As we wrap up the Tree Roots and Archaeology project with the publication of the report today, it’s an opportune moment to reflect on the journey we’ve taken and the significant insights we’ve gathered along the way. When we first embarked on this project, the goal was to collect existing literature and supplement it with evidence from the experience of heritage and forestry professionals. This was a complex task, as this subject is surrounded by many, sometimes conflicting, views and practice is often based on patchy evidence. 

As the UK strives to increase its tree cover to mitigate the effects of climate change and address the loss of biodiversity, the Forestry Commission, with support from the Nature for Climate Fund, promoted new research into the subject to ensure that future guidelines are based on up-to-date and comprehensive evidence. 

The Journey Begins

At the start of this project, we recognized that tree roots are often viewed with caution when it comes to archaeology. The prevailing narrative, shaped by decades of anecdotal evidence and worst-case scenarios, suggested that tree roots were a persistent threat to heritage assets. These concerns were especially pronounced in areas with unknown archaeological features or where traditional woodland management practices, like the use of heavy machinery, exacerbated the problem.

Our aim was to dig deeper—quite literally—into these assumptions and to bring a more balanced perspective to the table. We wanted to understand not just the risks but also the potential benefits that trees and their roots could offer to archaeological sites.

After a comprehensive review of existing literature on the subject, we first reached out to professionals in both sectors through a questionnaire to collect their views and experiences. We then interviewed foresters, archaeologists and heritage professionals to explore the interactions between tree roots, management practices and archaeology in more depth.

Findings and Recommendations

The results of our research and stakeholder engagement are an illustrated report with recommendations for further research and field investigations. The report confirms that there are many different aspects that determine the impact of tree roots on archaeology (soil, tree species, type of archaeological features and finds etc.), but also that there’s room for a more nuanced understanding.

Here are some of the key recommendations that emerged from our study:

Urgent Need for Further Research: While tree roots have been shown to have both positive and negative impacts on heritage assets, there is an urgent need for more field-based research. The current approaches to tree planting in archaeologically sensitive areas are often based on anecdotal evidence, particularly from cases where tree roots have caused significant damage. This has led to a fragmented understanding, which makes it difficult to develop consistent policies.

Reassessing Historical Perceptions: Many heritage professionals’ negative perceptions of tree roots are rooted in historical concerns, often related to unknown archaeology or secondary impacts of woodland management. These views have persisted partly due to a lack of detailed empirical research. Our findings suggest that it’s time to reassess these perceptions in light of new evidence.

Strategic Tree Planting: Our research shows that with the right combination of deep- and shallow-rooted species, tree planting can actually benefit archaeological sites. Strategic planting can help stabilize slopes, prevent soil erosion, and even curb more damaging land use activities, like deep ploughing. In several instances, woodland cover has acted as a long-term protector of archaeological monuments. The principle of “the right tree in the right place for the right reasons” applies to the interaction with archaeology and heritage sites as well. 

Enhancing Visitor Experience: Woodland settings can greatly enhance the public’s experience of archaeological sites. Incorporating known archaeological sites within planting schemes can improve public access and engagement, making these sites more accessible and enjoyable for visitors.

Protecting the Unknown: While planting and woodland management can protect known archaeological remains, they are less effective in safeguarding areas with un-surveyed archaeology. This highlights the need for continued survey and research efforts before implementing new planting schemes.

Improving Collaboration: The project underscored the need for better collaboration between heritage and forestry professionals. Improved communication, greater consultation, and shared management practices will be crucial in addressing concerns and ensuring that both heritage and forestry interests are adequately represented.

Adopting New Methods: Finally, the report notes that approaches to tree planting in archaeologically sensitive areas are already evolving. New ‘sensitivity mapping’ methods are being developed, which will help practitioners identify archaeological features and assess their significance. Choosing the right sites and the right tree species will be key to making progress in this area.

Looking Forward

The conclusion of this project marks significant progress in our understanding of the impact of tree roots on archaeology. While there is still much to learn, the insights gained from this study lay a strong foundation for future work. We are grateful to the Forestry Commission and the Nature for Climate Fund for making this important research possible. 

And we are very grateful for the opportunity, through this project, to gain a better understanding how professional archaeology can support the forestry sector with its efforts to deliver afforestation and nature recovery that benefit the whole of society. As Oxford Archaeology Project Manager Carl Champness commented "Everyone has a role to play in helping combat climate change. The tree roots project addresses some of the critical issues of how new tree planting could impact archaeological remains. This initial study helps summarise the current available research data, challenges some of the preconceptions surrounding the impacts of tree roots on archaeology, and highlights a way forward for future field study.  By investing in future research, we can provide a baseline to help inform future planting schemes and learn from the lessons of the past."

We hope that the report’s findings will not only influence policy and practice but also encourage more research and collaboration in this vital area. As we look to the future, it’s clear that a balanced approach — one that recognizes both the risks and the benefits of trees in archaeological contexts — will be essential. We are excited about the possibilities that lie ahead and look forward to continuing this important work in collaboration with our partners across the heritage and forestry sectors.

Thank you to everyone who has been a part of this journey, and we look forward to what the future holds.

The Assessing the Impact of Tree Roots report is now available for download on the OA's Knowledge Hub.