Food Production in the Forest Zone of West Africa: Archaeological and Historical Perspectives
Abstract and Keywords
Recent narratives on the origin of food production in the West African forest zone have replaced earlier diffusion-based models with viewpoints that emphasize the diversity of sources for plants and animals exploited and domesticated in the region. Management of indigenous tree species, including oil palm and incense tree, managed first by indigenous foragers, have the longest history in the area, dating back to over 8,400 before present (bp). After the 4th millennium bp, domesticates such as pearl millet, cowpea, and domestic caprines were introduced from adjacent Sahel and the savanna regions, and populations began to favor oil palm over incense tree. The mechanisms of these introductions are less clear but likely involved both diffusion and/or movements of peoples who became sedentary to varying degrees. Palaeoenvironment is an important factor to consider in tracking the development of food production in the forest zone; however, some combination of natural and human-mediated changes took place, the nature of which was not uniformly distributed.
Approaches to the Study of Forest Zone Food Production
Diffusionist views1 characterized many explanations offered for major human developments (food production, urbanization, trade, and technology) on the African continent for much of the 20th century.2 For example, the origins and domestication of many crops, animals, and developmental trajectories of food-producing systems in sub-Saharan Africa were explained in terms of outside influences emanating from the Levant through northern Africa.3 However, an appraisal of relevant data,4 particularly from recent archaeobotanical and zooarchaeological research,5 has demonstrated that perspectives are changing, and more nuanced explanations are being offered for the origins and development of food production in Africa. It has been suggested that a variety of ecological and technological factors acting at the regional, sub-regional, and local levels led to the emergence and development of diverse indigenous food-producing systems in different parts of the continent, accompanied in some areas by the diffusion of Near Eastern, African, and later New World domesticates.6 In West Africa, direct archaeological evidence for food production is becoming increasingly available; however, some gaps remain, particularly for the forest zone.7 As a result, the current state of knowledge of the transition from foraging to farming in the West African forest zone is limited for the most part.
The term “food production” in archaeology is bedeviled with scholarly debates hinging upon the appropriateness of its application. Archaeologists have not been able to unanimously agree on which activities, skill, or set of skills of the food quest (hunting-gathering, tending, cultivation, and domestication) should be regarded as food production.8 The aim of this article is to consider the skills and knowledge humans have employed in obtaining food in the forest zone of West Africa. We examine food production here in terms of human interaction with plants and animals, captured by the term cultivation and not in terms of morphological characteristics, as is the case with debates on the origins of domestication or agriculture. This examination requires an understanding, first of the environment of West Africa, because this is a crucially important factor in determining the emergence and development of food production in the region and beyond.9
West Africa: Geography and Environment
West Africa is one of the six main geographical regions of the African continent. The region has its southern and western margins bordered by the Atlantic Ocean, the east by the Cameroon-Adamawa highlands, and the north by the Sahara Desert. The region comprises 18 countries (including Cape Verde) spread over an area of about 6.2 million square kilometers (Figure 1). The landscape is a vast low-lying tableland comprising plateaus and drainages, with a narrow coastal plain and continental shelf.10 The relief comprises the lowlands, which lie approximately 305 m above sea level; the interior plains, which constitute most of West Africa; and the highlands. The most important river in West Africa is the Niger, which is about 4,180 km long with two major tributaries, the Benue and Bani Rivers. Temperatures in West Africa are high throughout the year, with variations in the different climatic zones. Rainfall is seasonal, and at the coast, there is heavy rainfall of over 2,000 mm per year, covering a period of nine months. Moving away from the coast, the amount and duration of rainfall decreases significantly, causing a northward decrease in the forest vegetation and eventually into different categories of savanna woodlands, and finally the desert. The West African savanna is divided into the Guinea, Sudan, and Sahel, based on a west-to-east zonation of rainfall and vegetation belts. The forest zone encompasses all of Sierra Leone, Liberia, a substantial part of Guinea, and southern portions of Nigeria, Côte d’Ivoire, Togo, Guinea-Bissau, and Ghana. The Dahomey Gap divides the West African forest zone into two—the western forest zone also called the Upper Guinea Forest, which stretches from Guinea to western Togo, and the eastern forest zone also called the Upper Guinea Forest, stretching from southeastern Benin through southern Nigeria into Cameroon.11 The forest zone has generally high temperatures throughout the year with maximum of about 31ºC and minimum of about 21ºC because of its location near the equator. The forest zone is rich in humus that arises from heavy leaf fall, but soils tend to be severely leached because of high rainfall.
