Pemphis acidula|
|Artocarpus heterophyllus||Ficus benjamina||Persea americana|
|Artocarpus mariannensis||Ficus copiosa||Phaleria spp.|
|Barringtonia asiatica||Ficus dammaropsis||Pinus caribaea|
|Barringtonia edulis||Ficus obliqua||Pisonia grandis|
|Bauhinia monandra||Ficus tinctoria||Planchonella spp.|
|Bougainvillea spp.||Ficus wassa||Plumeria obtusa|
|Burkella obovata||Ficus spp.||Polysciasfruticosa|
|Cajanus cajan||Garcinia sessilis||Polyscias scutellaria|
|Canarium indicum||Garcinia spp.||Prichardia pacifica|
|Canarium spp.||Cardenia jasminoides||Pterocarpus indicus|
|Cassia alata||Cardenia taitensis||Rhus taitensis|
|Cassiagrandis||Cliricidia sepium||Santalum spp.|
|Casuarina oligodon||Gnetum gnemon||Scaevola sericea|
|Cerbera manghas||Grewia crenata||Schizostachyum|
|Citrus aurantiifolia||Heliconia indica||glaucifolium|
|Citrus aurantium||Hernandia||Securinega flexuosa|
|Citrus grandis||nymphaeifolia||Sida fallax|
|Citrus limon||Homalanthus spp.||Solanum melongena|
|Codiaeum variegatum||lntsia bijuga||Spathodea campanulata|
|Coffea arabica||Ixora spp.||Sterculia spp.|
|Coffea canephora||Jatropha curcas||Swietenia macrophylla|
|Coleus scutellarioides||Kleinhovia hospita||Syzygium cumini|
|Commersonia bartramia||Lantana camara||Syzygium richii|
|Cordia alliodora||Lumnitzera littorea||Syzygium spp.|
|Cryptocarya spp.||Melaleuca leucadendra||Tamarindus indica|
|Cycas circinalis||malabathricum||Terminalia spp.|
|Decaspermum fruticosum||Metrosideros collina||Tournefortia argentea|
|Denrocnide spp.||Micromelum minutum||Trema spp.|
|Derris spp.||Moringa oleifera||Vitex spp.|
Also of major agroforestry importance, although not quite as widespread or as abundant in indigenous agroforestry systems, are another 125 species or groups of closely related species. These include:
If all the individual plants belonging to the over 400 species of agroforestry trees and shrubs should suddenly vanish, Pacific Island landscapes and life would be dramatically altered, and a near irreplaceable resource would have been lost. The manifold utility of the agroforestry species has been stressed throughout this book. They fulfil cultural, economic, and ecological functions, with the majority of species serving multiple purposes, as shown by a study of coastal species commonly found in Pacific Island agroforestry systems. On average, each species had 9.2 purposes or uses, ranging from two reported uses per species to as many as 121 for the coconut. These uses did not include the strictly ecological functions such as shading, protection from wind and sand and salt spray, erosion and flood mitigation, coastal reclamation, provision of animal and plant habitats, or soil improvement (Thaman 1989c).
We have already suggested the paradox to be seen in the concurrent existence, on the one hand, of a rich indigenous agroforestry resource containing both a great variety of component trees and an extensive and sophisticated body of knowledge and, on the other hand, institutional proposals for the introduction and development of agroforestry. This incongruous situation is partly the result of the tendency of development specialists to promote the currently popular "solution', before the problem has been carefully investigated. It is also, as we have argued earlier, simply a lack of knowledge in institutional circles with regard to indigenous agroforestry. Even at the recent technical meeting on Pacific Island agroforestry held in Western
Samoa (Clements 1988), few of the speakers (mostly Pacific Islanders) appeared to recognize that in areas of shifting (swidden) cultivation the forest had any function other than fallow. The intricate, usually intentionally created, multi-purpose character of secondary forests described in this book received little attention - except for the discussion of Pohnpei's "agroforests" and an occasional mention of fruit or nut trees elsewhere.
