Net Ecosystem Carbon Dioxide Exchange Dynamics in a Pinus cembra Forest at the Upper Timberline in the Central Austrian Alps

Horn

2005

S. 233-242

4 Abb., 2 Tab., 34 Lit

Artikel aus einer ZeitschriftUnselbständiges Werk

200128742

We studied net ecosystem carbon exchange dynamics in a cembran pine (Pinus cembra L.) forest ecosystem at the timberline cotone of the Central European alps from October 7, 2001 throughout January 21, 2003. Chamber measurements of CO2 gas exchange of the foliage, woody tissue respiration, and soil surface CO2 efflux were used to identify the contribution of these components to the net ecosystem carbon sequestration and total ecosystem respiration. Seasonal variations in net ecosystem carbon exchange dynamics were primarily controlled by the prevailing temperature and irradiance. Annual net primary production estimated for 2002 was 1610 g C m-2 y-1 and total ecosystem respiration was 1247 g C ,2 year 1-. Annual carbon efflux from the foliage, branches, stems, coarse roots, and the soil surface was 273, 846, 45, 50, and 33 g C m-2 year-1, respectively. Net ecosystem production was 363 g C m-2 year-1, leading to a ratio of net ecosystem production to gross primary production of 0.23, consistent with values reported for temperate coniferous forest ecosystems, but higher than values reported for boreal coniferous forests. Due to low soil temperature and supra-optimal soil water availability soil surface carbon efflux was relatively low and contributed to only 3 % to total ecosystem respiration. Nevertheless, our data indicate that timberline associated Pinus cembra forest ecosystems in the Central Austrian Alps act as relative powerful carbon sinks.