Food Production in the West African Forest Zone: Historical Perspectives
Early attempts at explaining the origins and development of food producing systems in West Africa and the relationships amongst these systems across ecological zones have focused on diffusion or migration of peoples from the Near East through the Sahara into the West African forests.12 This idea implies that early West African peoples were not producing their own food; instead, it was assumed that they continued hunting and gathering until groups from the Sahara brought them the knowledge of food production. It was assumed the movements were caused by fluctuations in climatic conditions during the Holocene, which affected human life in Africa, resulting in migrations and southward movement of people from the Sahara.13 It is suggested that there were changes in rainfall regimes in the Sahara, which at 6,500 before present (bp) became a function of the Inter-tropical Convergence Zone (ITCZ). This resulted in a humid period between 6,500 and 4,500 bp because of a northward shift of the ITCZ.14 This evidence appears to be supported by data from Lake Chad, which show that the current ITCZ has been in existence since about 7000 bp. It also suggests that after 4500 bp, the ICTZ shifted southward leading to drier conditions and the disappearance of lakes in the southern Sahara. These drier conditions forced agro-pastoralists occupying the Sahara to migrate to the south.15
A question has been raised as to why the southern portion of West Africa was not occupied by pastoralists before the arid period, and the answer may be that the south was not conducive to herding because of the presence of tsetse fly.16 The tsetse fly thrives in areas with a minimum annual rainfall of 500 mm, and as such the amount of rainfall in the Sahara between 6500 and 4500 bp was too little to be conducive for the tsetse fly. Thus, a southward movement of the ITCZ resulted in a corresponding shift in the habitat of the tsetse fly, thereby allowing pastoralists to move south bringing with them the knowledge of food production.17 Although the knowledge of food production reached the Sahel and Sudan regions of West Africa via stimulus diffusion, the West African tropical forest was not penetrated until iron working technology diffused from North Africa into Sahelian West Africa. It was only then that food production was possible in the West African forest zone. It was believed that West African forests “remained the home of primitive hunters until quite recently.”18 Three factors hindered the spread of food production to the forest zone: poor forest soils that become infertile after a few crop cycles; inability or difficulty using stone tools to clear the forest for agriculture; and low yields of pearl millet (Pennisetum glaucum) and sorghum (Sorghum bicolor), which were the main crops of the Sahel and Sudan zones.19
Others have argued that communities in the West African forest zone were engaged in food production long before the introduction of iron. By 2800 bp, farming techniques in the yam (Dioscorea cayenensis, D. rotundata) and oil palm (Elaeis guineensis) belts of Nigeria and other forest regions of West Africa may have involved anthropogenic clearance of woodlands20 using flint axes such as the Neolithic-type axes found in Ghana.21 The nature of vegetation in the forest zone, as derived from palynological studies in the Niger Delta, indicate that before 3500 bp and just before 2800 bp, oil palm constituted an insignificant forest species. However, oil palm pollen increased significantly after 2800 bp with a corresponding decline in forest species and the appearance of weeds associated with cultivated or refuse areas.22 This rise in oil palm pollen and the corresponding decrease in forest species combined with the appearance of weed species of cultivated lands has been argued to constitute evidence of human cultivation in the forest zone at about 2800 bp. This correlation was made because oil palm is a heliotropic pioneer species known to thrive on the fringes of forests or secondary forests, and river valleys. It tends to be shade-intolerant, requiring sufficient sunlight, which is normally absent in the dense forest. As such, human clearance for cultivation most likely provided the conditions for the spread of oil palm, which has been proposed to be an index of cultivation.23
Palynologists have argued against the postulation that the abundance of oil palm after 2800 bp can be viewed as an index of cultivation. They propose instead that the increase in oil palm pollen was the result of aridification, which forced the forest to retreat and allowed oil palm to flourish.24 Moreover, analysis of sediment cores from Lac Sélé in southern Benin25 demonstrate that sudden drier conditions occurred in the area by 4500–3400 bp, which was concurrent with the formation of the Dahomey Gap and the disappearance of the rain forest in that area. Following this, there was a return to more humid conditions between 3300 and 1100 bp that resulted in forest regrowth, consisting of a high percentage of pioneer species among which oil palm was prominent. It has been argued that the return to humid conditions resulted in the flourishing of oil palm and other pioneer species, and human agency was not involved.26 Others have questioned the ability of the West African pollen record to disentangle human from climatic factors in the spread of oil palm, and have argued instead that the macro-botanical record preserved on archaeological sites is a more direct indicator of human-oil palm interaction.27 Anthropogenic activities may have taken place but without necessarily leaving a signal that can be read in pollen diagrams. There is also the possibility that both climate and humans may have been responsible in ways not readily discernible at present.28
