Carbon
Trees grow and gain energy using photosynthesis, where carbon dioxide is absorbed and broken down to create energy. The carbon is stored in the wood, and the oxygen is released back into the atmosphere. This means when you build with timber, you are building with carbon.
In a world seeking to decarbonise the atmosphere, timber is an essential building material. This is because it has a reduced carbon emissions profile when compared with traditional building materials such as concrete and steel. This page explores the relationship between carbon, timber and the built environment with extracts from our knowledge library – outlining the key concepts you should understand.
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Explained
The carbon cycle is fundamental to sustaining life on Earth. Through natural processes such as photosynthesis, respiration, decomposition, and fossilisation, carbon moves continuously between the atmosphere, oceans, living organisms, and geologic reservoirs. Among these carbon pools, organic matter — including trees and timber — play a crucial role in sequestering carbon from the atmosphere.
Human activities, particularly over the last 200 years, have increasingly disrupted this natural equilibrium. The use of fossil fuels, along with land-use changes like deforestation and urban expansion, has introduced vast quantities of carbon dioxide (CO₂) into the atmosphere. These new forms of carbon emissions overwhelm the Earth’s natural ability to reabsorb it, contributing significantly to global warming and climate change.
Carbon Cycle and Storage. To sustain life on earth, the carbon cycle must maintain an equilibrium.
However, trees remain among our most effective carbon sinks. During photosynthesis, they absorb atmospheric CO₂ and convert it into biomass, storing carbon in the form of cellulose, lignin, and starch within trunks, branches, and roots. When trees are harvested and converted into timber, this stored carbon can remain locked in for decades, or even centuries — particularly when the wood is used in long-life construction products such as beams, floors, and other structural components.
This ability to store carbon makes timber an important material in climate-conscious construction. Unlike high-embodied carbon materials such as concrete and steel, timber not only requires less energy to produce but also contributes to net carbon storage when sourced responsibly. In this context, the use of timber in the built environment can be viewed as a form of natural carbon capture and storage (CCS).
The use of sustainable forest management practices ensure that timber harvesting is balanced with replanting. Forests which are actively managed - with several new trees planted for each one harvested - can help restore the carbon cycle. Young trees, in their fast-growing phases, tend to absorb carbon more rapidly, however CO₂ absorption reduces the older the tress gets. Timber products continue to store the carbon absorbed during their growth throughout the products life. This approach creates a dynamic carbon sink, with forests and buildings working together to mitigate climate change.
Timber Policy. This document explores the regulatory instruments used by countries around the world to reduce carbon emissions.
As much as half of the UK’s territorial carbon emissions can be attributed to the construction, operation, and maintenance of the built environment. Broadly, its carbon impact is composed of two key elements:
- Embodied Carbon – Emissions associated with the manufacture, transport, installation, maintenance, and end-of-life disposal of building materials.
- Operational Carbon – Emissions from the day-to-day energy use of a building, including electricity, heating, hot water, and other services.
Under UK law and numerous professional commitments, such as RIBA 2050, both forms of carbon emissions must be reduced to net zero by 2050.
While operational carbon is increasingly regulated - through mechanisms such as Building Regulations (e.g. Approved Document L) and aided by energy-efficient design and the decarbonisation of the national grid - embodied carbon remains largely unregulated. As a result, embodied carbon now makes up a growing proportion of the total life cycle emissions of buildings.
However, there is a growing movement to address embodied carbon. Tools like Environmental Product Declarations (EPDs) are improving transparency around material impacts, and called for legislation such as Part Z aims to bring embodied carbon under regulatory control.
Timber, with its significantly lower embodied carbon than materials like cement and steel, is increasingly recognised as a key strategy in reducing the built environment’s overall emissions.
Sustainably grown and harvested timber has a significantly lower carbon footprint than many other construction materials. As a result, buildings that use timber as a primary structural material can achieve lower embodied carbon levels compared to those constructed with materials such as concrete or steel.
Timber and Embodied Carbon. Learn the crucial concepts which inform the carbon profile of timber.
The reason timber’s embodied carbon is comparatively low lies in its natural growth process and the efficiency of its harvesting and manufacturing. Timber is a renewable resource that can be sustainably managed, and it requires relatively low energy inputs to process into construction products.
In many cases, sawmills are powered by bioenergy, using parts of the tree—such as bark, offcuts, or sawdust—that cannot be converted into long-life products. This closed-loop energy system further reduces the carbon intensity of timber production.
The UK timber supply chain is committed to achieving net zero carbon emissions by 2050. This ambition is detailed in The Timber Industry Net Zero Roadmap, published by Timber Development UK and endorsed across the sector. The roadmap outlines both current emission sources and key opportunities for decarbonisation.
Across the lifecycle of timber products, transportation often represents the largest share of emissions. This is in sharp contrast to materials such as cement, where the extraction of limestone, energy-intensive processing, and the release of CO₂ during calcination are inherently high-carbon activities.
