Problems to be solved
The project addresses the controversial requirements set by the Kyoto Protocol and the Biodiversity Convention. The Kyoto Protocol seeks for biological sinks in order to balance fossil fuel emissions, and there is an economic stimulus for plantations with high productivity levels. These 'Kyoto Forests' may not be sustainable due to depletion in soils and may also result in a loss of biodiversity in plants and in soil organism. The effects on carbon stocks in the soil are largely unknown. There are experimental indications that productivity increases with diversity, and that in the long-term mono-cultures can result in soil degradation.
Scientific objectives and approach
The overall objective is to quantify carbon (C) sinks and sources in European semi-natural and managed forest ecosystems from measurements of changes in C stocks. The project will quantify effects of plants and soils on carbon fluxes under variable inputs of nitrogen and management regimes. Furthermore, it will predict and verify fluxes at the stand scale, which can be used at larger scale modelling and will also investigate the interaction of plant production and soil carbon decomposition with biodiversity over a broad range of N-depositions and environmental regimes. This will be achieved by continuous measurements of net ecosystem exchange (NEE) within a number of forest stands to assess above and below ground ecosystem processes and to quantify the main components of the C sinks. Since chronosequences provide possibilities for temporal representation and spatial integration, this approach will be used to quantify the effects of vegetation and soil organic matter on ecosystem C fluxes over a rotation period and in relation to atmospheric nitrogen (N) deposition. Biogeochemical models indicate that forest after disturbance by logging, may be a C-source for as long as 30 years despite actively regeneration. The effects of management on ecosystem C fluxes, and in particular those management practices that may convert a forest from a C sink into a C source will examined. It remains at present unresolved to what extent biodiversity determines net primary production (NPP), heterotrophic respiration and accumulation of soil organic matter. This will be analysed by investigating the interaction among plant production, decomposition of soil organic matter and especially of soil microorganisms, over a broad range of environmental and forest management conditions. The test and application of a biogeochemical model on a broader range of environmental conditions, species and management options for interpretation and prediction of net carbon fluxes as required by the Kyoto Protocol complete the work.
Expected impacts
The project contributes to the decision making process of negotiation on the Kyoto Protocol by separating effects of plant production and soil organic matter decomposition on the net carbon balance of forest and its interaction with the nitrogen cycle and management regimes. The project will deliver data to governmental forest administrations, which will enable estimate of the biological sinks and sources in European forests.