AWA’s Ash Dieback Tree Risk Survey for Derbyshire County Council

This summer, AWA completed an extensive tree risk survey for Derbyshire County Council, focused on addressing the devastating impact of Ash Dieback disease across the region. This project, a vital component of the Council’s proactive Ash Dieback Action Plan, represents our ongoing work preserving the benefits of Ash trees provide while helping councils manage the risks associated with declining Ash trees.

Ash Dieback is a widespread and escalating threat, impacting up to 80% of ash trees in the UK and raising serious concerns for councils and landowners alike. With our expert guidance and cutting-edge assessment tools, AWA is equipped to support local councils and large landowners in mitigating risks, ensuring safe environments, and navigating the complexities of this growing liability.

The Growing Threat of Ash Dieback

Ash Dieback, caused by the fungal pathogen Hymenoscyphus fraxineus, has led to extensive decline in ash tree populations across Europe, with the UK among the hardest hit. Ash trees, integral to biodiversity, rural landscapes, and urban green spaces, are now facing unprecedented threats, creating significant safety and liability concerns for councils and landowners. Left unmanaged, ash trees weakened by the disease become prone to limb failure and collapse, with associated risk of harm to people and property, particularly in public areas, near roads, and on properties with high visitor traffic.

For councils, the implications are significant: the decline of ash trees affects not only the beauty and ecological balance of our green spaces but also increases the risk of harm from falling branches and tree failures. Recognising their responsibility, Derbyshire County Council prioritised a survey to assess the disease’s impact on ash trees in high-traffic areas, and AWA was grateful to partner with them to carry out this vital work.

AWA’s Approach: Comprehensive Tree Risk Assessment

Our tree risk survey for Derbyshire County Council is part of a phased approach, beginning with a previous assessment of primary highways and expanding this year to the Council’s broader estate. With a team of experienced arboricultural consultants, AWA assessed several thousand ash trees across around 450 sites, including schools, council properties, and adjacent lands. Utilising the Quantified Tree Risk Assessment (QTRA) system along with a detailed crown vitality model to categorize each tree’s condition and associated risks.

Key Aspects of the Survey Included:

GIS Data Collection: Using GIS mapping, we provided a comprehensive dataset that included site names, addresses, and ash tree locations. This enabled precise identification and prioritisation, maximizing efficiency in covering the Council’s extensive land portfolio.

Ground-Level Visual Assessment: Each tree was inspected through a detailed, ground-level visual assessment. This covered everything from species identification, height, and canopy spread to signs of dieback and decay, offering a thorough picture of the current risks.

Risk and Condition Classification: To accurately assess each tree’s condition, we utilized the Tree Council’s four-stage crown vitality model. This approach allowed us to categorize trees based on their remaining leaf cover, from 100%-75% in Stage 1 to 25%-0% in Stage 4, effectively identifying those most at risk of failure. With the Quantified Tree Risk Assessment methodology, we assigned each tree a quantitative risk rating, allowing us to measure the risk of tree failure in a systematic, industry-approved manner.

Precise Mapping and Photography: With grid references recorded for each tree, our survey data is not only accurate but also highly actionable. Additionally, high-quality photographs of each tree provided a visual record of conditions, supporting future monitoring and maintenance efforts.

Proactive Risk Management: How AWA Can Help

The completion of this survey for Derbyshire County Council is another example of AWA’s ability to deliver large-scale, high-quality tree risk assessments. For councils and large landowners, managing the risks associated with Ash Dieback requires specialised expertise, careful planning, and effective monitoring. That’s where AWA’s team of qualified arboricultural consultants comes in, offering services designed to help organizations manage their liabilities while protecting public safety and ecological value.

Our services include:

Baseline Risk Surveys and Mapping: We begin with a comprehensive survey to establish a clear understanding of tree locations, health conditions, and proximity to high-traffic areas. Using GIS and other advanced mapping tools, we ensure precise data collection for more efficient risk management.

Tree Health and Vitality Assessments: With our expertise in assessing Ash Dieback, AWA applies rigorous vitality models and risk assessment methodologies, such as QTRA and VALID, to ensure every tree is evaluated against industry-leading standards.

Specialist Decay Detection: Sometimes AWA’s advanced tree decay detection service proves invaluable. Using cutting-edge technology, including the PiCUS 3 sonic tomography , we assess suspected problems with high accuracy, allowing for informed tree management decisions.

Actionable Reporting and Recommendations: Our detailed reports provide clients with clear, actionable recommendations for each surveyed tree, from immediate interventions to ongoing monitoring. These insights help prioritize budgets, manage liability, and make data-driven decisions about tree management.

Ongoing Monitoring and Management Support: Ash Dieback is a progressive disease, and tree conditions can change quickly. We offer ongoing support to help councils and landowners maintain safe and sustainable landscapes, with regular monitoring and re-evaluation options as needed.

Planning for a Sustainable Future

AWA’s work with Derbyshire County Council is a powerful example of how councils and large landowners can proactively manage the effects of Ash Dieback. Beyond this project, we are dedicated to providing high-quality tree risk assessment services to organizations across the UK. By combining our arboricultural expertise with advanced technology and ecological sensitivity, we help safeguard public safety and support the health and resilience of our shared green spaces.

For councils and landowners navigating the challenges of Ash Dieback, AWA offers an experienced partner to guide you through effective, evidence-based risk management. Contact us today to learn how we can support your organization in addressing Ash Dieback and other tree risk challenges.