Ipsden BNG Habitat Enhancement

Challenge

Underground Gas Services:

• Careful planning was essential due to the presence of underground gas services across the site. All activities were designed to avoid disturbance to this critical infrastructure, ensuring both site safety and the integrity of underground utilities throughout the works.

Biodiversity Enhancement:

• The existing plantations had dense canopy cover, limiting light penetration to the forest floor and reducing understory vegetation that could support a variety of species. In addition, the lack of age structure and dense planting regime meant that the plantations lacked natural features like standing and fallen deadwood, open glades and roosting and nesting opportunities which are critical for many species.

  In line with our Biodiversity Net Gain (BNG) recommendations, we implemented a series of measures to enhance site biodiversity. These included:

  • Creating rides and glades to improve structural diversity and light availability.

  • Tree management works such as targeted felling, coppicing, and pollarding to introduce age variation and ecological niches.

  • Installation of artificial features, including species-specific nesting boxes, hibernacula, and a barn owl box to support a wider range of fauna.

Removal and Use of Felled Woody Material:

• With 20% of the woodland plantation being felled or coppiced there was a large amount of woody material that needed to be processed. In consultation with the client and the Keystone Ecology team it was decided to create dead hedges alongside the rides and glades.

Approach

Location of services:

• Working with the client we identified the location of the underground services, with crossing points created using ground protection and offsets marked out using barrier tape.

Creating Rides and Glades:

• A network of rides and glades was carefully planned with 20% of trees to be removed to open areas of the woodland to more light.

Coppicing, Pollarding and Pruning:

• Several trees overhanging the central compound were coppiced, pollarded or pruned to reduce the likelihood of branch fall into the utilities compound.
• This included one large willow tree that was pollarded by the in-house arb team using sectional felling and rigging techniques.

Installation of Wildlife Habitat Features:

• Hibernacula: Three hibernacula were installed, using a mix of site won materials such as stone and logs to provide a variety of overwintering options for amphibians, reptiles, and invertebrates.

• Bat Boxes: Boxes suitable for species such as Noctule, Daubentons, Pipistrelle and Bechsteins bats were placed on suitable trees, particularly near the rides and glades, where there is increased foraging opportunity.
• Bird Boxes: A variety of bird boxes were installed, targeting different species such as Thrush, Tits and Firecrest. These were positioned at different heights and locations, offering nesting opportunities in both open and sheltered spots.
• Dormouse Boxes: Dormouse boxes were placed approximately 1.5m from the ground in locations near to potential food sources with the entrance hole facing in towards the tree trunk to reduce occupation by birds.
• Barn Owl Box: An Ash tree located in a suitable position for a barn owl box was found on site. The in-house arb team undertook aerial crown removal, turning the tree into a monolith (a tree reduced to its main stem) upon which the barn owl box was fixed.
• Dead Hedge: The Keystone Habitats team created approximately 450 linear meters of 1-metre-tall dead hedge along the edges of the rides and glades.

Outcomes

Enhanced Biodiversity in Line with BNG Recommendations:

• The creation of rides and glades have significantly improved light penetration to the forest floor which should stimulate a more diverse range of ground flora. In addition, the improved foraging conditions should support a wider array of invertebrates and small mammals.
• The coppicing and pollarding of trees has created a more varied woodland structure, providing different canopy levels and promoting the growth of bushy understory vegetation.
• The creation of 450 linear meters of 1-meter-tall dead hedge was a significant additional habitat feature, over and above the BNG enhancement recommendations. This will provide commuting and refuge opportunities for a range of species, in particular dormouse and other small mammals.
• Installing the dead hedge was the most efficient use of the felled woody material that would otherwise have had to be chipped and removed from site.
• The creation of three hibernacula has provided critical overwintering habitats for herpetofauna and invertebrates.
• The installation of a total of 23 bat and bird boxes as well as a single barn owl box has provided roosting and nesting locations that were otherwise lacking in the young plantations.
• The installation of 12 dormouse boxes should help increase dormouse population density in the area.

No Impact to underground Services:

• The careful planning and precise execution of works ensured that no disruption occurred to the underground services. Mapping, consultations with the client, the installation of ground protection crossing points and buffer zones around the services allowed for safe operations.

Conclusion

• The careful planning and implementation to avoid underground services meant no damage to services occurred and no health and safety protocols were breached.
• The Keystone Habitats team implemented all the BNG enhancements recommended by the Keystone Ecology team and instructed by the client.
• The successful use of habitat creation techniques such as coppicing and pollarding, the installation of wildlife boxes, dead hedges and hibernacula will no doubt provide ecological benefit. Follow up BNG assessments in the years to come will provide data that will feed into further enhancement recommendations if necessary.
• Most importantly the client was very happy with the professional manner in which all the works were undertaken and how the site was left at the end of the job.