On the whole, years of accumulated data from archaeological, ecological, and ethno-archaeological studies are revealing that West African groups were involved in independent food production at different levels in varying ecological zones.29 Given this observation, it has been suggested that the trajectory of economic change over the last 10,000 years in West Africa has been different from that observed elsewhere on the continent, where animal herding was practiced before crop husbandry and crops were domesticated as late as 5,000 years ago.30 In recognition of the apparent centrality of ecological factors in studies of food production, some scholars31 recommend a critical examination of how African domesticates were derived from their wild progenitors in various ecological settings. Ecological studies indicate that livestock domestication most likely started in the semi-arid tropical and subtropical savannas of Africa. This may be explained as a result of a high soil pH (+7.0) in these regions, which means that macro elements such as nitrogen and phosphorus become readily absorbable by plants, resulting in pasturelands that are rich in protein content. This is in contrast to humid tropical zones where soil pH and rate of absorption of macro nutrients is low.32 In addition, a number of factors can influence pastoral land use, including rainfall, soil types, species palatability, nutritional value, insects, and disease. Soils that allow for easy exchange of cations are conducive for the growth of good pasture. An effective cation exchange enhances the availability of trace element needs of plants, and the reverse situation deprives plants of these crucial elements. Therefore, a combination of high cation exchange and the presence of nutrients in the soil allow for the survival of large herbivores, and semi-arid environments are optimal for these conditions.33
In terms of cultivated plants, some researchers34 have posited that West Africans exploited indigenous crops that were well adapted to conditions of high temperatures and humidity. These conditions are also conducive for the breeding of pathogens that most crops from other parts of the world cannot tolerate. Given the differences in environmental conditions, it has been argued that a diverse array of crops including yams, fonio (Digitaria exilis), cowpea (Vigna unguiculata), rice (Oryza glaberrima), pearl millet, Kersting’s ground nut (Macrotyloma geocarpum), kola nut (Cola acuminata, C. nitida), and oil palm have their origins in the West African forest zones and have been cultivated in the region for a very long time.35 To date, archaeo-botanical evidence has supported the early domestication of cowpea,36 pearl millet,37 and possible management of oil palm and incense tree (Canarium schweinfurthii).38
Five traditional food-producing systems have been described for West Africa: cattle (Bos taurus) herding north and east of the Sahara; seed-crop systems on the slopes and scarps of highlands in the central Sahara; seed-crop systems in parts of the Sahel and northern savanna zones; mixed farming and cattle rearing in the eastern and central Sahel and some parts of the northern savanna; and root and tree-crop systems in forest zones.39 Recent biogeographical studies of crop origins have shown evidence of twenty-four likely localities of independent crop domestication in the world, and five of these are in Africa. These studies have revealed that, in the West African forest zone, crops such as yam and related species, Hausa potato (Solenostemon rotundifolius), oil palm, kaffir potato (Plectranthus esculentus), and kola nut were independently domesticated in the region.40
It is important to note that, although early African farmers independently domesticated and cultivated plant foods, they also skillfully integrated introduced crops into indigenous farming systems and in some circumstances resisted the spread of new crops. Ethiopian farmers, for example incorporated indigenous African species and crops imported from the Near East and New World, into a highly integrated cropping system.41 In West Africa, maize (Zea mays), a New World domesticate, arrived shortly after the 16th century and has been viewed as a blessing in some areas, but not everywhere. It was accepted based on cultural, political, and ecological conditions in different regions.42 For example, the Benin Kingdom, the historical kingdom of Dahomey, Ghana (Gold Coast), and Côte d’Ivoire, readily integrated maize into existing farming systems. However, in Guinea, Sierra-Leone, Senegal, and The Gambia, the level of acceptance was not high, possibly because of the abundance of African rice varieties endemic to these areas. Maize cultivation, along with other New World crops, may have added to the human motivation to transform the forest zone in Upper Guinea that extends from Sierra-Leone through to Ghana and the Dahomey Gap into Nigeria.The kingdoms that thrived in those forest regions accepted maize because it provided caloric bases for their armies, bureaucracies, and populations far better than forest tubers.
Archaeological Perspectives on Food Production in the West African Forest Zone
Much of the West African forest region remains unstudied archaeologically,43 with the possible exception of parts of Ghana and Nigeria.44 Within this broad region, archaeological, data are especially lacking on the transition to food production. This unfortunate state of research, coupled with an absence of human remains and the uncertain status of the West African Stone Age,45 has limited our understanding of prehistoric subsistence and food history of the forest zone. Perhaps previous assumptions that forest zones were not inhabited or exploited until the introduction of iron tools46 is partly responsible for the paucity of archaeological research in this area. In contrast, over the past two decades, there has been an upsurge in interest by archaeologists, but most investigated sites are from the Sudan or Sahel regions.47 With the exception of the Kintampo Tradition,48 very few forest zone sites have been investigated.
Recent archaeological data indicate that populations in Africa exploited and continue to exploit both wild and domesticated plants and animals at varying degrees from region to region.49 This pattern has been observed at some investigated sites in the West African forest zone, and this article focuses on the Kintampo and other Holocene forest zone archaeological sites that have produced significant evidence relating to early food production.
