This paper discusses an assessment of the optimal use of biomass in Western Europe for the long term (2010-2030) for reducing greenhouse gas emissions. The assessment is based on a linear programming model for the Western European energy and materials system, called MARKAL MATTER 4.2. The goal of the study was the comparison of the cost-effectiveness and the interactions between bioenergy, biomaterials and afforestation strategies in comparison to other greenhouse gas emission reduction strategies. The results suggest that the use of biomass for energy and materials applications will increase by up to 200 Mt (compared to the case with no permit price) if greenhouse gas policies are introduced. The main increase occurs in the production of transportation fuels and substitution of petrochemical feedstocks and electricity generation from waste and residues. Afforestation offers a cost-effective competing land-use strategy. The total contribution of biomass strategies is an emission reduction of up to 400 Mt CO2 equivalents (9% of 1990 emissions).