C2. Mitigation Strategy for the Chilterns Beechwoods SAC at Ashridge Commons and Woods SSSI

The Chilterns Beechwoods SAC is an extensive area of native beech woodland covering approximately 1,276.5 ha across multiple component Site of Special Scientific Interest (SSSI) designations, including Ashridge Commons and Woods SSSI. The SAC supports listed habitats such as beech forests on neutral to rich soils and semi‑natural dry grasslands, as well as species including the stag beetle (Lucanus cervus).

Ashridge Commons and Woods SSSI, the principal site for this mitigation strategy, is highly accessible to the public and attracts significant visitor numbers due to its mix of woodland recreation, historic landscape features and accessibility from surrounding communities. The strategy identifies recreational pressure, particularly from footpath use and associated disturbance, as a principal pathway through which new development could adversely affect the SAC.

The Mitigation Strategy for the Ashridge Commons and Woods SSSI component of the Chilterns Beechwoods SAC functions as an operational framework for multiple authorities within the SAC’s Zone of Influence (ZoI) (12.6 km). 

Policies NE4, NE5 and NE6 of the Dacorum Local Plan to 2041 secure mitigation at this component of the SAC.  The Dacorum Local Plan was submitted to the Secretary of State for Independent Examination on 11 March 2025.

The Chilterns Beechwoods SAC Mitigation Strategy sets out a consistent approach for planning authorities to screen, assess, and determine planning applications likely to affect the Ashridge Commons and Woods SSSI component of the SAC, and defines how mitigation contributions, in the form of SAMM and SANGs, should be provided, either through bespoke arrangements or strategic solutions.  The Strategy functions by translating high-level obligations into practical mitigation measures and is a two‑part document:

• Part A provides broad guidance to all LPAs within the ZoI, including screening and appropriate assessment processes, buffer zone considerations, and mitigation principles. 
• Part B provides detailed guidance (in this instance specifically for Dacorum Borough Council) on how mitigation (SAMM and SANG) should be secured, administered, and delivered through planning obligations.

The Strategy sets out a cross-authority framework for understanding the SAC’s ZoI and the types of mitigation required for residential developments. The 12.6 km ZoI captures developments likely to generate recreational pressure, and screening and mitigation are required for all qualifying residential proposals. It also provides guidance through the designation of a 500 m avoidance zone around Ashridge Commons and Woods SSSI, where there is a presumption against development due to habitat sensitivity. 

• Evidence led

The mitigation strategy is underpinned by a robust evidence base relating to visitor pressure, recreation patterns, and ecological sensitivities affecting the Chilterns Beechwoods SAC at the Ashridge Commons and Woods SSSI component. Visitor surveys, ecological studies, and Habitats Regulations Assessment work have informed the defined 12.6km ZoI, 500m Avoidance Zone and associated mitigation requirements. This evidence-led approach ensures that mitigation measures are proportionate, justified, and clearly linked to the identified recreational disturbance impact pathway rather than being arbitrary or overly precautionary.

• Clear messaging

A key strength of the mitigation strategy is the clarity of the guidance provided to applicants and decision makers.  The structure of the document into two clear parts, Part A and Part B, allows roll out of the strategy to multiple LPA areas in a consistent manner.  Part A ensures the implementation of strategic information relevant to all LPAs. While Part B allows locally specific details to be communicated on a LPA by LPA basis. 

Parts A and B are both clearly organised and provide developers with information on the background context to the Strategy and drivers for mitigation requirements.  In addition, detailed information is provided on the types of development and applications affected, financial contributions, methods for securing mitigation, detailed SANG information (including design requirements and the process for allocation of strategic SANG) and exceptions. This depth of information ensures all parties are clear on the process for delivery of an appropriate level of mitigation for the SAC.

• Use of spatial zones

The strategy uses a clearly defined ZoI (12.6km) around the SAC of within which residential development is required to contribute towards mitigation measures and a 500m Avoidance Area where there is a presumption against development. The use of mapped spatial zones linked to specific mitigation requirements provides clarity and consistency in decision-making and reduces the need for case-by-case assessment of recreational impacts. This spatial approach reflects visitor travel patterns and therefore ensures mitigation is targeted at development that is most likely to generate recreational pressure on the protected site.

• Detailed information on delivery

The mitigation strategy provides detailed information on how mitigation will be delivered, including financial contributions, SAMMs, and detailed guidance on the quality, requirements and delivery of SANG. Financial contributions are standardised and calculated on a per-dwelling basis, ensuring transparency and consistency across developments. Contributions are secured through planning obligations, ensuring mitigation is funded and delivered in line with development. The strategy also sets out how mitigation measures will be implemented, managed, and maintained over the long term, which strengthens the deliverability of the approach.

• Strategic approach to mitigation

A key strength of the strategy is that it adopts a strategic mitigation approach rather than relying on individual developments to provide separate mitigation. SAMM, together with the provision and enhancement of alternative green spaces (SANG and Gateway sites), help reduce recreational pressure on the SAC at a landscape scale. This strategic approach is more effective, more efficient, and more deliverable than piecemeal mitigation provided on a site-by-site basis.

• Partnership working

The mitigation strategy has been prepared in consultation with key stakeholders, including Natural England and the National Trust, ensuring that the approach is ecologically appropriate and compliant with the Habitats Regulations. Partnership working is particularly important for protected sites that are affected by development across multiple administrative areas and helps ensure that mitigation measures are coordinated and effective.

• Monitoring and adaptive management

The strategy includes monitoring and review mechanisms to assess the effectiveness of mitigation measures over time. Monitoring visitor numbers, access patterns, and ecological indicators allows the Council and its partners to review whether mitigation is working and adjust measures if necessary. This adaptive management approach ensures that the mitigation strategy remains effective over the long term and can respond to changes in development levels, visitor behaviour, or environmental conditions.