As the combined pressures of population growth and cash cropping bring shortened fallows, declining soil fertility, and increasing cultivation on marginal lands to many of the Pacific's high islands, institutionally promoted systems such as contour hedging with Leucaena, Gliricidia, or Calliandra can help maintain soil fertility and lessen erosion, as has been clearly demonstrated elsewhere in the world. It should be recognized, however, that the process of replacing the indigenous agroforest with a few, usually exotic, species, useful though they are, is part of the pattern of simplification of subsistence systems in the Pacific (Ward 1986, 218) and loss of general biodiversity that is often seen as one of the great ecological threats of the present world. While the forces driving toward simplification and loss of natural forest and indigenous agroforest cannot be easily slowed, some interventions may help.
Appreciation of indigenous agroforestry
If indigenous agroforestry is to be encouraged, the character and value of the many existing agroforestry systems need to be more widely and deeply appreciated. As it is to that purpose that the material in this book is largely dedicated, we will only recapitulate a few of the worthwhile and significant technologies and characteristics that need to be kept in mind with regard to Pacific Island agroforestry.
The composite extended nature of agroforestry systems
In the land-use strategy of Pacific Islanders almost all types of agricultural or wild lands are viewed as integral components of a larger agroforestry system. This view should be taken into consideration during development planning. Types of agricultural and wild lands found within the matrix of agroforestry systems include: native or secondary forest stands; sacred groves; monocultural woodlots, orchards, or coconut, cocoa, or oil-palm plantations; mixed tree- and ground-crop shifting agricultural plots; home gardens; and even small patches of grassland or adjacent mangrove or coastal forest.
Just as an entrepreneur wisely diversifies his assets, the Pacific agroforester diversifies his or her land use, both within individual plots or areas, or within the whole set of landholdings to which the agroforester or his or her extended family have usufruct, individualized, or even freehold (fee-simple) rights. Thus, any suggested changes or innovations to a given part of the system will affect the system's aggregate utility, stability, and sustainability.
Home gardens in agroforestry systems
Throughout the Pacific, home gardens are integral components of agroforestry strategies. They may exist as adjuncts to wider rural or village agroforestry systems, or stand on their own as urban home gardens. They are also among the most diversified and most dynamic agroforestry systems, often serving as both refugia for endangered or culturally-important traditional species, as well as avenues for the introduction and testing of new exotics. As suggested by Thaman (1988g), the promotion of urban and home gardening may be among the most cost-effective and culturally and ecologically appropriate means of satisfying many of the commonly stated objectives of national development plans.
High interspecies diversity
All traditional agroforestry systems, from the highlands of Papua New Guinea to the smallest atoll countries, are truly polycultural, exhibiting a high degree of interspecies diversity incorporating a wide range of cultivated, protected, and wild indigenous and exotic species. The numbers of species range from some 75 commonly encountered on atolls, which have among the poorest floras on earth, to over 300 widespread species found in the agroforestry systems of the larger islands of Fiji, Vanuatu, the Solomon Islands, and Papua New Guinea.
High intraspecies diversity
There is, additionally, a high degree of intraspecies diversity for most traditional tree and non-tree cultigens and for many recently-introduced cultigens. A wide range of named, locally-differentiable cultivars, varieties, or "land races" (Harlan 1975) exists for a given species. Within a given species, these cultivars have variable yield characteristics and seasonality, thus spreading yield distribution and seasonal surpluses more evenly. Different cultivars also have differential resistance to pests and diseases, tropical cyclone damage, salt water incursion and salt spray, and drought; differential ecological tolerance ranges in terms of adaptability to different soil types, shade, and hydrological regimes; and differential utility (for example, some coconut cultivars are used purely as drinking nuts, some for the flesh, and some for the large shells or the coir, which can be used for vessels or for cordage, respectively). As indicated in the case-studies, there is a particularly great range of cultivars of the traditional staple tree crops of coconut, breadfruit, pandanus, and banana and plantains; traditional perennial supplementary crops like sugar cane, sugar cane inflorescence (Saccharum edule), and hibiscus, or bush, spinach (Hibiscus manihot); traditional non-food plants, such as kava (Piper methysticum) and betel-nut (Areca catechu); recent introductions such as papaya, avocado, and a range of Citrus species; and many indigenous or, in some cases, possible aboriginally-introduced food and non-food species, such as Pandanus tectorius, Pometia pinnata, Hibiscus tiliaceus, Erythrina variegate, and a number of species of Ficus, which seem to have undergone systematic selection by the indigenous inhabitants of various islands and are now represented by a range of recognized cultivars or semi-domesticated genotypes.
