How renewable timber can lower the carbon footprint of your project

If you are taking on a construction project, it is smart to make sustainable choices. As the world’s resources dwindle and consumer demand for eco-friendly solutions is on the rise, choosing materials which have a positive impact on the environment is a no-brainer! One such material is timber. It is tried, tested and loved in the world of sustainable construction, especially for its embodied and sequestered carbon benefits, which could lower the carbon footprint of your entire project.

What is a Renewable Resource?

The definition of a renewable resource in the UK is, according to The British Standard, one which has been grown and naturally replenished on a human timescale. These are materials which could be exhausted, but with the right management can also last indefinitely. 

From a global perspective, between 1990 and 2010, we have seen a decrease in the area covered by forests. However, this is not actually the case in Europe and the UK. Here forest areas have been increasing, even as we have been using them to supply some of our timber! In fact, in this same time period (1990-2010), forested areas have grown by around 10% in the UK. 

One of the main reasons for this is that there has been a growing demand for timber in construction. As demand increases, so does our need to source it responsibly and thus maintain our world’s forests’ capacity. There are plenty of schemes to aid this process of responsible forest management, such as the FSC and the PEFC. These are two of the earliest promoters for responsible forestry and are still pioneering standards in the industry.

What is Embodied Carbon?

When we talk about embodied carbon, we are referring to the net carbon dioxide emissions released during the production, use and disposal of a product – in this case, timber. You will often see this as a measurement of CO2e. That little e stands for “equivalent”, and it means that all the greenhouse gases released are included, not just CO2

What is Sequestered Carbon?

Timber is a really interesting material in terms of its environmental impact because it can actually have a positive one, which is quite rare! The trees which create timber absorb, or sequester, carbon as they grow. This is then stored in the tree, including in the wood that one day could be used for your decking or cladding. If the tree is left to rot, the CO2e is released back into the atmosphere, with only a small part being retained in the soil.

What About Wood Used For Timber?

When a tree is turned into timber, it is not left to rot. This means that the sequestered carbon is stored for as long as the timber is used. 1kg of dried timber contains around 0.5kg of carbon. Thus every kg of timber used in construction represents 1.8kg of absorbed CO2e.

A small amount of this carbon is let back into the atmosphere during production and processing. During these processes, although more CO2e is released, it still usually is not more than the amount sequestered, giving a negative net embodied carbon for the timber you use.

End of Life and Disposal

The latest figures from 2011 show that only 60% of timber used for construction in the UK is either reused or recycled at the end of its life. The rest ends up in the landfill, which is not quite so eco-friendly. This is a lot less than other construction materials, though it is expected to increase because of the UK landfill tax escalator.

However, timber cannot be recycled easily in the traditional sense of the word  – which works to reprocess materials into a brand new product with the same characteristics. Nevertheless, it can be recycled into slightly lower grade products, such as animal bedding and wood particleboard.

Timber which has been taken to the landfill, on the other hand, will slowly decompose. As it does it gives off methane, an extremely powerful greenhouse gas. A small amount of this can be stored and used in energy production, but most of it will be released into the atmosphere. 

However, it is good to note that around 96% of the carbon stored in the timber is not converted into methane and released. Instead it moves into the soil as the wood decays and remains there, potentially locked away for thousands of years.

Other Indicators for Sustainability in Construction

Standards such as BS EN 15804 look at and consider any additional indicators which can be used to measure sustainability in construction. These include:

• Depletion of the ozone layer

• Energy, water and resource use

• Land and water pollution and acidification

• Eutrophication

The Environmental Product Declarations (EPD) data does not see any consistent environmental concerns for timber when looking at these indicators. The only area where sustainability does fall a little is in water use, which is usually high for timber because of the amount of rainwater needed to grow a tree. Though as it is rainwater and not treated water which is used, the impact is fairly low. 

The Global Carbon Cycle

Forests play a huge role in the world’s carbon cycle and are key in our fight against climate change. They are major and essential carbon sinks, absorbing CO2 from the atmosphere and storing it safely, helping to lower levels in the atmosphere. By increasing the forest area of the planet and using timber sourced from responsibly managed forests, you can invest in a method of carbon capture which is proven to help our planet. It is a strategy which can reduce the effects of our past carbon emissions, working towards a greener, safer future.

Choose Sustainable Timber With FSC

At EcoChoice, we know the value of sustainable timber, both for what it can bring to your project and what it can do for our planet. If you would like to learn more about this eco-friendly construction material, feel free to get in touch with our team today! We can also match your needs to the right timber species, ensuring your project has exactly what it needs to be a sustainable success. 

Image: sivivolk / Shutterstock.com