Improving carbon estimates for Europe's forests
Scientists from the Carbo-invent consortium used statistical data from national and regional forests to determine biomass for entire trees. Together with carbon estimates from soil studies, this information was used to calculate forest carbon stock changes at national and European level. The project was part of the EU's commitment to the United Nations Framework Convention on Climate Change (UNCCC), enabling targets set by the Kyoto Protocol to be met. A forest resource projection model was used to calculate carbon budgets for large-scale forests in six EU countries - Austria, Spain, Germany, Ireland, Finland and Sweden. Biomass carbon was estimated for different tree species and age classes from volume measurements. Biomass expansion factors (BEFs), ratios refined within the project, were used for the conversion. Differences in the levels of carbon per hectare in the test countries could then be compared to the average biomass per hectare. Researchers assumed that the area of forest did not alter during the study period and any changes in carbon stocks were due to the death or ageing of the trees. However, the number of trees felled depended on a range of factors including market prices, demand for wood and storm damage. As a result changes in tree biomass found in the computer model may differ from what actually occurs. The forestry model was also used to estimate the amount of leaf litter in the soil and the results applied to a soil carbon model, YASSO, which simulates litter decomposition. National soil carbon estimates for Austria, Germany, Finland and Sweden were found to be lower than values obtained from the model. However, Irish and Spanish soil carbon estimates were found to be higher than in the simulation. The differences could be due to an overestimation of decomposition rates in organic soil and past changes in forestry management and environmental conditions. The Carbo-invent approach enabled different data sources to be used, giving a better estimation of carbon stock changes in forests throughout Europe. The result was the development of more accurate national forest inventories which can provide more effective reporting of greenhouse gas emissions.
