Our results show very clearly the breadth and the rapidity of the invasion of the chestnut groves by other species. These powerful natural dynamics are due to both the artificiality of chestnut monocultures and the lack of fitness of the species when subjected to natural competition under existing environmental conditions.
Without any anthropogenic intervention, this evolution will accelerate in the future because of the increasing senescence of chestnut orchard trees and coppice stools. Thus, foresters should know that without their intervention the chestnut groves will be lost.
A better understanding of this process is important because of the (still) wide distribution of chestnut stands in southern Switzerland and their role in the protection of the steep hill slopes of the south-facing foothills of the Alps. In addition, these changes will also have important cultural, economic, landscape and social repercussions. The size and complexity of the transformations that we see give political weight to the problem; the choices and decisions that must be made about the future function of the chestnut groves are fraught with difficulties and implications, not only for the current distribution of the chestnut but for the entire rural territory south of the Alps. In fact, the current evolution of abandoned chestnut groves can be considered just one of the typical consequences of the gradual diminishing of landscape management, such as fallow lands, new afforested areas, homogenisation of landscape patterns and so on. This can lead to an increased risk of natural hazards, as already demonstrated for the case of forest fires in southern Switzerland (Conedera et al., 1996).
We hope that this information about the natural dynamics of the chestnut belt in Southern Switzerland will contribute to the improvement of the decision-making instruments for proper land-use planning.