Overview of Holnicote Estate
Holnicote Estate, nestled within the stunning Exmoor National Park in West Somerset, encompasses an impressive 5,059 hectares, of which 600 hectares are designated as woodland. This area is accessible land under the Countryside and Rights of Way Act (2000), featuring an extensive network of 150 miles of public footpaths and bridleways. The estate, managed by the National Trust, showcases a varied landscape that includes the rugged moorland of Dunkery Hill, the picturesque shingle beaches of Selworthy and Bossington, as well as numerous woodland habitats.
Among these habitats lies the Horner Wood National Nature Reserve, a Site of Special Scientific Interest, which protects 351.8 hectares of ancient oak woodland. This diverse ecosystem is not only essential for wildlife but also plays a crucial role in nature conservation efforts across the region.
Challenges Posed by Grey Squirrels
One of the primary threats to the woodland habitats at Holnicote Estate is the grey squirrel population. These invasive mammals are known for stripping bark from trees, both young and old, particularly affecting the tree canopy. In severe cases, they can remove as much as 60-70% of the bark, leading to weakened trees that are more susceptible to wind damage.
The introduction of pine martens on the estate has further complicated the management of grey squirrels. Since the presence of these native predators has been confirmed, the use of lethal traps for controlling grey squirrels has been restricted to safeguard the pine martens. Consequently, alternative methods such as live trapping have proven impractical due to the estate’s vast size and the resources required for effective implementation.
To combat this issue, Holnicote Estate collaborates with neighbouring landowners as part of a comprehensive grey squirrel control initiative within Exmoor National Park. A trained group of volunteers has been established to utilise low-powered air rifles for culling grey squirrels at designated bait stations. From October 2024 to June 2025, this effort successfully removed around 150 grey squirrels from areas previously suffering extensive damage, all while prioritising public safety.
Innovative Approaches to Tree Protection
While traditional deer fencing is a common method for safeguarding young trees, Holnicote Estate has opted for a more adaptive strategy after considering the downsides of fencing, including its maintenance and the potential to merely displace deer to surrounding areas. The financial implications were also significant, as the cost of fencing the 17-hectare Riverlands Wood at Porlock Vale equated to employing a full-time Wildlife Manager for a year, prompting a re-evaluation of priorities.
Instead of committing to expensive fencing solutions, the estate has embraced a flexible strategy supported by government grants that fund targeted deer and squirrel control efforts. This approach, combined with the overplanting of specific tree species, has allowed for a reduced reliance on protective measures such as guards and fencing.
Managing Deer Populations Effectively
While red deer contribute significantly to the local tourism industry, the presence of browsing roe deer poses a threat to the growth of young trees and coppice regeneration, especially in areas inhabited by Eurasian beavers. To mitigate this risk, the estate applies Trico®, a deer repellent derived from emulsified sheep fat, in Riverlands Wood, where conventional fencing and tree guards would be prohibitively costly.
This repellent is manually applied to each tree twice a year, once in early spring and again in autumn. Early observations suggest that this method has been highly effective, reducing deer browsing damage to below 20% within the first year of application. However, the success may also be influenced by the strategic overstocking of trees in the woodland.
Furthermore, to bolster deer management, the estate maintains glades and rides featuring highly palatable flora along woodland edges, providing alternative browsing habitats. Historically, these areas comprised a small fraction of the woodland, but now they are integrated into all management plans, with deer management as a primary consideration. This strategy has also enhanced the biodiversity of these regions.
Holistic Management Strategies for Sustainable Woodlands
Lethal control measures are selectively implemented to ensure that deer populations remain healthy and sustainable, currently estimated at around eight deer per square kilometre. Simon Powne, a Wildlife Biologist with the National Trust, emphasises the importance of a balanced approach that incorporates habitat management, tree species selection, and both non-lethal and lethal management strategies. He notes, “It’s crucial to define your objectives for the woodland, determine the level of damage you can tolerate, and consider the goals for wildlife as well.”
Further Resources for Woodland Management
For those seeking additional insights into woodland management and related topics, several resources are available:
- National Trust – Offers extensive information about Holnicote Estate.
- Confederation of Forest Industries – Provides a two-year review of Trico® as a deer repellent.
- Scottish Forestry – Features a woodland herbivore impact assessment to evaluate deer damage to trees.
- Forest Research – Discusses the ‘nearest neighbour’ method for quantifying wildlife damage to trees.
- Visual Guide to Grey Squirrel and Deer Damage – A practical guide for identifying damage caused by these animals.