Who deforested Central Africa: Man or climate?

Related Articles

Related Articles

Congo Basin : Wiki Commons

It is a much debated question: why did Central African forests become partially fragmented between 2,500 and 2,000 years ago, leaving room for more open forest landscapes and savannah?

Recently, a publication attempted to explain that it was the farming Bantu peoples who were responsible for this, through the large-scale clearing that they undertook. But several IRD experts and their partners (1) contest this argument in Science magazine. The fragmentation of the Central African forest was the result of drastic climate change.

In fact, during this period a phase of general desiccation spread from the equatorial region right to the edges of the Sahel. Numerous data show that it was only 500 years later, in other words some 2,000 years ago, that Bantu colonisation became widespread. The first Bantu populations therefore merely took advantage of the opening up of the forest to enter these areas and start growing their crops.

Did the first Bantu farmers who colonised the forests of Central Africa 2,500 years ago, also clear the land on a large scale, as was recently put forth? Or did they simply take advantage of a drastic climate change that fragmented the forests and made it easier for them to enter these parts? Several IRD experts and their partners (1), archaeologists, paleo-environmentalists and palynologists (2), defend the climate theory in Science magazine.

A semi-nomadic lifestyle

The ancestors of the Bantu started settling 4,000 years ago from the northern edge of the forest down to the coastal grasslands of Gabon. They practiced pottery and stone polishing, and cleared small parts of the forest fringe for slash-and-burn farming. But there were few of them and their impact was slight. When the major fragmentation of forests started 2,500 years ago, the Bantu had only just learnt to use iron: it was the beginning of the Iron Age.

A boom period for the Bantu


Subscribe to more articles like this by following our Google Discovery feed - Click the follow button on your desktop or the star button on mobile. Subscribe

The concentration and spreading of archaeological records – more than 500 radiocarbon dates established on pottery, stone or iron tools – show that the massive colonisation of the Congo Basin by Bantu farmers started only 2,000 years ago, and that it reached a peak between 1,900 and 1,600 years ago.

At the same time, all the available paleo-environmental data indicate a new phase of forest expansion that also started about 2,000 years ago depending on the regions, proving that growing Bantu settlement did not prevent the vegetation from flourishing. The young civilisation simply took advantage from the opening up of the forest to enter it more easily.

The extent of forests has varied greatly over the past 11,000 years

Durant the early and mid-Holocene, in other words between 11,000 and 4,000 ago, much more of the earth was covered by forests than today. During this period, monsoons brought abundant, well distributed rainfall throughout the year. But according to various geological and palynological data, a first significant reduction of forest areas began some 4,000 years ago, making place for savannah. This phenomenon was caused by a sudden decrease in monsoon rains which paleoclimatologists attribute to a drop in water surface temperatures in the Gulf of Guinea (3). However, the reduction in rainfall did not affect the heart of the great forests.

New fragmentation 2,500 years ago

Sediment and pollen records as well as the analysis of plant remains found on archaeological sites show that another disturbance occurred 2,500 years ago. Much more significant than the previous one, it had a strong impact on Central African forests, with the spreading of pioneer trees and herbaceous plants that are typical of degraded forests and the appearance of savannah.

The strong erosion associated with this phenomenon indicates that it was caused by dominant storm rainfalls and a shortened wet season. Due to the erosion caused by this type of rainfall over several centuries, many ancient soils were laid bare and “washed out”. Sediments carried away by the Congo River became very rich in aluminium and potassium as a result. It was the discovery of this high concentration in submarine deposits of the Congo River that led to the erroneous theory of “anthropological” intervention as an explanation for deforestation in Central Africa.

Present-day human activities often have a devastating impact on the environment, due to the strong geographic expansion of populations. However, in past ages, such activities cannot necessarily bare the blame for something like the major ecological disruption that affected forests in Central Africa between 2,500 and 2,000 years ago.

Research by archaeologists and paleontologists in fact shows that the extent of Bantu settlement was very small during this period and could therefore not have caused such a major disturbance. Only a profound change in the climate pattern of the entire sub-region could bring about such a change in the landscape.

Contributing Source : IRD

HeritageDaily : Archaeology News : Archaeology Press Releases

 

- Advertisement -

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Cliff Villages of Bandiagara – The Land of the Dogons

The cliffs of Bandiagara is a large geological escarpment rising above the surrounding flatlands in Mali that contains various archaeological sites and 289 ancient settlements.

Study Suggests the Mystery of The Lost Colony of Roanoke Solved

The Roanoke Colony refers to two colonisation attempts by Sir Walter Raleigh to establish a permanent English settlement in North America.

Drones Map High Plateaus Basin in Moroccan Atlas to Understand Human Evolution

Researchers from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) have been using drones to create high-resolution aerial images and topographies to compile maps of the High Plateaus Basin in Moroccan Atlas.

The Kerguelen Oceanic Plateau Sheds Light on the Formation of Continents

How did the continents form? Although to a certain extent this remains an open question, the oceanic plateau of the Kerguelen Islands may well provide part of the answer, according to a French-Australian team led by the Géosciences Environnement Toulouse laboratory.

Ancient Societies Hold Lessons for Modern Cities

Today's modern cities, from Denver to Dubai, could learn a thing or two from the ancient Pueblo communities that once stretched across the southwestern United States. For starters, the more people live together, the better the living standards.

Volubilis – The Ancient Berber City

Volubilis is an archaeological site and ancient Berber city that many archaeologists believe was the capital of the Kingdom of Mauretania.

Pella – Birthplace of Alexander The Great

Pella is an archaeological site and the historical capital of the ancient kingdom of Macedon.

New Argentine fossils uncover history of celebrated conifer group

Newly unearthed, surprisingly well-preserved conifer fossils from Patagonia, Argentina, show that an endangered and celebrated group of tropical West Pacific trees has roots in the ancient supercontinent that once comprised Australia, Antarctica and South America, according to an international team of researchers.

High-tech CT reveals ancient evolutionary adaptation of extinct crocodylomorphs

The tree of life is rich in examples of species that changed from living in water to a land-based existence.

Fish fossils become buried treasure

Rare metals crucial to green industries turn out to have a surprising origin. Ancient global climate change and certain kinds of undersea geology drove fish populations to specific locations.

Popular stories