The Iron Age environment of Dibamba, a site in coastal Cameroon

The archaeological site Dibamba 1 lies in the outskirts of Douala, Cameroon’s largest city. Formerly coastal rain forest covered the region, but intensive land use has severely altered the vegetation. Today the site is surrounded by plots with cultivated crops. Rescue excavations in the course of the construction of a power plant in 2008 revealed 218 pits dating to several settlement periods spanning the last 2000 years.

In order to reconstruct the influence of land use onto the woody vegetation in the vicinity of the settlement, archaeobotanical samples were taken during the excavation and charcoal and charred fruits and seeds were analyzed.

30 charcoal types were recognized, described and documented. Their identification, i.e. attribution to different tree taxa, was time-consuming, due to the high diversity of woody species in the West African rainforest and insufficient wood anatomical identification keys. The charcoal types had to be compared to samples from the comparative wood slide collection at Goethe University Frankfurt, to the collections of the Royal Museum for Central Africa in Tervuren (Belgium), as well as to anatomical descriptions published within taxonomic publications. Therefore only 13 samples containing 511 fragments have been analyzed so far. Charred fruit and seed remains were analyzed from 29 samples. Their identification is mainly based on comparison with the collection of fruits and seeds in Frankfurt.

The results point to the presence of clearings in the vicinity of the settlement where wild fruits and fuel wood had been collected. The fruit and seed remains of some of these wild plants are documented for the first time. As elsewhere in archaeological sites from the West African rainforest, endocarps of the oil palm (Elaeis guineensis) are the most frequent find. Charred fragments of leaf stalks and stems probably also originate from oil palm. Charcoal fragments of pioneer taxa document that some fuelwood was collected in clearings during the first stages of regrowth. Shade-tolerant taxa, typically dominating in later stages of forest regrowth, were present in the charcoal assemblage as well. These charcoal fragments might derive from trees that had been cut when setting up new fields in old fallows.

Increasing percentages of pioneers versus shade-tolerant taxa in the younger samples might point to shorter fallow periods and thus to intensification of land use over time. However, the number of analyzed samples is not sufficient for any conclusions because random variations and statistically significant differences cannot be distinguished yet. So far the influence of European contact is only visible in the archaeological but not in the archaeobotanical finds.

Publications:

Höhn, A. & Neumann, K. (2018): Charcoal identification in a species-rich envrironment: The example of Dibamba, Cameroon. IAWA Journal 39(1): 87-113.