Archaeological excavations continue on the section of A9 autoroute through Finges Forest in Canton Valais, around 20km east of Sion.
Over the past two decades, excavations have uncovered a Roman road and research continues on housing and agricultural sites in the area.
Soil removal work will begin in mid-April in the area of the hamlet of Pfyngut, which is a nature reserve and one of the largest continuous Scots pine forests of Europe.
The canton has reassured that the excavations will have no further impact on the progress of construction work on the A9 motorway.