DYNAMICS AND POTENTIALS OF CARBON SEQUESTRATION IN MANAGED STANDS ANDWOOD PRODUCTS IN FINLAND UNDER CHANGING CLIMATIC CONDITIONS

Carbon (C) sequestration was studied in managed boreal forest stands a nd in wood products under current and changing climate in Finland. The C flows were simulated with a gap-type forest model interfaced with a wood product model. Sites in the simulations represented medium ferti le southern and northern Finland sites, and stands were pure Scots pin e and Norway spruce stands or mixtures of silver and pubescent birch. Changing climate increased C sequestration clearly in northern Finland , but in southern Finland sequestration even decreased. Temperature is currently the major factor limiting tree growth in northern Finland. In southern Finland, the total average C balance over the 150 year per iod increased slightly in Scots pine stands and wood products, from 0. 78 Mg C ha(-1) per year to 0.84 Mg C ha(-1) per year, while in birch s tands and wood products the increase was larger, from 0.64 Mg C ha(-1) per year to 0.92 Mg C ha(-1) per year. In Norway spruce stands and wo od products, the total average balance decreased substantially, from 0 .96 Mg C ha(-1) per year to 0.32 Mg C ha(-1) per year. In northern Fin land, the total average C balance of the 150 year period increased und er changing climate, regardless of tree species: in Scots pine stands and wood products from 1.10 Mg C ha(-1) per year to 1.42 Mg C ha(-1) p er year, in Norway spruce stands and wood products from 0.69 Mg C ha(- 1) per year to 0.99 Mg C ha(-1) per year, and in birch stands and wood products from 0.43 Mg C ha(-1) per year to 0.60 Mg C ha(-1) per year. C sequestration in unmanaged stands was larger than in managed system s, regardless of climate. However, wood products should be included in C sequestration assessments since 12-55% of the total 45-214 Mg C ha( -1) after 150 years' simulation was in products, depending on tree spe cies, climate and location. The largest C flow from managed system bac k into the atmosphere was from litter, 36-47% of the total flow, from vegetation 22-32%, from soil organic matter 25-30%. Emissions from the production process and burning of discarded products were 1-6% of the total flow, and emissions from landfills less than 1%.