The Environmental History of Africa

Topic 13 - Big Bang in the Upper Guinea Forest, 1500-1900

  1. Ecosystem change sometimes takes place on the basis of existing features but with changes in climate or changes in human action, but is local. This story of the transformation of West African forest illustrates a different set of actions.

  2. The Upper Guinea forest is one of two large rainforest systems in African (Congolian) divided by Dahomey gap.
    1. Upper Guinea forest is worlds least biodiverse system because of wide historical fluctuations of wet/dry. Forest species are adaptations of savanna varieties rather than other way around. Only a small core of permanent forest ecozone exists in SW Ghana. Hemmed in by savanna and coastal plain and the associated trade and political networks. Beginning in 17th c. many powerful state systems emerged in this zone. Why and how did they function?
    2. Forest ecosystem is based within moist climate and the competition over sunlight and soil nutrients. The succession of plant life is a function of access to sun and the ability to exploit shallow soils. Humus destroyed by temperature so only top soil levels have fertility. Leaf fall cycle creates fertility but not easily exploited for agriculture. Thus fundamental human problem has been sources of carbohydrates to support dense settlement (protein more widely available). Wild corms and yam not productive and insufficient. Kola nuts provided trade link and value to family labor to collect. So how did states develop based on dense human population.

  3. Big Bang theory of Ivor Wilks began by calculating the amount of primary forest that had to be removed to begin an agricultural settlement and sustain a single farm.
    1. Key fact is that first settlement of a farm in the forest required removal of 1250 tons per acre of trees, underbrush, and other primary forest vegetation. Labor and technology levels make problem seem insurmountable. Use of fire, iron tools but mainly human labor. Task was arduous and dangerous.
    2. Key is that once initial clearing made then after 15 years fallow only 100 tons of secondary vegetation needed removal. So it was the initial push to clear that was key. How and when did this take place?
    3. External factor of the Atlantic opening post-1500 brought trade stimulation. Initially Europeans brought slaves for gold. Akan social systems encouraged new members as slaves, fictive kin, and dependants. Slave trade provided economic growth and access to prestige goods and firearms. Firearms allowed expansion from forest zone onto savanna where wars of expansion channeled captives into forest as labor to provide first clearing and maintenance.
    4. Elaboration of "forest fallow" system that involved rotation of plots, opening of frontier lands and social systems of domination that controlled labor and organized statecraft.

  4. But how did this system in the forest overcome the problem of food supply. African food systems of tubers (yams and wild corms) and cereals (sorghums, rice, and millets) had problems supporting dense populations because of climate, productivity, etc.
    1. Links to Atlantic system provided two critical new sources of food. Early slave traders brought new foods from New World ecosystems that thrived in African environment: maize and cassava (manioc) adapted perfectly to needs of human pop. and requirements of forest ecology. Maize was quick food after first clearing. Cassava thrives in nutrient poor soils and was low labor. Boost in forest food supply allowed development of food ways that supported state and later became Africa as a whole's primary food sources. Later cocoa was added to mix as additional New World crop that used forest ecology and expanded human settlement.
    2. But unintended consequences were creation of new malaria zone by clearing and addition of humans gave habitat to anopheles gambiae mosquitoes and new human hosts for malaria. Changing ecology of forest with cocoa, oil palm plantations, and forest fallow plots change distribution of mammalian life (bush meat). Lumbering is an issue. Miscalculation of forest off-take and measuring of forest land in colonial period may have created exaggerated estimates of forest loss.