Importance of wild food resources
Wild food resources are among the most important products of agroforestry systems, particularly in Melanesia, where extensive stands of primary and secondary forest remain. Most notable among these are a great diversity of wild yams, ferns, fungi, fruits, nuts and leaves and birds, frogs, snakes, grubs, insects, fin fish, eels, freshwater prawns, and other foods that are found within agroforestry zones. Even in grassland areas and on atolls, wild yams, ferns, wallabies, kangaroos, birds, edible plants, and crabs constitute important wild or emergency food resources. Apart from being nutritionally important, these wild products also constitute important low-capital-input, lowrisk seasonally abundant cash crops. When forests and trees are removed, however, in the process of agricultural intensification or replanted with exotic silvicultures, species diversity of wild plant and animal foods decreases significantly (Clarke 1965; Watling 1988), thus constituting a loss of food resources and cash and non-cash income.
Live fencing, hedges, animal pens, and boundary markers
Of almost universal importance is the use of live fencing, hedges, and boundary markers, which serve as productive and ecologically valuable components of agroforestry systems. The use of trees or shrubs for such purposes includes: living fence posts for modern barbed-wire fencing on livestock development schemes or around crops susceptible to damage by livestock; boundary markers demarcating boundaries of land parcels belonging to different landholding groups, between the active gardens of individual gardeners, or between individual plots within a given gardener's active garden area; wind-breaks or barriers to protect coastal gardens from salt-laden air and resultant physiological drought and excessive salinity; and living animal pens, either with or without wire.
Integration of livestock and agroforestry
A common characteristic of most traditional agroforestry systems is an integration with, rather than a segregation or dissociation of, agroforestry from livestock husbandry. Domesticated pigs foraged in secondary forests and woodlands during the day and were also fed forest products to supplement their root-crop diet. Moreover, traditional systems often provided a means of storing surplus crop production for times of scarcity or feasting, such as in highland Papua New Guinea, where pig production served this purpose (Bayliss-Smith 1982). The increasing institutional emphasis on smallholder cattle projects, modern piggeries, and battery-raised poultry seems to be riddled with failure, compared to traditional foraging, waste-disposal, or tethering systems. Notable exceptions include cattle under coconuts, which seem to be far less productive than crops under coconuts (Schirmer 1983, 104), and cattle under timber trees. Evidence from throughout the Pacific shows that the modern intensive systems are extremely difficult to maintain, and in the case of smallholder commercial grazing systems, have caused widespread destruction of food crops and agrodeforestation (Grossman 1981).
Value of trees as staple crops
Throughout the Pacific, trees or tree-like crops constitute major or supplementary staples. The coconut, for example, is the major source of dietary energy on atolls, and in some coastal areas. Bananas and plantains, as a group, are perhaps the most important staples, after taro, cassava, and sweet potato, in terms of total calories provided to Pacific societies, with breadfruit being a particularly important seasonal staple in most areas. Other, lesswidespread or major seasonal staples include edible pandanus (Pandanus spp.), Tahitian chestnut (Inocarpus fagifer), and Barringtonia and Canarium spp. Such renewable (without replanting) energy resources are of particular impor tance, given that in parts of Melanesia, energy deficiency and not protein deficiency is the most serious nutritional problem and that increasing food dependency on imported white flour and rice, in both urban and rural areas, is a serious economic and nutritional problem (Coyne 1984; Hayward and Nakikus 1982; Jeffries 1979).
Trees as major sources of micronutrients and fibre
Along similar lines, fruit-trees, nut trees, leaf-providing trees such as Hibiscus manihot, Ficus spp., Gnetum gnemon, and Moringa oleifera, and sugar cane are some of the best sources known of vitamins, minerals, fibre, and other micronutrients, so vital to optimum health, but often lacking in modern urban diets. The increased consumption of such foods could significantly address increasingly widespread incidences of micronutrient deficiencies, such as anaemia and vitamin-A and vitamin B-complex deficiencies.