While timber is not a universal solution for all building applications, its responsible and strategic use offers one of the most effective ways to reduce embodied carbon in construction — particularly in low- to mid-rise buildings, schools, housing, and extensions.
The UK timber industry is responsible for approximately 1.58 million tonnes of CO₂e in territorial emissions, representing just 0.35% of total UK emissions. In addition, imported embodied emissions - from the processing and transportation of wood products in their country of origin - add a further 4.16 million tonnes of CO₂e.
Net Zero Roadmap. This project establishes a clear route to net-zero carbon by 2050 for the industry.
Although these figures are significantly lower than emissions from other manufacturing sectors - for example, UK steel production accounts for 12 million tonnes CO₂e (2.7% of UK emissions) and UK concrete production for 7.3 million tonnes CO₂e (1.5%) - the timber sector recognises its responsibility and is actively working to reduce its environmental impact.
The most substantial emission sources requiring focused action are:
- Transport (both on-road and off-road), and
- Process heat used in manufacturing,
Transport emissions, particularly those from road freight, represent the single largest contributor - accounting for 55% of the industry’s total emissions. As such, the decarbonisation of Heavy Goods Vehicles (HGVs) is a critical enabler for reducing the industry’s overall carbon footprint.
While large, long-haul HGVs are currently difficult to decarbonise due to their high energy demands and long duty cycles, zero-emission HGV technologies are beginning to emerge, and early trials are already underway within the sector for shorter-haul applications.
Beyond transport, the industry continues to unlock carbon savings through more efficient manufacturing, particularly in sawmills and panel production. Improved kiln drying technologies and energy efficiency upgrades are helping reduce emissions at the production stage.
More information about the timber industry’s carbon profile, reduction strategies, and long-term goals can be found in the UK Timber Industry Net Zero Roadmap, produced by Timber Development UK and endorsed by the wider sector.
Reducing embodied carbon in buildings begins at the design stage. The decisions made during early planning - around materials, structure, form, and specification - have a profound impact on the total carbon footprint of a project across its lifecycle.
2025 Embodied Carbon Data for Timber Products. This is an essential tool for early stage design to allow for accurate emission estimations.
Timber, as a renewable and low-carbon material, plays a central role in designing for reduced embodied emissions. However, its effectiveness depends on how it is selected, sourced, and used. To fully realise timber’s potential as a climate-positive material, designers should aim to:
- Prioritise structural efficiency: Design efficient timber structures to minimise material waste while maintaining performance.
- Maximise carbon storage through long-life applications: Timber used in long-term structural and interior elements - such as beams, floors, and walls - stores biogenic carbon for the life of the building.
- Design for reuse and disassembly: Timber lends itself well to modular, demountable construction. Designing buildings so timber elements can be dismantled and reused in the future supports a circular economy and significantly reduces lifecycle emissions.
- Substitute high-carbon materials: Engineered products such as cross-laminated timber (CLT), glulam, and laminated veneer lumber (LVL) offer structural versatility and can displace high-carbon materials like steel or concrete in many building types.
Designing with timber is not only about selecting a low-carbon material - it’s about designing systems that are resource-efficient, durable, and future-ready. By integrating these principles, architects and engineers can lead the transition toward a more sustainable built environment.
One of the key tools all designers should understand, to help inform their material selection is Environmental Product Declarations. Timber Development UK produces weighted averaged EPD data for common timber products to aid design decisions.
Featured Resources
Embodied Carbon Data for Timber Products
Carbon Cycle and Storage
Timber and Embodied Carbon
Related Resources
Setra Wood Products – Sustainability Study
Optoppen – building upwards with timber
U-Build – a DIY modular building system
UPM Timber and Plywood Sustainability Study
The zero-emissions resource pool: construction materials compatible with a realistic view of delivering zero-emissions in the UK by 2050
Timber In Construction Manifesto
Whole-life embodied carbon in multistorey buildings: steel, concrete and timber structures
Net Zero Action plan tracker
Net Zero Strategy template
Carbon Calculator
Net Zero Roadmap
MP letter template – Support Jerome Mayhew MP’s embodied carbon bill
Abimci’s Study Sectoral 2022
Assessing the Carbon-Related Impacts and Benefits of Timber in Construction
Wood – Building the Bioeconomy
Growing Our Low-Carbon Future – Time For Timber
Case Studies
Training
USEFUL EXTERNAL LINKS
- RICS Whole life carbon assessment (WLCA) for the built environment: Measure whole-life carbon emissions, manage carbon budgets, reduce life cycle emissions.
- Pilot Version | UK Net Zero Carbon Buildings Standard: Prove your built assets are net zero carbon and in line with our nation’s climate target
- Climate Change Committee | Wood in Construction in the UK: Learn about the carbon impact of building with wood in the UK.
- ARUP | The time value of carbon: An introductory exploration on carbon emissions to support better decision making.
- Future Homes Hub UK: Free tool to help businesses across the sector share and report whole life carbon assessments on a consistent basis.