Forest products reduce our climate footprint

The levels of carbon dioxide in the Earth’s atmosphere have been measured since the 1950s, and the figures show a constant rise since records began. It is likely that this increase has been happening since the Industrial Revolution, when fossil-bound carbon dioxide (CO2) began to be released. This has led to climate change in the form of rising temperatures, higher sea levels and changing weather patterns. The effects of climate change are now making themselves felt in many different ways, posing the greatest challenge of our age. Together we need to reduce emissions, and a major part of this involves switching from fossil raw materials to renewables.

When it comes to reducing the human influence on the climate and adapting society to climate change, the forest has a key role to play. This is because the forest serves as a carbon sink. As forest grows, absorbing carbon dioxide and releasing oxygen, carbon is bound up in the trees. The carbon sink in the forest increases when forest growth is greater than the amount of wood harvested.

The carbon sink comprises a green circular flow of carbon

When the trees are harvested, the products continue to bind carbon for their entire service life. For climate reasons, it is therefore best to maintain active forestry that generates plenty of biomass for timber. As a raw material, wood can be processed into products for use in sustainable building. Wood counts as our only renewable construction material because the growing forest absorbs carbon dioxide from the atmosphere and, through photosynthesis, converts solar energy, carbon dioxide and water into carbohydrates, which form the building blocks in the wood (cellulose). Oxygen is released as part of the process. Through photosynthesis, a normal tree absorbs an average of 1 tonne carbon dioxide per cubic metre of growth, while at the same time producing and releasing the equivalent of 0.7 tonnes oxygen (see fig. 9).

The stored carbon is only released when the products are incinerated at the end of their life or when they rot down. The wood raw material and forest products are thus part of the green carbon cycle and add no further fossil carbon to the atmosphere – making them naturally climate neutral. Since the storage effect continues for as long as the wood product exists, using wood in large quantities for products with a long service life, such as building components, is particularly good for the climate. Wood’s carbon storage effect is currently not included in a building’s life cycle assessment (LCA), but it can be entered as a positive saving in module 4 (see table 5, page 19). To ensure a fair assessment, the wood’s carbon storage should therefore be included when conducting lifetime assessments of a building’s climate footprint, an issue that is expanded on in the section on Standards and Environmental Product Declarations.

Fig. 9  Wood is naturally climate neutral. Directly after felling, the cleared area leaks carbon dioxide as needles and discarded branches decay. Once the new trees reach a little over 20 years old, they are able to absorb more carbon dioxide than is leaking from the ground. The trees are harvested in maturity and then processed into products that are able to replace products and energy sources that are harmful to the climate. Making use of the forest is therefore good for the climate.

Photosynthesis, the world’s most vital formula.