Medicinal importance of trees
The strategic importance of agroforestry systems as sources of the medicines used by many rural and urban people, most of whom have no access to or could not afford imported medicines, cannot be stressed too strongly. The importance of medicinal plants in agroforestry systems is underlined by the very high numbers of medicinal plants found in home gardens, in garden areas, and in protected forests or tree groves. Some two-thirds of medicinal plants are trees or shrubs (Thaman 1988g; 1989c).
Tree products of subsistence and commercial value
In addition to foods and medicines, trees are the sources of a very wide range of construction and handicraft materials, cordage, dyes, poisons, scents, oils, decorations, and body ornamentation, and an almost endless range of utilitarian products of considerable subsistence and commercial value. Such products account for a significant proportion of real rural and poor-family urban incomes, incomes that are little affected by inflation or the vagaries of an unstable world economy.
Magico-religious and spiritual importance of trees
The magico-religious or spiritual importance of trees, both in terms of sacred groves or individual living trees and the use of plant parts in magic or ceremonies, particularly in Melanesia, is an important aspect of Pacific Island agroforestry, and a reason for preserving trees. Ceremonial uses of plants include ceremonies or rituals associated with death, war and peace, human sacrifice and cannibalism, circumcision or coming of age, canoe making and launching, fishing, planting cycles, prayer sessions, as well as species serving as symbols or totems or planted in sacred groves or burial grounds and mediums for communicating with spirits or gods. Others are associated with times of revelry or are used in the production of baskets, mats, and other articles reserved for ceremonial exchange or dress. Many plants also feature prominently in Pacific Island mythology, legends, songs, riddles, proverbs, and cosmogony. As recorded in Ethnobotany of the Samoans (Setchell 1924), plant names were given to gods or vice versa, and songs and legends have developed around them and the "heroes, families, or villages, etc. they represent." One particular Samoan text of the "battle of trees and stones" enumerates between 70 and 80 tree names. Also very closely related to ceremony and ritual are magic and sorcery, which are still very strong in the Pacific, especially in Melanesia and parts of Micronesia. Plants are integral to such practices, which include magic related to love, exorcism of evil spirits, gardening, and death (Thaman 1989c).
Protection, pruning, and pollarding of trees during garden preparation
Protection (not killing) of trees, although often with severe pruning or pollarding, in the preparation of new gardens, or when replanting old gardens, is a widespread practice that ensures the stability of agroforested landscapes. The ringbarking or removal of trees, often to allow for total tillage or ploughing, so commonly promoted to maximize the production of a single target crop, is a major factor in agrodeforestation. Not only does severe pruning or pollarding of valuable species such as Bischofia javanica, Hibiscus tiliaceus, and Macaranga spp., and fruit-trees such as mango, citrus, and Pometia pinnata, open up prospective garden areas to sunlight and provide additional organic material, and ash if gardens are burned, it also ensures renewed vigour of the regrowth and provides firewood and trellising for crops. Even ringbarking, if done in a particular way, will stimulate shooting from the base, thus not permanently eliminating a given tree from the garden area.
The practice of minimum or restricted tillage and the use of appropriate hand tools, which minimize soil degradation and favour the survival of trees, are universal and beneficial features of shifting agro forestry systems. It is especially important in the humid tropics and in steep terrain where heavy rainfall and high temperatures promote rapid leaching and oxidation and/or accelerated erosion of loosened soils. The practice of minimum tillage, where holes or mounds are prepared or the soil loosened only where plants are to be planted, is, thus, a positive, but labour-intensive, alternative to complete tillage or ploughing. Although appropriate in laboursurplus areas throughout the Pacific, the practice is being abandoned in areas such as Tonga and the Cook Islands, where ploughing and disc harrowing is encouraged in commercial monocultural production of root crops, vegetables, and fruits such as water melon and pineapple.