Forest Zone Sites
Bosumpra Cave is located on the Kwahu Plateau, which is part of the eastern section of the Ashanti uplands in Abetifi town, southern Ghana.50 The site is situated in the deciduous and semi-deciduous wet-forest zone and covers an area of about 240 m² at an elevation of about 613 m above sea level. Bosumpra was first excavated in the 1940s when the site yielded Later Stone Age (LSA) microlithic tools and a small amount of pottery. The occupational sequence was divided into a long prehistoric and historic pre-Akan and Akan occupations. A second series of excavations at Bosumpra was completed in 1974.51 Radiocarbon dates from excavations undertaken in 2008–2010 range from 10,280 ± 70 bp to 365 ± 35 bp.52 Bosumpra deposits have produced the longest occupational sequence in West Africa for which macro-botanical studies have been completed. It is a unique site producing a 10,000 year record of plant use in the forest zone. Large quantities of macro-botanical remains were recovered, including oil palm, incense tree, pearl millet, cowpea, and seeds of wild plants, including Bergia sp., Cleome, sp., and Zaleya pentandra. The ubiquity of remains of oil palm and incense tree at Bosumpra may be regarded as evidence of early use of these plants for food by forager groups occupying the site, possibly in an arboricultural system.53 Quantitative analyses of macro-botanical evidence from Bosumpra54 supported earlier observations55 that incense tree dominated early Holocene deposits and reflects forager subsistence. In the later Holocene, oil palm assumed dominance in the archaeological record, and the nature and concentration of the oil palm remains may constitute evidence for management to obtain higher yields by more sedentary groups. This suggests that humans were already managing plants for food in the forest region of West Africa as far back as the Early Holocene. Oil palm shells at Bosumpra were directly dated to 8410 bp, representing the earliest directly dated evidence for its utilization in West Africa.56
Domesticated pearl millet and cowpea from Bosumpra represent the first evidence of these crops in the southern forested region of Ghana towards the end of the LSA. Radiocarbon dates suggest that cowpea was utilized in the 4th millennium bp, while pearl millet appeared later in the 3rd millennium bp.57 The presence of arid-adapted crops such as pearl millet and cowpea in the southern forest region of Ghana may add credence to the idea that the crops spread from north to south as inferred from the Kintampo sites of Birimi and the B-sites.58 The movement of pearl millet southward to the Central African rainforest of Cameroon took place by 2500 bp, possibly the result of the development of cultivars adapted to humid conditions or climatic change involving increased seasonality in the region.59
Iwo-Eleru Cave is located 24 km east of Akure, the capital of Ondo State, southwestern Nigeria. The name in Yoruba language means “cave of ashes” because of the apparent ash concentrations characterizing the site deposits. The cave is found in the forest zone, and the locality experiences a mean annual rainfall of about 1400 mm. It was initially excavated in 1965.60 Excavation revealed a long series of occupations took place in the cave, spanning the LSA and Iron Age. The project was aimed at determining the nature of LSA populations occupying the rain forest, specifically to assess the assertion by some scholars that the forest was not inhabited prior to the introduction of iron tools.61 Cultural materials from the excavation amounted to well over half a million and included flaked stone artifacts made of quartz and chalcedony, microliths, and a variety of other lithic tools. The excavators62 suggested that the occurrence of gloss-edged trapezoidal microliths indicated cereal harvesting, however, the sheen also could have been formed by their use in harvesting wild grasses. Pottery forms included open bowls and globular vessels of different sizes, decorated with grooves, roulettes, incisions, stamps, and impressions. Human remains were also recovered and yielded a radiocarbon determination of 11,200 ± 200 bp. This date was later supported by a uranium series dating directly on the bones.63
Subsistence remains from Iwo-Eleru are few and, unfortunately, fragments of animal bone recovered were lost before they were analyzed at the University of Ibadan. The presence of a land snail (Archachatina marginata) suggests early exploitation of this species, which is still collected for food in Nigeria today. The shells of this species were recovered from both LSA and Iron Age levels within the rock shelter. Two additional species, the land snail (Limicolaria aurora), and freshwater species (Potadoma morchii) were found in abundance outside the shelter but were absent from the excavation units. As such, their role in subsistence is unclear. Unfortunately, no macro-botanical samples were collected for analysis, and soil samples examined for pollen yielded no specimens, possibly the result of poor preservation.64 On the whole, data from the rock shelter, although limited in terms of reconstructing subsistence, have clearly demonstrated that humans inhabited the forest zone by the terminal Pleistocene. Future investigations should concentrate on elaborating this preliminary subsistence evidence from Iwo-Eleru.
The Apa Locality
The Apa Locality is situated in the thick swamp and rain forest zone, about 7 km west of Badagry, southwestern Nigeria. It was excavated between 1993 and 1995, with the aim of determining the nature of forest zone LSA populations and their subsistence.65 Two sections of the site were excavated and designated Apa1 and Apa2. Ap1 was discovered by construction workers who exposed an occupation level represented by a layer of charcoal and potsherds at a depth of about 1.5 m from the surface. A test pit of 3 x 1 m was excavated quite rapidly to save the site from destruction. Given the lack of time, a larger unit could not be opened because of dense vegetation covering the area. Material remains recovered included charcoal, potsherds, charred palm kernels, and a ground stone axe. A radiocarbon date on charcoal from 1.75 m below surface produced a determination of 2670 ± 90 bp.
