Boreal forest and climate change

By WERNER KURZSat. Apr 19 - 6:14 AM

Recent media reports have suggested that logging is destabilizing the Canadian boreal forest and making it more susceptible to fire and insects, which could cause a catastrophic emission of greenhouse gases. The boreal forest is indeed under threat from climate change. Increased temperatures and changes in precipitation are already having impacts on the severity of forest fires and insect infestations. But these impacts are the result of global climate change, not local logging activities.

Natural disturbances dominate the carbon dynamics of the boreal forest. Fires in the boreal and taiga regions burn an average of 0.7 per cent of the forested land per year. But only 0.2 per cent of the managed boreal forest is harvested each year. The notion that this harvesting will result in the release of a major portion of the carbon stored in the rest of the boreal forest is not supported by science.

About 85 per cent of the area annually burned in Canada’s forests is the result of lightning strikes, and there is no scientific evidence that logging increases the area annually burned in the boreal forest. In fact, many insects prefer older stands that are less able to resist attack. This is the case for the current mountain pine beetle infestation in British Columbia, where fire suppression and a lack of harvesting led to large areas of mature pine forests. With warmer winters, the beetle was able to survive and spread well beyond its historic range. Although this infestation will lead to significant amounts of carbon release as trees decompose, salvage harvesting some of this wood to replace the harvest of live trees or using the material for bioenergy as a substitute for fossil fuel will reduce overall carbon emissions.

Forests play two important roles in the global climate system: First, they remove carbon from the atmosphere and store it in trees, litter and soil carbon; and second, they provide timber, fibre and energy to meet human demands. The International Panel on Climate Change (IPCC) – the UN organization that shared the Nobel Peace Prize in 2007 with Al Gore – concluded that "a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre or energy from the forest, will generate the largest sustained mitigation benefit." If logging were to stop in Canada’s boreal forest, then society’s demands would be met using materials with a higher carbon footprint than products from sustainably managed forests.

Sustainable forest management seeks to find the balance between many competing interests. Under a changing climate, the complexity of forest management has increased. We need to take into account not only the role of forests in storing carbon, but also how they respond to a changing climate and how we need to manage them differently to both mitigate climate change and adapt to the climate of the future. There are no simple solutions. Addressing these issues will require ongoing rigorous scientific analyses, consultation with many stakeholders and actions that are guided by scientific facts.

Dr. Werner Kurz is a senior research scientist with Natural Resources’ Canadian Forest Service, the lead scientist for Canada’s national forest carbon monitoring, accounting and reporting system and a member of the IPCC. For more information, go to carbon.cfs.nrcan.gc.ca/FAQ_e.html.