Steep ground harvesting and landslide prevention: the A82 project
This case study discusses the A82 project in Scotland, which aims to mitigate landslide risks along a major road running from Glasgow to Inverness, particularly through forested, steep slopes near Glen Coe. The forests, established in the early 20th century, now contain large, mature conifers that are increasingly vulnerable to windthrow, especially under changing climate conditions with more severe storms and rainfall. Such windthrow can destabilize slopes, increasing the threat of landslides and rockfalls that pose risks to public safety, infrastructure, and the economy.
The management objectives focus on reducing these risks by removing large conifers and replacing them with slow-growing broadleaved species that can better stabilize slopes and enhance biodiversity by creating connected woodland corridors. They employ tools like ForestGALES and ESC to assess wind risk and species suitability under future climate scenarios. The project involves small-scale trials from 2007–8, followed by large-scale operations planned over up to 20 years, with annual costs around £1 million. Harvesting is complex, requiring specialist equipment like skyline winches and skilled operators, and sometimes involves hauling trees long distances uphill. Safety measures include installing rock catch fences, nets, anchors, gabions, and traffic controls to protect the public and infrastructure during operations.
Monitoring and assessment are integral to the project, focusing on high-risk areas for timely intervention, supported by a partnership approach among agencies such as Transport Scotland, Highland Council, and Police Scotland. The project emphasizes learning through experience, collaboration, and research partnerships to improve skills and management strategies. The ultimate goal is to establish a contiguous broadleaf woodland that stabilizes slopes, reduces reliance on extensive engineering, and provides long-term resilience against climate change impacts. This case study highlights integrated, adaptive management approaches crucial for managing steep, forested terrain to protect transportation infrastructure and promote ecological benefits.
[https://cdn.forestresearch.gov.uk/2023/11/Steep-ground-harvesting-and-landslide-prevention-the-A82-Project.pdf Steep ground harvesting and landslide
prevention: the A82 project] (en)
Number of pages: 3
Target countries: Scotland
Key takeaways
- Replacing mature conifers with broadleaved species enhances slope stability and resilience
- The primary management objective is to develop a continuous broadleaf woodland corridor that stabilizes slopes and provides biodiversity benefits, reducing the need for extensive future interventions.
- Climate change increases landslide and windthrow risks, necessitating adaptive management
- Projections of more severe storms, winter rainfall, drought, wildfire, and pests highlight the importance of selecting species and management practices that enhance forest resilience to climate impacts on steep slopes.
- Use of decision support tools like ForestGALES and ESC informs species selection and risk assessment
- These tools assist in evaluating wind risk and identifying appropriate species to ensure slope stability and future climate adaptability, making management decisions more targeted and effective.
- Steep ground harvesting requires specialist techniques and infrastructure, increasing complexity and costs
- Harvesting on difficult terrain involves equipment like skyline winches and skilled operators, and sometimes building new infrastructure, with an annual cost of around £1 million for felling and engineering works.
- Protective measures such as rock catch fences and traffic controls are essential for public safety during operations
- To mitigate rockfall and debris risk, geotechnical safeguards and traffic management are employed, ensuring safety for the public, road users, utilities, and workers.
- Monitoring and adaptive management are integral, but expensive, components of the project
- Ongoing assessment of high-risk areas and partnership collaboration enable informed planning while spreading costs, crucial for long-term slope stability and safety.
- Long-term outcomes aim for a resilient, mixed broadleaf forest with reduced dependence on hard engineering measures
- The project emphasizes creating contiguous, biodiverse woodland that supports slope stability, enhances ecosystem resilience, and builds expertise within the forestry sector for difficult terrain management.
Sources
- Steep ground harvesting and landslide
prevention: the A82 project - - https://cdn.forestresearch.gov.uk/2023/11/Steep-ground-harvesting-and-landslide-prevention-the-A82-Project.pdf