Ap2 was located through information provided from the King, Oba Adeniran Adewoga. The site was a mound located about 60 m southwest of the king’s palace. There were no surface finds on the mound, but residents stated that cultural materials were removed from the surface over time by farming activities. A test pit of 2 x 1 m was placed atop the mound, which was excavated down to sterile soil. Nine stratigraphic layers were identified, and recovered materials included an upper grinding stone, palm kernels, animal bone, horn, snail shells, fragments of smoking pipe, metal fragments, white glass, broken bottles, and beads. A radiocarbon date of 360 ± 50 bp was obtained from a charcoal sample recovered at the depth of 1.58 m.66
The results from Ap1 and Ap2 demonstrate that the forest zone of southwestern Nigeria was inhabited during the LSA (2670 ± 90 bp) and historic periods (360 ± 50 bp). Recovered subsistence data suggest both phases of the site occupation were characterized by the use of oil palm for food; unfortunately, the faunal remains, including bone and shell, have not been identified. Although tentative inferences were drawn about ancient subsistence, much work on this aspect remains to be completed.
Kintampo Tradition Sites
Kintampo sites are found throughout the forest and savanna regions of Ghana and parts of Côte d’Ivoire and Togo, but most are located in central Ghana. The name Kintampo is derived from the Kintampo District of Brong-Ahafo region and is used to describe a group of archaeological sites that share similar material culture. The Kintampo is the best defined archaeological tradition in West Africa, typified by artefacts including comb-stamped ceramics, grinding stones, terracotta cigars (oblong-shaped objects scored on both sides, with unknown function), burned daub, polished stone axes, adze blades, and arm bands. It is a ceramic LSA cultural tradition that thrived in the 4th millennium bp and has been linked to the origins of food production in sub-Saharan West Africa.67
Earlier explanations of the origins of West African food production were linked to environmental changes that forced populations from Saharan North Africa into West Africa.68 As stated above, these theories were supported by palaeo-climatic evidence demonstrating a period of desiccation in the Sahara at about 4500–3200 bp, which did not affect the west and central parts of the continent until later. This idea was supported by the observation that radiocarbon dating of sites with evidence for food production tended to produce later dates southwards from the Sahara.69 This model became the main explanation for origins of food production at Kintampo sites. It was claimed that either food producing populations moved away from the Sahara and replaced existing Sahelian groups, or food production spread through stimulus diffusion.70 In recent decades, some have argued that data from Kintampo sites, which are found in several ecological zones, indicates that regional resource specializations existing today may have existed during the Kintampo period.71
Food production among Kintampo populations has been seen as an amalgam of northern savanna and indigenous forest zone foodways. It was posited that groups in the forest zone were exploiting yams, oil palm, incense tree, and hackberry (Celtis sp.), while in the savanna, people were cultivating pearl millet.72 Recent work has demonstrated that, by the third millennium bp, Kintampo peoples practiced a broad range of subsistence activities that crosscut savanna and forest regions. Agro-pastoral Kintampo groups were in possession of domesticated species including pearl millet,73 cowpea,74 an ancestor of N’dama cattle (Bos taurus) and caprines (Caprinae).75 They also may have practiced some form of arboriculture of oil palm76.
K1 and K6
Excavation of Kintampo sites began in the 1960s.77 During these and following investigations, rock shelters K1 and K6 were found to produce significant cultural and subsistence data.78 Cultural materials recovered were not just of the Kintampo, but also of another group known as the “Punpun Tradition.” The Punpun is poorly understood, but believed to be an LSA ceramic tradition of hunter-gatherers associated with rock shelters on the hills surrounding the modern village of Kintampo in central Ghana. Radiocarbon dates for the Punpun have fallen within the same range as the Kintampo.79
The rock shelter K6 is located in semi-deciduous forest about 5 km from the village of Kintampo. The 1982 excavations produced macro-botanical remains along with abundant snail shells, animal bones, ceramics, polished stone tools, terracotta cigars, beads, and burned daub. Recovered animal remains included domesticated cattle and caprines, with a high diversity of wild species including forest buffalo (Syncerus caffer), vervet monkey (Chlorocebus pygerthrus), baboon (Papio sp.), giant rat (Cricetomys sp.), cane rat (Thryonomys swinderianus), tortoise (Kinixys sp.), fresh water turtle (Pelomedusa sp.), monitor lizard (Varanus sp.), shrew (Crocidura sp.), and Guinea fowl (Numida meleagris). Botanical evidence included oil palm shells, which were found in all Punpun and Kintampo contexts, incense tree, and hackberry. In addition, seeds of the bean family (Fabaceae) were recovered, which may represent cowpea.80.
