Easier definition of forest limits

The modification of the forest law of March 16, 2012 now allows cantons to define static limits to forests outside building zones, in areas where the canton wants to prevent growth in the forest area. These areas must be designated in the cantonal master plan. The maintenance of open environments must not only be ensured legally by static forest limits, but also guaranteed in the long term by means of appropriate exploitation measures. These are often areas that are of great importance for species diversity or for the landscape.

The definition of static tree limits locally removes the notion of dynamic tree limits. Consequently, a new stand outside this limit is not considered forest within the meaning of the law and can be removed without authorization to clear.

SPATIAL SA and its partner Haller Wasser + partner SA were chosen by the Cantonal Office of Agriculture and Nature, for their complementarity and their ability to implement new solutions. The mission concerns the development of specifications, in preparation for the launch of a complete call for tenders. Were carried out in agricultural zone :

1. testing various techniques for acquiring forest limits, with robust methods reconciling technical execution and legal validity,
2. two measurement campaigns in real conditions :
   • a test over a distance of 1 km,
   • unsampling over ~20 km.

SPATIAL SA has tested various methods based on cantonal data, digitalization and drone acquisition.

This last technical solution, allowing definition with a density of approximately 1000 points per m2, was particularly attractive because it offers :

• fine-grained As-Built digitization of forest boundaries,
• a catalog of valuable images in STATE – Owners discussions,
• an irreproachable observation at a given time of the state of the vegetation.