Climate science

Forests are a vital part of the carbon cycle

Scientists agree and the evidence is clear: the greenhouse gas (GHG) emissions we generate, primarily as a result of fossil fuels, are the leading cause of global warming and related volatile weather patterns. The negative impacts of climate change are a threat to the world’s forests, oceans, waterways and vital ecosystems.

Closely related to climate change is the earth’s carbon cycle. The carbon cycle refers to the continuous transfer of carbon from land and water to the atmosphere and living things. Forests are a vital part of this carbon cycle, both storing and releasing it in a dynamic process of growth, decay and renewal.

Curbing carbon emissions

Healthy forests can help cool the planet

The world’s forests help curb climate change and global warming by absorbing nearly a quarter of carbon emissions caused by human activity—primarily the burning of fossil fuels and converting regions to farmland and other uses. By sucking up that carbon, forests reduce the amount of CO2 in the atmosphere and in turn decrease the impacts of climate change.

This means keeping forests healthy is a critical part of removing harmful emissions and cooling our planet. Trees absorb carbon as they grow and when made into wood products, continue to store that carbon over their lifetime. Natural regeneration and planting continue this cycle. Managing our forests sustainably, increasing our use of wood products over carbon-intensive materials and maximizing their reuse and recycling is a smart climate solution.

Carbon calculus

Forests as carbon sources and carbon sinks

Forests can act as both carbon sources and carbon sinks. When trees burn or decay, whether by old age, fire, insect attack or other disturbances, they release carbon into the atmosphere. Carbon is absorbed through photosynthesis, storing the carbon in the tree’s trunks, branches, roots, leaves and soil. A forest is a carbon source if it releases more carbon than it absorbs. It is a carbon sink if it absorbs more carbon from the atmosphere than it releases.

For the past century, BC’s managed forests have been a significant carbon sink, steadily adding carbon to that already stored. In more recent years, the impacts of climate change—forest fires and insect attacks—have led to a shift in the province’s carbon balance, with some forested regions becoming a source of carbon.

 

The 35% solution

BC's forestry sector could deliver significant carbon reductions

Building more with wood, when paired with region-specific forest management practices, can deliver significant emissions reductions for the province, according to the Pacific Institute for Climate Solutions. Under the best-case scenario modelled by the researchers, they concluded that BC’s forestry sector could potentially contribute to 35 percent of the province’s 2050 emissions reduction target.

StructureCraft Manufacturing Facility, Abbotsford
Photo credit: StructureCraft Builders

Forest resilience

Planting for future climate conditions and restoring the carbon balance

A dynamic approach to forest management is helping restore the carbon balance of BC’s forests and make them more resilient in the face of climate change. Using the latest science, BC researchers—in collaboration with the Canadian Forest Service, the University of British Columbia (UBC), and the USDA Forest Service—are finding ways to minimize the impacts of wildfires and maximize the amount of CO2 absorbed by the province’s forests. By modelling a range of scenarios—such as different approaches to harvesting, silviculture and the use of bioenergy to replace fossil fuels—scientists are finding ways to adapt to warming temperatures.

One way the province is doing this is by researching growth rates and planting specific native tree species where future climate conditions can help them thrive. In fact, BC’s forests are growing one to three percent faster per year on average according to a study from the Pacific Institute for Climate Solutions.

For example, the black spruce—found in northern BC—is a native tree species that is growing twice as fast due to a warming climate. Another is western larch, which can now be planted north of its traditional range. With the right planning, climate change is and can continue to accelerate the regeneration of BC’s forests and even boost their carbon-absorbing benefits.

Locking carbon in buildings

How wood construction can help fight climate change

Sustainably-sourced wood products help reduce the impacts of climate change. Their carbon-locking capability makes them an eco-friendlier choice when compared with non-renewable materials with high emissions such as steel or concrete. It is one of the few structural building materials we can grow using the sun while absorbing harmful CO2 emissions from our atmosphere. Cement, on the other hand, is the source of about eight percent of the world’s carbon dioxide (CO2) emissions. Constructing more and taller structures with wood, and reducing our use of high-emission materials, such as steel and concrete, is a practical way to reduce the embodied carbon of our buildings. All things equal, the embodied carbon emissions of a wood structure are significantly less than a similar steel- or concrete-built structure.

Askew’s Uptown Supermarket, Salmon Arm
Photo credit: Derek Lepper Photography

Simplify the savings

Carbon Calculator by Canadian Wood Council

Use the Carbon Calculator by the Canadian Wood Council to quantify the benefits of building with wood. Specific wood product and building information is put into the Calculator and the tool provides estimates of carbon storage in the building and emissions avoided as a result of using less carbon-intensive materials. This includes how much time it takes Canadian and US forests to grow that volume of wood along with the associated carbon benefits—both the amount of carbon stored and the amount of greenhouse gas emissions avoided.

Life cycle assessment

Calculating environmental impacts of different building materials

Life cycle assessment is one of the best tools for examining the embodied carbon of building materials because it considers the greenhouse gas emissions associated with their production, transportation, construction, use and eventual disposal.

Various organizations have created online tools—embodied carbon in construction calculators—that take the whole lifecycle of products into account. Examples include Athena Sustainable Materials Institute’s Impact Estimator, Carbon Leadership Forum’s EC3 Tool, KieranTimberlake’s Tally and Bionova’s One Click LCA. Using these tools, building professionals can estimate the carbon footprints of their projects by plugging in the type and quantity of materials to test different options.

Audain Art Museum, Whistler
Photo credit: Derek Lepper Photography

Renewable building materials

Zero-carbon buildings and the role of wood

While net-zero buildings that use less energy to operate than they generate are a good start, they don’t go far enough to reverse the accelerating effects of climate change. To meet global targets, and stop the world’s average temperature from rising, estimates show that all buildings will need to be net-zero-carbon by 2050. And science is showing that is possible to construct zero-carbon buildings—even make them a carbon sink—by using renewable materials such as wood.

The choice of products and systems used to construct, renovate and operate buildings has a significant effect on achieving zero-carbon building targets. Wood products are responsible for lower air and water pollution and have less embodied carbon than other commonly used building materials. Factory-built, precisely-manufactured timber construction makes better use of resources and reduces the number of deliveries to a building site, in turn decreasing overall vehicle emissions. Scraps leftover can be repurposed or recycled as bioenergy. These benefits, along with wood’s ability to serve as a carbon sink, make timber buildings a compelling choice to help achieve zero-carbon construction and design.  ​

BC Passive House Factory, Pemberton
Photo credit: Ema Peter Photography, courtesy Hemsworth Architecture

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