Palaeoforest in the Rivière des Galets

Recently discovered on the bed of the Rivière des Galets, at the edge of the Mafate cirque, the palaeoforest is a group of trees that died a long time ago. They grew one thousand years before people arrived on Réunion and attest to the existence of a large primary forest in the Bas region.

An outstanding site

The palaeoforest is a group of dead tree trunks conserved in their organic wood state. The observation and geological study of the trees suggest the forest grew on an initial mud flow in the river bed before being covered by a second mud flow.

The dead trees are preserved inside the detrital matrix. The sediment was carried away by a recent cyclone flood revealing the stumps and trunks of the rooted trees. In 2013, a rescue operation took samples from the remains before they would disappear into the river bed.

Dating and identifying the species

The trees were radiocarbon dated to the 2^nd to 6^th centuries CE. Specialists are working to identify the species in a bid to reconstruct an area of the island’s original landscape, while only relics of the primary forest now remain in Les Bas.

Tree no. 1 could be Foetida mauritiana, a tree endemic to the Mascarene islands. Now quite rare, it would have been relatively common before people arrived on the island.

In 2019, data from the palaeoforest site were used as part of a project to educate children on the media and information. The digital tool created as part of this initiative is available for everyone to use.