Mulching, composting, and fertilization
The use of leaves and other plant parts for mulching, composting, and fertilization in the cultivation of major staples and tree crops, particularly on atolls, is a well-developed practice that depends on the maintenance of a range of often minor non-food plant species found in agroforestry systems. In Melanesia, intensive mulching systems using the leaves of Pometia pinnata are employed in the East Sepik area of Papua New Guinea (Allen 1985), and a wide range of leaves are placed in planting holes of yams and taro or dug into the mud in irrigated taro gardens in Vanuatu, often to aid in insect or pest control, to enhance taste, or as part of diverse, but possibly functional, magicoreligious rites. Throughout the Pacific, various societies, such as the Koita in the arid savanna areas near Port Moresby, Papua New Guinea, deliberately mulch yam, cassava, taro, and sweet potato gardens with dried grass and other plant remains to reduce moisture loss and erosion and to improve soil fertility and yields. It is in Micronesia, in the harsh, almost soil-less atoll environment, that mulching systems are the most intensive. The most sophisticated systems are those used in the production of the ceremonially important giant swamp taro (Cyrtosperma chamissonis), with a wide range of leaves, some specially processed and dried, being mixed with scarce topsoil from under deliberately protected plants, and applied in woven pandanus or coconut frond baskets. Pulverized, rooted coconut logs, seaweed, pumice, and tin cans or rusting iron are also occasionally added to provide additional benefits, trace elements, or to alter the soil pH to free trace elements. The use of kitchen waste, animal manure, and ash is increasingly widespread in urban and home gardens, with mill-mud (waste from the sugar refining process) being used in some areas of Fiji (both on sugar-cane farms and in home gardens). Commercial inorganic fertilizers are only rarely, if ever, used in most existing agroforestry systems.
The practice of selective weeding to encourage culturally useful and important pioneer fallow species, particularly in the later stages of fallow, is a widespread characteristic of most agroforestry systems. Through such practices, fallow species and non-planted volunteer seedlings of other useful plants, such as mangos, papaya, citrus, and nut trees, can be selectively encouraged during the latter stages of the gardening cycle, thus hastening and controlling or managing the formation of productive tumbledown fallows and fallow forests or orchards, often including still productive stands of cassava, yams, taros, and bananas and plantains.
Permanent polycultural orchards
The establishment of permanent polycultural orchards, which often become mixed fallow forests, is a widespread practice. Such orchards, which may be almost entirely planted or may be mostly mature fallow forests in old gardening areas where useful trees had been planted, are protected as permanent productive features in the agroforestry landscape. The orchards can take the form of communal groves adjacent to villages or they can be individually-controlled groves in distant garden areas. The species composition varies from area to area, with a wide range of fruit, nut, and other useful trees represented, e.g. the Pandanus-breadfruit-Gnetum-Ficus wassa orchards described for the highland fringe of Papua New Guinea.
Planting, transplanting, or protection of indigenous species
It is a widespread practice to plant, transplant, or protect indigenous species in agricultural areas and in urban and home gardens. Coastal strand species such as Barringtonia asiatica, Calophyllum inophyllum, Casuarina equisetifolia, and several others are often thus cared for, as are important food trees such as Canarium spp., Ficus spp., lnocarpus fagifer, and Pometia pinnata.
Domestication or semi-domestication of indigenous species
Related to the deliberate planting of indigenous species was the domestication or semi-domestication of many of these same indigenous species. This was particularly the case in non-Austronesian areas of Melanesia (Kirch and Yen 1982; Yen 1976a; 1974). Included in this Pacific Island domestication were Burkella spp., Calophyllum inophyllum, Casuarina equisetifolia, Hibiscus tiliaceus, Nersosperma oppositifolium, Pipturus argenteus, and Pometia pinnata, which came to contain a range of cultivars or genotypes and were deliberately planted in gardens and for coastal stabilization.
Improved fallow systems based on deliberate planting of soil enhancing species was practiced in some areas, particularly in places in Papua New Guinea where agricultural intensification was far advanced. There, indigenous Casuarina spp. are deliberately planted as improved fallows and to provide fuel wood and fencing when cleared for the next garden. Albizia falcataria and Dodonaea viscosa are also planted to improve fallow in highland New Guinea. Guettarda speciosa and Tournefortia argentea are occasionally planted or encouraged to improve soils on atolls. A similar strategy has been adopted institutionally on Rarotonga in the Cook Islands, where Leucaena leucocephala, Albizia falcataria, Casuarina equisetifolia, and Eucalyptus spp. have been planted to rehabilitate degraded upland areas.
