Forest-CH

Environmental Controls on Forest Growth in Switzerland

Context

The growth of Swiss forests is currently being assessed based on infrequent forest inventories from the Landesforstinventar (LFI; about every 10 yrs). Thus, forest growth information is available to the decision-makers at cantonal and national levels only with a rather coarse temporal resolution and a substantial time lag (about 4 yrs after the inventory is completed), which prohibits annual reporting (e.g. for the Kyoto protocol), but also limits an advanced understanding of the environmental controls of forest growth in Switzerland at inter- or even intra-annual time scales.

At the same time, 17 long-term monitoring sites (LWF, LTER) are equipped with different types of stem growth bands, so-called dendrometers, which record tree stem growth at different temporal resolutions, from annual to 30min time spans, since 1998/2001. At one of these sites, a CO₂ flux tower is running since 1997, providing ecosystem C budget information. Although all of these data could act as a great data "treasure" to estimate past and to measure and understand current forest growth, a comprehensive, Swiss-wide assessment of these dendrometer data has not been done so far. Thus, this „treasure“ is heavily underused.

Objectives

Together with relevant stake-holders (WSL, FOEN), we want (1) to compile and quality check different data sources on forest growth, (2) to assess environmental controls as well as interacting stresses on forest tree growth at different temporal scales (30 min to decade), and (3) to synthesize and to report policy-relevant knowledge on cause-effect relations in Swiss forests and to write a joint green paper on policy demands for FOEN and Swiss policy options arising from two conventions (UNFCCC; CLRTAP).