The contribution of wood products to carbon sequestration in Portugal

Carbon sequestration in wood products in Portugal was estimated for the 1990 - 2000 period using two accounting approaches: the stock-change and the atmospheric-flow. Calculations rely on historical data for production and trade of wood products, and on typical values for their lifetimes. Carbon sequestration in wood products, calculated by the stock-change approach, increased from 310 Gg C yr(-1) in 1990 to 611 Gg C yr(-1) in 2000. The estimates of carbon sequestration using the atmospheric-flow approach, in the same period, varied from 322 Gg C yr(-1) to 783 Gg C yr(-1), and do not show the same increasing trend given by the stock-change approach, as they depend not only on the change in the stocks of wood products but also on their trade. The sensitivity analysis performed shows that the results are significantly affected by the parameters related with the lifetime of the products, the carbon fraction in paper and the biomass conversion factor.