Waldflächenentwicklung der letzten 120 Jahre in der Schweiz

Abstract

Development of forest area in Switzerland within the last 120 years Historical maps provide a useful source for spatial landscape analyses as they represent a generalized reflection of geographical reality over large areas at a certain time. Digitization and georeferencing of analog maps help to make such analyses more efficient. In Switzerland, the forest area has grown since the mid 19th century according to statistics of the federal government and the cantons. These statistics, however, provide a limited basis for regional analyses of changes in forest area. In this study, the forest areas in 1880, 1915, 1940 and 2000 were estimated based on analyses of the Topographical Atlas of Switzerland (Siegfried maps [1880Siegfried maps [1915, and 1940]), and of the Topographical Map (2000). Using a sample of 20 638 plots, analogous to the aerial photo-interpretation of the Swiss National Forest Inventory (NFI), a forest/non-forest decision was made for each time cutting. Overall, in Switzerland the forest area increased by 21.6% from 1880 to 2000. This is much less than what revealed the analysis of statistical sources due to differences in the methods and forest definitions used. Considerable regional differences could be detected, with one general trend from north to south and another from east to west. In most regions with strong urban development, the forest area is stagnating or has slightly decreased. The increase in forest cover has taken place mainly in the Alps and the Southern Alps.