Indicator 4.1.2 - Forest ecosystem carbon storage by forest type and age class
supporting indicator


Forest carbon storage refers to the total amount of carbon contained in all the components of the forest ecosystem at a given time. This includes the carbon found in living biomass (above and below ground), in dead organic matter (including standing snags and fallen woody debris), and in soils (organic and mineral layers). Forests play an important role in the global uptake and storage of carbon, in the form of carbon dioxide (CO₂), and in its release to the atmosphere. Since CO₂ is the most abundant greenhouse gas found on earth, forests can affect climate change by sequestering and releasing CO₂.

Canada's forests are composed of tree stands of different ages and the distribution of age classes in the forest is an important factor in understanding carbon stock flows. Younger forests, despite holding less carbon per hectare than older forests, generally have the capacity to sequester carbon at a higher rate than their older counterparts. However, older stands typically hold more carbon because they have been accumulating it for decades, if not centuries. Therefore, disturbances affecting older stands will have a stronger impact on carbon emissions because more carbon will be lost to the atmosphere. The harvesting of forests, despite not resulting in an immediate release of carbon to the atmosphere, will also modify the composition of forest stands and affect carbon balance.

It is important, therefore, that we monitor the total carbon found in various forest age classes and forest types in Canada to better understand the effects of natural and human-caused disturbances on these carbon pools as well as the potential impact on the global carbon budget.

This indicator measures the total amount of carbon stored by Canada's forest ecosystems and tracks the relative contribution of hardwood, mixedwood, and softwood stands to the carbon stocks of a region. Hardwood stands are composed of more than 75% hardwood, while mixedwood stands contain between 25 and 75% hardwood, and softwood stands comprise less than 25% hardwood.

As with Indicator 4.1.1, current national estimates of the amount of carbon stored in Canada's forests are unavailable due to refinements being made to Canada's carbon budget model. However, an earlier version of the model used in the 2000 C&I report concluded that Canada's forest ecosystems contained 84.4 Gt of carbon, 82% of which was stored in forest soil and litter. It also demonstrated that most of the carbon stored in living forest biomass is found in older stands.

The previous case study represents the type of data that will soon be available on carbon storage for all Canada's forest ecosystems.