A project-level assessment of monetary and carbon costs and benefits for five classes of global warming response options in the forest sector is attempted for typical Brazilian conditions. Options considered are: silvicultural plantations (for pulp, charcoal and sawlogs), sustainable timber management and reduction of deforestation. Comparison of pulpwood and sawlog plantations with the vegetation characteristic of deforested areas indicates a modest carbon benefit. Plantations for charcoal can produce a substantial carbon benefit through fossil fuel substitution, but much of this calculated benefit disappears if discount rates greater than zero are applied to carbon. Sustainable timber management, when compared with existing forest, represents a net carbon loss, accumulation of carbon in wood products being insufficient to compensate for biomass reduction over a 100 year time scale. Reduction of deforestation has great potential as a global warming response option, its per-hectare carbon benefits being approximately four times that of silvicultural plantation establishment for pulp and sawlogs over a 100 year period. The costs of reducing deforestation are difficult to assess, however, due to the importance of government policy changes such as removal of land speculation and land tenure establishment as motives for clearing. Although these changes would not cost money and would have tremendous carbon and other benefits, they have not yet occurred.
