Weiterentwicklung der Kontrollstichproben am Beispiel des Kantons Glarus | Further development of permanent forest inventory; the example of Canton Glarus

In accordance with the revision of the forest law, a planning concept and new regulations for forestry planning have been drawn up for Canton Glarus. Owing to the size of Canton Glarus forest inventory is established at a cantonal level so that it can be related to other planning issues. The cantonal forest inventory is drawn up on the basis of previous inventories. From 1975 to 1993 a total of 3500 permanent sample plots were set up over three acres. In the follow-up inventory at a cantonal level the goal was to gather and analyse 30 important characteristics (growing stock, increment) of a sufficient degree of exactitude. In this way it was possible to reduce the size of the inventory by two-thirds, namely to 1135 sample plots. In addition, plots were rearranged in clusters with six sample plots in each because individual sample plots were too far apart. This makes it possible to change from one sample plot to another with shorter walking distances in between, an important consideration in sometimes difficult mountainous terrain. In smaller clusters, numerous individual sample plots still exist. Boundary conditions (10 500 ha of community forests),the measure of girth limit (16 cm) and sample plot size (3 ares)remained unchanged allowing the measurements to be used to calculate changes in increment, mortality and growing stock. The catalogue of inventoried criteria was supplemented with stability assessment and young forest surveys in order to be able to address new questions, such as the sustainability of the protective function of the forest. The work was put out to tender and awarded to qualified enterprises companies on the basis of fixed, net payment. In order to monitor and ensure quality control samplings were taken of 7% of the sample plots in the years 2001 and 2002. A changeover in the inventory system from the level of the enterprises to the level of the canton is indeed possible without having to invent a new system.