Since 1985, the condition of forests in Switzerland has been monitored through the Sanasilva Inventory. This is based on a systematic sampling programme, using a network of plots. Although the network provides representative results for Swiss forests, the network design is inappropriate for cause-effect research. The LWF plots are providing a variety of ecologically relevant data (including information on soils, vegetation, meteorology, pollutant deposition etc.). It is therefore important to have good information on the condition of the trees in the plots. At the same time, assessing the crown condition of trees in the LWF plots provides an important link between the results from this sub-programme and those of the Sanasilva Inventory.
- to determine the relationships between crown condition and a number of environmental parameters determined on site
- to provide a link between the LWF and Sanasilva sub-programmes
- to develop the basis for a better explanation of the trends recorded in the Sanasilva inventory
A full inventory of the crown condition of all trees >12 cm diameter is made in each LWF plot at the start of the programme. This is repeated at regular intervals, using a rolling assessment programme so that the work is spread evenly. An annual assessment of the crown condition of trees >12 cm diameter in a 50x50 m subplot is made. The assessment methods are based on those used in the Sanasilva inventory.
Inventories have been completed for the following sites: Alptal, Beatenberg, Bettlachstock, Celerina, Chironico, Davos, Isone, Jussy, Lägeren, Lantsch, Lausanne, Lens, Nationalpark, Neunkirch, Novaggio, Othmarsingen, Schänis, Visp and Vordemwald.
Completed and planned inventories (including the 50x50m subplots) are listed in Table 17.