Forest Management for Mitigation of CO2 Emissions: How Much Mitigation and Who Gets the Credits?

Forestry projects can mitigate the net flux of carbon (C) to the atmosphere in four ways: (1) C is stored in forest biomass — trees, litter and soil, (2) C is stored in durable wood product, (3) biomass fuels displace consumption of fossil fuels, and (4) wood products often require less fossil-fuel energy for their production and use than do alternate products that provide the same service. We use a mathematical model of C stocks and flows (GORCAM) to illustrate the inter-relationships among these impacts on the C cycle and the changing C balance over time. The model suggests that sustainable management for the harvest of forest products will yield more net C offset than will forest protection when forest productivity is high, forest products are produced and used efficiently, and longer time periods are considered. Yet it is very difficult to attribute all of the C offsets to the forestry projects. It is, at least in concept, straightforward to measure, verify, and attribute the C stored in the forests and in wood products. It is more challenging to measure the amount of fossil fuel saved directly because of the use of biomass fuels and to give proper attribution to a mitigation project. The amount of fossil fuel saved indirectly because biomass provides materials and services that are used in place of other materials and services may be very difficult to estimate and impossible to allocate to any project. Nonetheless, over the long run, these two aspects of fossil fuel saved may be the largest impacts of forestry projects on the global C cycle.