Interannual Variability of Water and Carbon Fluxes at a 100 Yr. Spruce Stand

Interannual Variability of Water and Carbon Fluxes at a 100 Yr. Spruce Stand

Christian Bernhofer, Thomas Grünwald and Patricia Mellmann Department of Meteorology, Dresden University of Technology, Pienner Str. 9, D-01737 Tharandt

At Tharandt, SW of Dresden/Saxony, water and carbon fluxes of a 100 yr. old spruce stand are investigated within the European FLUXNET initiatives (EUROFLUX and Carbo-Euroflux) since 1996. During the first 4 years considerable progress has been made in cooperation with other groups to: (i) establish reliable flux measurement hard and software for continuous operation, (ii) identify the major driving forces, and (iii) develop appropriate data gap filling techniques. Based on these steps the monthly and annual sums of carbon loss or gain of a typical central European managed stand were calculated. They show a clear and simple correlation mainly to PPFD, soil (or air) temperature, and soil moisture. The typical interannual variability of the driving variables at the site is recorded since the early 60ies. A regression model is applied to calculate the "estimated carbon sequestration" during more than 30 years and compared to forest inventory data. Catchment studies serve as an independent cross check for the accompanying water fluxes and as an indicator for drought effects on the carbon balance.