This paper discusses and contrasts two main roles of forestry in light of the debate on the global climate. As the main problem is related to the increases of the CO2-concentration in the atmosphere, forests may be viewed as part of the alleviation of the problem through their function as (i) carbon storage, since a growing forest extracts atmospheric CO2 and fixes it as carbon in biomass, and as (ii) a source of biomass for energy production, which may replace fossil fuels and thus reduce CO2-emissions. The addition of the carbon storage value to the traditional focus on the forest's timber value is well known in the economics' literature, and it's main effect is to increase the rotation length of the forestry. In this paper we also add th...