L'erosione dei sentieri in alta montagna. Indagini dendrogeomorfologiche e stime quantitative lungo alcuni itinerari della Valfurva (Sondrio)

The erosion of tourist trails in high mountain. Dendrogeomorphological analysis and quantitative evaluations on some paths in Valfurva (Sondrio, Central Italian Alps)

Abstract

The high mountain landscape is changing, following the climatic trend. Glaciers are retreating and new scenarios and mountain trails are now utilizable by tourists. The environment is somewhere affected by human impact due to the increased frequentation. Where mountain trails are cut on steep slopes a deepening of paths can be observed. In the present work the soil loss along some paths in the Upper Valtellina was estimated. Along paths located below the timberline a dendrochronological analysis was carried out in order to evaluate the damages on roots, and on tree growth. Samples of stems and exposed roots were collected from 34 living trees. Two reference chronologies were built for Larix decidua Mill. and Pinus cembra L.. The results show changes in the trees and roots growth in the last twenty years. The deepening of the trail has been extremely rapid on the lateral moraine of the Forni Glacier (13 mm in less than ten years) on the left side of the valley, frequented since 1995.