Why is construction chasing net zero while ignoring the carbon we are destroying?

The UK construction industry is under intense pressure to reduce carbon emissions. From embodied carbon calculations to material innovation and net zero targets, the focus is clear - build better, build cleaner and build more sustainably, but there is a glaring contradiction at the heart of this ambition. While we invest time, money and policy into reducing carbon, we continue to remove one of the most effective natural carbon stores we have – tens of thousands of trees and established hedgerows - often without properly measuring the impact, writes Aaron Morley at Ruskins, the tree and soil specialists.

According to the Woodland Trust, UK trees and woodlands store around 18 million tonnes of CO₂ every year. That is a significant contribution to national carbon reduction efforts, but when development takes place, particularly across housing and highways schemes, these assets are frequently removed as a matter of routine.

The carbon they store and their future capacity to absorb more, is effectively wiped out overnight. Crucially, this loss is rarely factored into project-level carbon reporting in any meaningful way.

One of the most uncomfortable truths is that we do not have a national figure for how many trees and hedgerows are lost each year due to construction and housebuilding. There is no centralised dataset. Losses are recorded locally, inconsistently and rarely brought together. At the same time, however, the industry is encouraged to report on tree planting and biodiversity net gain. This creates a distorted picture, because we only measure what we add and not what we remove.

Replacement is not equivalent

The standard response to tree removal is mitigation through planting, but the evidence suggests this approach is fundamentally flawed. Research highlighted by the University of Sheffield found that 39% of trees planted on new housing developments were dead or missing, while 48% of hedgerows expected to be delivered had not been installed. This is not a marginal issue. It is systemic.

Even where planting does succeed, a sapling cannot replace the environmental value of a large tree for decades. In carbon terms, the loss is immediate, while the benefit of replacement is delayed, often by a generation.

While trees receive attention, hedgerows are often overlooked, even though they are vital carbon stores and biodiversity corridors. According to the Tree Council, the UK has already lost around half of its hedgerows since World War II, with development playing a significant role.

Despite this, they are still routinely removed during construction, frequently without meaningful or successful replacement. This is a quiet, but significant environmental loss and one that is rarely discussed.

Nowhere is this contradiction more visible than in major infrastructure schemes. The A14 Cambridge to Huntingdon improvement saw the removal of over 500,000 trees, with reports suggesting that up to 90% of replacement planting failed to establish itself as reported by the Energy Management Summit in 2023.

This is not an isolated case. It reflects a wider pattern across construction where large-scale removal is followed by uncertain replacement outcomes – and here is the irony. At the same time, these projects are often presented as contributing to sustainability and economic growth.

There is another way and it already exists

If construction cannot plan works to retain large trees, there are alternatives that are available. The relocation of large trees and established hedgerows is not a new concept. It is an established and proven process used in both the UK and internationally.

With early planning and the right expertise, trees can be carefully lifted, moved and successfully re-established. This preserves their carbon value, maintains biodiversity and avoids the long-term environmental gap created by removal.

In many cases, it is entirely achievable. The issue is not whether it can be done. It is whether it is considered early enough in the design and planning process.

The current approach reflects a deeper issue within construction. Carbon reduction strategies tend to focus on materials, transport and energy use, all of which are important, but natural assets are often treated as secondary considerations.

Trees and hedgerows are seen as obstacles to be managed, rather than assets to be preserved. But from a carbon perspective, retaining a mature tree can deliver an immediate and measurable benefit, often far greater than marginal gains elsewhere in a project.

All this means that if the construction industry is serious about net zero, it needs to confront a simple, but uncomfortable question. Why are we working so hard to reduce carbon emissions, while simultaneously removing large volumes of stored carbon through the loss of large trees and hedgerows? And why are we not properly measuring it?

A call for change

This is not about stopping development. It is about delivering it differently.

It means:

• Measuring tree and hedgerow loss at a national level
• Accounting for carbon loss in project reporting
• Prioritising retention in design
• Considering relocation as a standard option, not an exception
• Ensuring that where planting does take place, it is supported by healthy soil and long-term management

These are practical steps. They are achievable and they align directly with the industry’s wider environmental commitments.

We are not short of ambition in construction. The drive towards net zero is real, but ambition without full accountability is not enough. Because until we recognise the true carbon cost of removing mature trees and hedgerows and act to reduce it, we will continue to undermine our own progress.

Because the most effective carbon saving on any project might not come from what we build. It might come from what we choose not to remove.

Frequently Asked Questions

1. Why are mature trees important for reducing carbon emissions?

Mature trees are one of the UK's most effective natural carbon stores. They absorb carbon dioxide throughout their lifetime and store significant amounts of carbon in their trunks, branches, roots and surrounding soil. Retaining mature trees can often deliver greater immediate carbon benefits than planting large numbers of new saplings.

2. What is the carbon impact of removing mature trees during construction?

Removing mature trees releases stored carbon over time and eliminates their future ability to absorb carbon dioxide. While replacement planting can help, it may take decades before young trees provide the same environmental and carbon storage benefits as the trees they replace.

3. Can mature trees be relocated instead of being felled?

Yes. With careful planning, specialist equipment and experienced arboricultural contractors, many mature trees can be successfully relocated. Tree relocation allows valuable landscape assets to be retained while supporting development and preserving existing carbon storage.

4. Why are hedgerows important for biodiversity and climate change?

Hedgerows provide essential habitats for wildlife, act as ecological corridors, reduce soil erosion, improve water management and store carbon. They are a vital part of the UK's natural infrastructure and play an important role in achieving biodiversity and climate objectives.

5. What is Biodiversity Net Gain (BNG)?

Biodiversity Net Gain is a planning requirement that aims to leave biodiversity in a measurably better state after development than before. Developers must demonstrate at least a 10% net gain for most projects in England, making habitat retention and enhancement increasingly important.

6. Is planting new trees enough to replace mature trees?

Not always. Newly planted trees require many years, and often decades, to reach the size and environmental value of mature specimens. They also require suitable soil conditions, maintenance and ongoing management to survive and deliver their intended benefits.

7. Why should tree retention be considered early in the design process?

Early planning provides greater flexibility to protect or relocate valuable trees before site layouts are finalised. Considering tree retention during the concept and planning stages often reduces environmental impacts, lowers costs and improves project sustainability.

8. How does healthy soil support successful tree planting?

Healthy soil provides the nutrients, drainage, structure and biological activity that trees need to establish strong root systems. Without appropriate soil management, newly planted trees are more likely to fail, reducing the environmental benefits expected from replacement planting.

9. How do trees contribute to sustainable construction?

Trees improve air quality, reduce urban heat island effects, capture carbon, support biodiversity, manage surface water and enhance the wellbeing of local communities. Protecting existing trees is an important part of creating more sustainable developments.

10. Why should carbon from tree removal be included in project carbon assessments?

Current carbon reporting often focuses on embodied carbon in materials and operational emissions while overlooking the carbon stored in mature trees and hedgerows. Including natural carbon losses would provide a more accurate assessment of a development's overall environmental impact.

11. What is the difference between tree protection and tree relocation?

Tree protection involves safeguarding existing trees so they remain in their original location throughout construction. Tree relocation involves carefully lifting and transplanting trees to another suitable location on or near the development site when retention in situ is not possible.

12. How can developers reduce the environmental impact of site clearance?

Developers can minimise environmental impact by surveying trees early, retaining mature specimens wherever possible, relocating valuable trees and hedgerows, protecting healthy soils, incorporating green infrastructure into designs and adopting a whole-life approach to carbon and biodiversity management.