The productivity, sustainability, and adoptability of indigenous systems
The summary descriptions above of some technologies and characteristics of indigenous agroforestry systems serve to illustrate again the depth of knowledge and sophistication associated with the use of trees in the Pacific. The experts who understand, developed, and manage the systems - i.e. the local people - are already in place, "incountry," in the jargon of expatriate consultants. Formal experimentation and training might well improve the systems, but clearly, as noted in chapter 1, they possess already the criterion of adoptability, which, along with productivity and sustainability, is listed by Raintree (1990, 58) as one of the basic criteria possessed by any well designed agroforestry system. Similarly, that the systems are already local means that they meet the normative condition established by Bene et al. (1977); namely, that an agroforestry system be "compatible with the cultural patterns of the local population." As Raintree (1990, 92) says with regard to the introduction of agroforestry technologies, "there is little value in originality for its own sake" - espe cially when the local knowledge base is as immense as it is in the Pacific Islands. All of this suggests that encouraging local agroforestry systems would directly satisfy one of the currently most popular imperatives of development: community participation and concern with location-specific needs and opportunities (e . g., Chambers 1983).
Turning to Raintree's (1990) other two criteria, clearly the local systems possess adequate productivity or they would not have been maintained for so long. Indeed, archaeological and other evidence now supports the view that arboriculture has been practiced in the western Pacific for millennia (Yen 1990). Similarly, the systems possess sustainability and stability - even though they are dynamic - both in the sense that production has been maintained and that the environment has been protected if not enhanced. But being successful in the test of time does not mean that agroforestry systems achieve a high level of economic efficiency by modern measurements. The truth is of course that no matter how valuable the systems are believed to be, indisputable measurements are difficult to obtain. If we examine the anti-arboreal view of Künzel's composite Tongan farmer discussed at the beginning of this chapter, we can only agree that on a single field, planting or maintaining trees may lessen monocultural crop production. Yet the Tongan situation is unusual in the Pacific in that farmers hold individual tenure to single clearly demarcated fields, situated, on the main island of Tongatapu, in a favourable agricultural environment of mostly flat land with good volcanic soils. In more vulnerable areas of sloping land or poor soil, the protective and enhancing qualities of trees become more significant. Also, Pacific Island agroforestry systems have developed in a milieu where the unit of management was not a single field but a block of communal land wherein individuals held temporary tenure to various bits of garden land and enjoyed usufruct rights of varying sorts to trees, groves, and forest. This evershifting pattern of use amid a great diversity of arboreal and annual plants is antithetical to agronomic assessments of yield and economic efficiency. As Budowski (1982, 14) noted, comparisons of monocultures with agroforestry systems "may by no means be easy," especially as such evaluation is complicated by various short- and long-term economic projections concerning, for instance, the value of wood or the present and future estimations of environmental damage (for instance, erosion, use of pesticides in monocultures) and, even more so, by the appraisal of social and cultural factors, themselves complicated by a dynamic evolution in time that is difficult to foresee.
Because institutional agroforesters, agronomists, and development agents are generally preoccupied with commodity production and maximization of yields, they seem at times almost to suffer from a sort of paralysis in the face of the difficulties or impossibility of producing quantitative assessments of agroforestry systems, especially ones as complex and unbounded as those developed indigenously in the Pacific Islands. What is called for as interest shifts to "sustainable development" is new ways of evaluation that integrate protective and productive functions, and new land-use institutions that focus on optimization of the whole landscape rather than component maximization aims. Lundgren (1987) has put forth a similar line of argument, but, no more than he could, can we suggest an "ideal" structure and set of objectives for tomorrow's land-use-related institutions. We will, however, end with a few recommendations on how further to encourage agroforestry in the Pacific Islands.
