Actively managed forests have the greatest climate change mitigation benefit
In the long run, the forest will benefit climate change mitigation more if active silviculture methods are practiced and forest products are used to replace fossil energy and energy-consuming construction materials. About 470 kg of carbon dioxide emissions are avoided for each cubic meter of biomass harvested in Sweden. These results were recently published in the journal Forests. However, the forest has the potential to influence climate change mitigation even more.
The forest’s potential for climate change mitigation is considerable, the amplitude being determined by how much we can increase growth or availability of forest products and by how we prioritize its use, says Tomas Lundmark, Professor in Forest Management at Swedish University of Agricultural Sciences and researcher for the Future Forests program.
Sustainability requirements from EU
In order to clearly see the influence of forest and forest products on greenhouse gases (GHG), the EU strives to expand the sustainability requirements established for liquid fossil fuels to include solid fossil materials. Additionally, there is an ongoing discussion about how to evaluate and ensure that bioenergy generated from forests truly contributes to reduced greenhouse gas emissions.
The debate about forest generated bioenergy is challenging because there are different opinions about how to calculate GHG balances for forested bioenergy systems. Some studies indicate that bioenergy from forest biomass can generate high GHG-emissions in the short run. However, these studies have only included single actions within single stands in the analysis. For example, they neglect that in forested countries like Sweden large landscapes are managed as forest systems, where management activities in one place are coordinated with activities elsewhere in the system, beyond the specific stand. Hence, a steady flow of harvested wood will not be possible in sufficient volumes from an individual stand but can be extracted from a landscape-level system. The same applies for carbon emissions, as sequestration in one stand offsets emissions from another.
Tomas Lundmark says that to understand and describe the forest´s part in climate change, we have to enlarge the picture and include the whole silviculture sector—how forestry influences the amount of carbon sequestered within the forests, and how the production of bioenergy and other forest products influence GHG emissions by replacing fossil fuels and fossil products. Lundmark believes it won’t be enough to simply consider the CO2 balance after individual actions within individual stands and extrapolate the numbers.
Leave the forest for free development
Researchers within Future Forests have also analyzed what will happen with the forest during free development, without any management. In the short term, the results suggest this is a climate-friendly practice. Every cubic meter of biomass sequesters 700-900 kg CO2. However, sooner or later the forest will reach a point where it stops growing (due to age), takes up less CO2, and eventually dies, releasing CO2 back to the atmosphere. A dense and old forest also increases the risk of fires, storms, and insect infestations that result in large CO2 emissions.
When considering leaving the forest for free development because of the climate, one should ensure that there are other ways to meet the society’s need for wood and energy, says Tomas Lundmark.
Researchers within Future Forests took into account Sweden’s export of large amounts of forest products. Approximately 80% of climate change mitigation benefits from Swedish forest management are exported abroad.
The recently published study concludes that if we continue to manage the forests in Sweden as we do today, forestry will continue to contribute to avoided and/or reduced CO2 emissions of approximately 60 million tons annually, which is in the order of the current annual emissions. With forest practices focused on increased productivity of forest biomass, these climate change mitigations can increase even more.
Press photos (May be published freely in connection with articles about the study. Photographer must be specified.)
Forest harvest. Photo: Anders Esselin
Wood stack. Photo: Anders Esselin
Article in Forests:
Lundmark, T., Bergh, J., Hofer, P., Lundström, A., Nordin, A., Poudel, B.C., Sathre, R., Taverna, R., och Werner, F. (2014) Potential Roles of Swedish Forestry in the Context of Climate Change Mitigation, Forests 2014, 5(4), 557-578.
Professor Tomas Lundmark
Department of Forest Ecology and Management
Swedish University of Agricultural Sciences
070-631 74 12
Communicator Annika Mossing
Swedish University of Agricultural Sciences