Prior to the 1982 excavations of K6, earlier research in the rock shelter identified a transition zone from Punpun to Kintampo based on stylistic and technological differences that were attributed to changes in subsistence strategy.81 The 1982 excavation revealed basically the same trend with evidence that cultural materials of the two traditions were mixed in some deposits.82 Punpun subsistence was based on oil palm, incense tree, and wild plants and animals from various habitats, while the Kintampo comprised both wild and possibly domesticated animals and plants. It was demonstrated that the K6 faunal assemblage consisted of more wild than domestic animals, suggesting that Kintampo people practiced a mixed economy.
On the whole, data from 1982 excavations at K6s called into question the assertion by earlier scholars that the Kintampo was the result of migrants moving into the area from the north who were escaping increased aridification of the Sahara.83 The overlap of Punpun and Kintampo may constitute evidence for a gradual transition from Punpun to Kintampo,84 in contrast to previous work that argued for the replacement of the Punpun by the Kintampo.85 The observed differences between the two traditions may be the result of varying strategies used for obtaining food and other necessities of life.86 It is possible, however, that cultural contacts may have resulted in the diffusion of some traits, such as pearl millet, to local populations of central Ghana.87
The B-sites are composed of several rock shelters bearing the remains of Punpun and Kintampo traditions, excavated under the auspices of the Kintampo Archaeological Project (KARP). The project began in 1998 with the aim to examine the relationships between the Punpun and Kintampo of central Ghana, and the origins of the Kintampo.88 The KARP team investigated six rock shelters located about 27 km southwest of the present village of Kintampo and 2 km south of rock shelter K6, previously excavated in the early 1980s.89 All six rock shelters are located in a semi-deciduous forest/savanna-forest environment similar to K1 and K6. The series of shelters were named the B-sites after a local hamlet of Boase, a name that, when translated, means “under the rocks.”90
Excavations revealed two phases of occupation by the Punpun and Kintampo: an Early Phase (3850–3550 bp) and Late Phase (3550–3350 bp). Kintampo materials were found in large quantities at all six sites but only three produced Punpun pottery. Evidence of purely Punpun deposits did not come to light at the B-sites. Excavated assemblages from two of the rock shelters revealed that Kintampo pottery, with its associated material culture, increased with time, while those of the Punpun remained at a constant 5%. These most recent excavations at the B-sites91 support a previous interpretation92 that the Punpun were replaced by agro-pastoralists escaping from increased aridity in the Sahara, leading to the development of the Kintampo tradition. These conclusions contrasted with results of excavations completed in the early 1980s93 which considered the Kintampo to be a largely indigenous cultural development.
The macro-botanical remains of the B-sites included incense tree, cowpea, a single grain of pearl millet, and oil palm shell, the latter of which dominated site assemblages.94 Substantial variation was identified in shell size and thickness, and it was observed that groups may have used several varieties of oil palm. The high level of fragmentation observed in the shells, which presented challenges in identification, was attributed to thorough processing for oil, and a similar pattern was observed in the remains of incense tree. Apart from providing oil, the kernels of incense tree can be cooked and eaten, and high concentrations of these tree fruits in the B-sites deposits may suggest intensive use or arboricultural management. The B-sites cowpea and pearl millet represent the only domesticates identified and their presence in small numbers in this forest zone context may indicate that pearl millet was brought in from the Sahel via trade or it may have been grown locally on a small scale. (The domesticated cowpea, if considered along with possible cowpea from K6, may have constituted a more significant part of the diet and may have been cultivated. Charcoal is present but generally decreases as oil palm endocarps increase suggesting that endocarps may have been used as fuel in place of charcoal.95
Zooarchaeological remains included large bovid teeth and a cranial fragment of a large mammal, most likely from the same individual. There was also a fragmentary mandible that was assigned to Bos sp. but was shown to be intrusive.96
Birimi is the northern-most Kintampo site, located on the Gambaga Escarpment in dry woodland savanna of northern Ghana. It is about 7 km northeast of the town of Gambaga in a secured forest reserve under the care of the Ghana Forestry Service. The site extends about one kilometer on two sides of a gully possibly created by an ancient stream. The site was first located in 198797 and was excavated between 1996 and 1998.98 Although Birimi is not located in the forest zone, it is briefly included here to demonstrate the diversity in Kintampo subsistence.
