Poster, International Symposium Soil processes under extreme meteorological conditions, Bayreuth: 2007-02-25 - 2007-02-28
Abstract:
Fine roots are a crucial element of carbon and nutrient cycling in forest ecosystems. In many forests, more than 50% of the assimilated carbon is transferred to the fine root system. However, the impacts of predicted climate change on structure and dynamics of fine root systems as well as on the carbon release to the soil by fine root decomposition remain unclear. Our aim is to investigate the effects of possible climate change scenarios characterized by increased summer drought and winter frost due to less precipitation in summer and winter on fine root mass and distribution in an old-growth forest. For that purpose, 9 research plots of 20x20m were selected in a Picea abies L. stand representing three treatments (freezing/ thawing, drying/ wetting, control) in triple replication. We took soil cores from all plots to analyze fine root distribution up to 30 cm mineral soil depth. The results showed that both bio- and necromass of the fine roots were highest in the organic layer and decreased strongly with depth. In order to analyze the effects of enhanced frost, we took root samples before, during and after a winter manipulation in 2005/06 from the organic layer of those plots, where snow has been removed and compared them with samples taken at control plots. In summer 2006 we analyzed fine root bio- and necromass at roofed plots and controls in the same way to investigate the effects of enhanced drought. We present data on the effects of the experimentally increased frost and drought on the fine root system of Norway spruce as well as changes in fine root litter decomposition due to these manipulations.