The coordinates of all points on the ground make it possible to generate digital elevation models (DEM) of the ground and canopy, the difference between the two corresponding to the height of the vegetation.

Last March, 11,000 hectares of the Forêt de Haye near Nancy were thus overflown by a plane equipped with a laser system emitting five beams per square metre to the ground.  In total, more than a billion and a half points were recorded during this scan of the forested region.
Patient collaborative work by INRA, the ONF and the Regional Archaeology Service (Metz) in this forest has already made it possible to map – on foot – part of the largest Gallo-Roman site known in Europe.
Support from the Regional Council for Lorraine and the European Union, and a partnership between the ONF, the DRAC for Lorraine and INRA, enabling the synergistic application of different skills, made it possible to initiate this project, the largest to date in any French forest.

The first images resulting from the processing of computerized data are now available, and suggest the possibility of highly promising research opportunities and applications.  As well as known structures such as the Camp d’Affrique, and those which had gradually been inventoried, a multitude of ancient structures – walls, ditches or terraces – are appearing for the first time.
The precise location and characterization of archaeological remains, which are very numerous in the Forêt de Haye, will thus progress very rapidly.  This technique could then be transposed to other forests. 
These data will provide a clearer understanding of the impact of Gallo-Roman farming on the diversity and fertility of modern forest ecosystems.  In addition, it may be possible to estimate tree height using this method, so that in the longer term – and this is a challenge of this research – the quantity of timber available.

The technique used here constitutes an exceptional tool which will help with the development of forest populations and management of the heritage and ecology of a much frequented and emblematic suburban forest.