Existing systems as prototypes for development
Pre-packaged agroforestry technologies are by their nature alien, and their introduction is usually part of a short-term project, often set off from the general pattern of life and economy. When the project staff depart, the project often falls apart. Yet within the population already practicing indigenous agroforestry, experimentalists are legion. Pacific Islanders, like people all over the world, are fascinated by plants, like to experiment with them, and will happily carry a young individual plant from island to island or from valley bottom to mountain ridge or vice versa to establish it in a new home. If it works there, it will be reproduced and further disseminated. It makes sense, therefore, that at least some of the attempts at agroforestry intervention concentrate simply on supplying trees as raw materials for distribution. Some of these trees may be traditional, some newly introduced. The experimental work, the hybridization of new species into older systems, will be carried on in the place where it counts for most - among the local population. This does not of course mean that more formal agronomic experimentation is not equally or more valuable in terms of accurate information, but simply that experimenta tion carried on locally in the forests, woodland fallows, gardens, and grasslands is likely to be much more effective in achieving the goal of encouraging agroforestry.
Nurseries already successfully distribute seedlings and cuttings of fruit-trees, timber species, and legume trees in some Pacific Island countries (e.g., in Tonga, as described by Künzel 1989, 47-48), but they could be more comprehensively stocked and could incorporate extension work on agroforestry more strongly. Such nurseries would provide a central, permanent focus for agroforestry development.
Few Pacific Island countries would be able to establish an "agroforestry unit" on a permanent basis. If they were, the unit might better be placed in the Department of Agriculture rather than the Department of Forestry. In place of such an intersectoral unit, extension workers could at least be better educated in agroforestry and in ideas about the broad integration of protection and production. They could, for instance, stress the values of durable living fences or hedges; promote traditional techniques of mulching, composting, or improved fallow; and encourage agroforested home gardens and polycultural orchards.
As with extension education, so too could agroforestry be promoted and publicized by other forms of education. Multimedia public programmes could be developed, in the vernacular, to stress the long-term value of existing agroforestry systems and the dangers of deforestation and agrodeforestation. Radio programmes along these lines already exist, as in Vanuatu, where the Environment Section has a weekly broadcast. Agroforestry can be better introduced, with appropriate field activities, into school curricula in both urban and rural areas. The nutritional value of tree foods can be incorporated into formal education or, for instance, into child-care information, as has been done by Fiji's National Food and Nutrition Committee.
Environmental impact assessment
When forests and woodlands are to be cleared, EIA generally includes a consideration of consequences with regard to erosion or hydrology, but the lost value of food and other products from trees also needs to be part of the formal assessment procedure. That this value often exceeds the value of the timber has been clearly demonstrated elsewhere in the world.
Although long-term intensification can be seen as destructive of forests, intensification of annual production, often through the use of agroforestry techniques (Raintree and Warner 1986), lessens the extension of agriculture in the short term. Experience has shown, in Java, for instance, that severe agricultural intensification leads to a highly intensive, though spatially restricted, agroforestry. Inducing farmers to intensify is another matter, for it generally requires greater inputs, in some form such as capital, labour, fertilizers, management skills, and so forth. Appropriate consideration of the effects on the whole landscape of the intensification of certain kinds of production from land again requires that sectoral compartmentalization be lessened.
Further research and documentation of indigenous systems
Individual countries need to establish intersectoral committees or working groups to compile and publish lists and descriptions of useful tree species that should be protected or promoted locally. Further research is required into the existing systems, their component trees, the associated technologies, the methods of establishment, and the quantity and value of the products.
This book's descriptions of indigenous Pacific Island agroforestry systems may at times have seemed excessively detailed, but the book's coverage of the topic remains far from complete. What has been described, however, is sufficient to establish that traditional and existing agroforestry systems and their component trees have played and could continue to play a significant role in the provision of useful materials, in the enhancement of productivity and diversity, and in the stability of agro-ecosystems in the Pacific Islands. Recognition of agroforestry's multiple values and further documentation of indigenous systems can contribute to the effort to stem agrodeforestation and to stimulate the future flowering of Pacific Island agroforestry on the basis of the rich indigenous resource that has already for so long successfully blended production with protection.