Macro-botanical remains from Birimi were dominated by pearl millet. In addition, small quantities of wild grass grains were recovered, such as Dactyloctenium aegyptium, Digitaria sp., Paniceae, and Poaceae, and seeds belonging to the Fabaceae, Mimosaceae, and Solanaceae. The Birimi pearl millet is small grained compared to modern varieties, and this may indicate that changes in grain shape took place first during domestication with delayed increases in grain size. The high concentration of grains in Birimi deposits and the absence of weed seeds suggest that pearl millet was grown and harvested in relatively pure stands. It is drought tolerant and would have been a suitable crop in the seasonal wet/dry climate of the West African savannas.99 Although pearl millet was likely domesticated in the western Sahel, and the earliest archaeological finds occur in that region during the 4th millennium bp,100 the Birimi specimens represent the earliest evidence for the southward movement of pearl millet, which seems to have reached the semi-deciduous forests of Bosumpa by the 3rd millennium bp and the Cameroonian forest by 2400 bp.101 Pearl millet may have reached the forest zone after the development of humid-tolerant cultivars via human migrants, by diffusion, or its distribution was extended because of climate change.102
Discussion: Early Food Production in the West African Forest Zone
Considering the vast area covered by the West African forest zone, it is unfortunate that a relatively small number of sites has been investigated to date, most of them in Ghana or Nigeria. In terms of investigation of early food production, no site in Nigeria has been investigated in significant detail for subsistence reconstruction. With a few notable exceptions, excavations of Nigerian Holocene sites appear to have suffered from insufficient attention to questions relating to subsistence and early food production.103 In Ghana, the situation is quite different as investigation of subsistence practices of savanna and forest inhabitants has been considered crucially important in answering key research questions, especially regarding the relationship between the Kintampo and Punpun.104 Clearly more investigation is needed of West African forest zone sites beyond Ghana.
Studies of early food production in the forest zone have also been plagued by problems of species identification, in particular of animal remains. For example, investigators at K6 have had difficulty distinguishing zooarchaeological remains of domesticated cattle from African buffalo.105 In the end, bovine remains from K6 were tentatively assigned to the phalanx of domesticated cattle, subject to future scrutiny.106 Another problematic identification was an immature guinea fowl bone—it was difficult to conclude whether it was of a domesticated or wild species. The only unequivocal domestic faunal remains from K6 are those identified as domestic caprines.107 This means that among all the 16 species of faunal recovered from K6, only one is clearly a domesticated species.108
Despite this patchy coverage, we can point to an emerging picture of the history of food production in the forest zone. At present, we know that human occupation of the forest zone extends beyond 10,000 years.109 In the early Holocene, foragers occupying this region used incense tree and oil palm fruits for food and may have managed these trees in an arboricultural system, in addition to utilizing a variety of wild plants and animals. This early management system may have foreshadowed later medieval period agroforestry systems documented in Burkina Faso.110 Later on, incense tree appears to be replaced by oil palm as a significant resource, and this is accompanied by introduction of arid-adapted species to the forest zone, including pearl millet, cowpea, and cattle/caprines.111 It may be that the decline in incense tree, the rise in oil palm, and appearance of domesticates, reflects the replacement or integration of an older foraging economy based on incense tree, oil palm, and wild resources with an economy of settled farmers who subsisted on a variety of wild and domesticated species as seen at K6, Bosumpra, and the B-sites.112 Given the presence of indigenous forest zone populations based on material culture and exploitation of tree fruits, later introductions of plants and animals were not necessarily accompanied by migrants,113 although others have disputed this idea.114 The presence of stone tools such as grindstones, celts, blades, and trapezoid microliths with sheen at sites in the forest zone has been regarded as evidence of plant processing,115 for forest clearance, harvesting of plants, and leather working.116 However, these postulations need to be considered more carefully in the light of new data from forest zone sites.
Given that humans inhabited the forest zone of West Africa during the Holocene, it is relevant to question if or how they impacted Holocene environments through arboriculture and crop cultivation. To the question of anthropomorphic activity, climatic changes most certainly took place, but given the available pollen together with macro-botanical evidence, humans should not be discounted as active agents in forest clearance activities.117 In addition, modifications in the faunal assemblage at K6 indicate forest clearance and garden hunting practices. Because lower levels of K6 yielded higher numbers of arboreal species than upper levels which produced more rodent remains, it is possible that clearance by humans reduced forest habitats and encouraged colonization of rodents and oil palm. This assertion is supported in part by reduced residential mobility represented by large numbers of burned daub and increased ceramics in the upper levels of K6.118 Considering the arguments involved, climatic changes may have acted in isolation in some areas and in combination with human activities in other regions to bring about the retreat of the forest and the flourishing of oil palm in the West African forest zone. This is based on evidence for human and climatic impacts on Holocene vegetation in the Niger Delta, Lac Sélé, Lake Bosumtwi, and macro-botanical remains recovered from archaeological sites.119 Agents of climate change during this early period, including natural and human-mediated, may not have been uniformly distributed over West African landscapes and may have had highly varied manifestations.
Concluding Remarks: The Need for Further Research in the Forest Zone
Early theories on the origin of food production in the West African tropical forest zone were strongly influenced by what were largely diffusionist viewpoints about cultural developments on the African continent. Recent research has demonstrated that human occupation of tropical forest regions occurred throughout the Holocene. The most ancient plants exploited, oil palm and incense tree, are indigenous to the region and were utilized by the 9th millennium bp, while domesticated crops and caprines appeared in the forest zone by the third to fourth millennium bp. It is unclear whether these domesticates were introduced by migrating people or diffused to the region and accepted by inhabitants. Since Kintampo times, peoples have exploited both domesticated and wild species over highly varied ecological landscapes.
