1The Amazon forest is not homogeneous. It consists of a mosaic of habitats that managers are striving to map out, as they were unable to attain objective field surveys. In French Guiana, this observation resulted in a partnership between ONF, IRD and Cirad in the early 2000s, with a view to developing remote detection techniques and extrapolating the knowledge gained from the field.

Inselberg in the French Guiana forest.

••• Field surveys and remote detection tools are used to map out forest habitats in French Guiana •••

2Researchers decided to use data from the SRTM US satellite, whose radar waves provide access to geomorphology, i.e. the spatial organisation of the relief and soil on the scale of the territory. This approach echoes the research in soil science which, in the 1970s-1980s, showed that variations in the physical-chemical properties of soil impact the species composition of the community of trees that settles there. These variations are caused by the alteration, due to surface erosion, of very ancient soils which were formed under different climatic conditions from those of today.

Aerial view of the French Guiana forest.

3In fact, geomorphology can be used to determine not only the nature of soil but also the type of forest that develops on it. This methodology, combined with field surveys, made it possible to draw up a catalogue of around 20 forest habitats in French Guiana. Published in 2015, it has quickly become instrumental in devising forest management plans. This document drew the attention of forestry managers in neighbouring countries, including Suriname and the Brazilian State of Amapa, with whom IRD is currently working to implement the same approach. More recently, the same kind of mapping process was initiated in the Congo Basin in Central Africa, which features the world’s second largest tropical rainforest.

“From the beginning, ONF, in its capacity as forestry manager, assumed its responsibility, in particular in terms of the need for a better understanding of how to manage the surrounding ecosystem. To supplement their internal skills, ONF quickly developed partnerships with research organisations, including Cirad and IRD. These partnerships are continuing to this day, within the framework of projects such as Habitats or Dynfordiv, driven by the continuous improvement of the principles and rules governing the management of the French Guianan tropical rainforest.” 
Olivier Brunaux, Regional Directorate of French Guiana, head of the Cayenne Territorial Unit