Forests play a role in mitigating climate change in various ways: trees absorb atmospheric carbon as they grow, help to keep water and soil healthy, and can cool cities in hot summers.
Harvesting trees and ensuring regeneration can also play a role in climate change. Indeed, trees store carbon, and so do the products made from them. That is particularly true for structural lumber like 2x4s and advanced building products like cross-laminated timber.
Like the science of forest management, the science of how to produce forest products has also advanced over the last 125 years. The two main components of harvested wood—lignin and cellulose—can be used in many applications: fuels and bioenergy, pharmaceuticals, cosmetics and textiles, to name a few. Wood and its components can be used and reused: lignin and cellulose can be re-used four or five times before they begin to degrade.
Products that come from the forests, especially wood products, can help us reach our climate change goals by reducing greenhouse gas (GHG) emissions in two main ways:
- Using long-lived wood products, like building materials, to physically store carbon, expanding carbon storage outside of the forest
- Substituting carbon-intensive materials, such as fossil-fuel-based products, with wood products and their byproducts as lower-carbon alternatives.
Promoting circularity through the recovering, recycling and reuse of wood products, amplifies the benefits from storage and substitution on climate change.
How wood products fit into the natural carbon cycle:
Image summary
Circular infographic showing how Canada’s forests are part of the carbon cycle. Healthy forests store carbon, while decaying forests release it. About 0.2% of forests are harvested each year, and wood products store carbon throughout their life. Residues from forests are used in renewable energy and biorefineries. Reforestation and sustainable forest management ensures the carbon cycle continues. Recycled wood also keeps carbon stored.
Bioenergy with carbon capture and storage (BECCS) provides opportunities for net-negative emissions and the potential to remove carbon from the atmosphere, which is expected to be needed to offset remaining emissions in other sectors. The CO2 from bioenergy that is normally released and returned into the natural carbon cycle can be captured and stored, permanently removing carbon from the cycle.
Canada’s sustainably managed forests and integrated value chain mean that forest bioenergy is produced using harvest residues, industrial waste and byproducts from primary manufacturing processes, as well as trees damaged by natural disturbances and material removed to mitigate fire risk. Using biomass energy does not increase harvesting rates. It gives purpose to low-value and undesired feedstock which would have otherwise been left to decay.
Carbon storage in wood products
Forests store more carbon than other land-based ecosystems. Wood-based materials have the unique benefit of being able to store carbon that they absorbed before harvesting. Even though a portion of wood and its stored carbon can be lost during the harvesting and processing of wood products, wood products continue to act as carbon reservoirs, storing the remaining carbon throughout their lifespan, effectively delaying carbon emissions for several decades. The longer a wood product is in use, the longer carbon will remain stored within the wood. Using wood as a construction material is one example of long-term carbon storage, as buildings generally have long lives.
Using wood products as substitutes for fossil-based products
The forest sector prioritizes the use of the whole tree in order to maximize economic value. Higher value products like mass timber and lumber can be used as an alternative to more carbon-intensive building materials, for example in the construction of multi-residential buildings. Lower-value wood residues can be turned into renewable energy, lessening demand for fossil fuels. Residues can even be broken down further into its components (e.g. cellulose, hemicellulose and lignin) to produce chemicals and other materials.
Using wood products in buildings
The manufacturing, transportation and installation of wood-based materials use less energy and emit fewer GHGs and pollutants over their life cycle compared to other construction materials.
- For example, 2,325 m3 of Canadian timber was used to construct the Science Collaboration Centre and Support Facility in the Canadian Nuclear Laboratories in Chalk River, Ontario, reducing GHG Emissions by approximately 1,580 tonnes of carbon dioxide equivalent (CO2e), with 971 tonnes of CO2e sequestered and stored in the timber and 609 tonnes of CO2e avoided by substituting traditional construction materials with wood-based low-carbon materials.
Using wood products in innovative biomaterials
- Biomaterials made with wood fibre can include plastics, textiles, pharmaceuticals, lubricants and adhesives, which traditionally use fossil-based inputs.
- Lignin, an organic chemical that binds fibre together in plants and trees, can be used to replace bitumen in asphalt to reduce its carbon intensity and as an electrical conductor for use in electrical vehicle batteries.
Using wood products in bioenergy
- Residues and lower-value forest biomass have traditionally been used to manufacture solid biofuels (e.g. wood pellets used to produce energy) but are also increasingly being used for advanced liquid biofuels (e.g. biocrude, sustainable aviation fuel) and gaseous biofuels (e.g. synthetic gas, hydrogen). Biofuels can replace fossil fuels and thus reduce net carbon emissions.
- Bioenergy is used in wood product facilities, reducing industrial emissions by displacing fossil energy, but can also be used to provide readily available clean electricity and heat to communities which can in turn improve local energy security, reduce fossil fuel consumption and reduce the risk of pollution from fuel spill contamination.
Climate change presents forest management with new challenges but also new opportunities to increase the positive impact of forest products. While climate change increases the risk of forest fires, pests and disease in Canada’s forests, some landscape management activities, such as forest thinning for forest fire mitigation, improve community resilience and create wood residue which can be developed into marketable wood products with economic value. However, further efforts are required to overcome obstacles including the costs of transporting wood residue to facilities. Sustainable forest management practices will continue to be an important aspect of mitigating the impacts of climate change on Canada’s forests, while also ensuring that the forest sector stays a relevant player in Canada’s path to net-zero emissions.
Sources and information
- Canada Energy Regulator. (2023). Canada’s energy future 2023.
- Food and Agriculture Organization of the United Nations. Climate change mitigation and harvested wood products: Lessons learned from three case studies in Asia and the Pacific. Bangkok, Thailand.
- United Nations Economic Commission for Europe. Carbon storage in harvested wood products (HWP).