It is evident from the foregoing that research on the origins of food production in the West African forest zone has not been extensive. At the moment, it is possible to sketch out a general history of food production, based on a handful of sites from Ghana and Nigeria; however, other forest regions have remained silent. Although these few investigations have started to reveal the nature of human occupation and Holocene subsistence practices in the West African forest zone, additional excavations are needed for a clearer picture to emerge. Discussions on food production in the region often involve speculation, which may be tested with greater geographical coverage and more thorough archaeological investigation.
Discussion of the Literature
West African archaeology originated within a context of colonial sponsored research.120 Archaeologists of the colonial period were primarily Europeans who, for a variety of reasons, projected a biased view of Africa.121 Milestones in human development were explained in terms of migration or influences coming from non-African external cultures that were assumed to have more advanced technological and cultural accomplishments.122. Given this perception, early food production in West Africa was initially attributed to the infiltration or influence of groups from Saharan North Africa, while the West African forest zone was described by colonial scholars as a region inhabited by “primitive” hunter-gatherers until they received the knowledge of iron working technology from North Africa.123 These scholars claimed that arid conditions characterizing the Holocene forced north African people to move south into sub-Saharan Africa, bringing with them skills in food production. Moreover, ecological conditions in the forest zone were believed to have been inimical to the spread of pastoralism, because the tsetse fly was endemic to the region.124 However, more recent ecological and archaeological studies have demonstrated that the mode of economic transformation in the forest zone was uniquely different from other regions of Africa, mainly because root and tree crops125 were cultivated before the introduction of domesticated livestock.
Early studies126 postulated that indigenous occupants of the forest zone were producing food as early as 2800 bp. It was argued that the preponderance of oil palm pollen, a decrease in forest species, and the appearance of weed pollen associated with cultivated lands are credible evidence of cultivation in the forest zone. Oil palm was used as a proxy for cultivation because it is shade intolerant and a pioneer species that thrives on the fringes of forests or in secondary forests and river valleys. Other scholars127 asserted that flint axes were used at about the same time in clearing the West African forest for farming. Palaeoecologists128 have attributed this increased presence of oil palm pollen in the forest zone to climatic fluctuations that resulted in the burgeoning of oil palm across the landscape. However, they have not been able to present an alternative explanation for the appearance of weeds associated with cultivated lands in the forest zone during the period in question. Meanwhile, some archaeologists129 have questioned the reliability of pollen records in unequivocally differentiating the effects of anthropogenic activities from those of climate on the spread of oil palm in the forest zone. They argue that macro-botanical data are a better indicator of human-mediated environmental change and demonstrate how macro-botanical remains support anthropogenic interpretations in the forest zone of West Africa. Unfortunately, very few studies have been completed on early forest zone food, and almost all were completed in Ghana and Nigeria, with only Ghana witnessing sustained research.130 In Nigeria, forest zone research completed to date has been designed to address questions other than early food production,131 with no deliberate attempts made at collecting macro-botanical data to answer questions relating to agricultural history and foodways.
Several economically significant crops were domesticated in tropical West Africa; however, only limited archaeological research has been carried out on early food production in the forest zone. Two countries have featured prominently in the research on early food production, Ghana and Nigeria. In the case of Nigeria, most research completed to date has accidently stumbled upon evidence for early food production, and many of the samples have been lost. However, original field reports from these projects can be found in the West African Journal of Archaeology (WAJA), the thesis section of the University of Ibadan library, and the University of Ibadan Museum of Anthropology and Archaeology. In Ghana, the situation is better because several projects have been undertaken in which forest zone food production and agricultural history were main research goals. Excavated finds from these projects can be accessed at the Archaeology Museum in the Department of Archaeology and Heritage Studies, University of Ghana. The university library is also a primary source for data on early food production in the forest zone of Ghana, including WAJA volumes. Finally, the Ghana Herbarium of the University of Ghana is another important primary source on this subject.
Other sources of primary data include journals such as Antiquity, Journal of African Archaeology, African Archaeological Review, Vegetation History and Archaeobotany, Quaternary International, Current Anthropology, volumes of the UNESCO General History of Africa, and Annual Review of Anthropology. As research and knowledge on early food production in the forest zone of West Africa expands, hopefully, there will be a corresponding increase in primary sources available on the topic.
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Sowunmi, M. Adebisi. “The Significance of the Oil Palm (Elaeis guineensis Jacq.) in the Late Holocene Environments of West and West Central Africa: A Further Consideration.” Vegetation History and Archaeobotany 8 (1999): 199–210.Find this resource:
Stahl, Ann Brower. “Reinvestigation of Kintampo 6 Rock shelter, Ghana: Implications for the Nature of Culture Change.” African Archaeological Review 3 (1985): 117–150.Find this resource:
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Watson, Derek J. “Within Savanna and Forest: A Review of the Late Stone Age Kintampo Tradition, Ghana, Azania.” Archaeological Research in Africa 45.2 (2010): 141–174.Find this resource:
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