Department of Heritage approves deer fencing and Rhododendron clearance to save protected Wicklow woodlands

By Hugh O'Farrell Walsh, The Wicklow People

Two major conservation interventions have been approved for Glendalough and Derrybawn, with the Department of Heritage determining that both deer-proof fencing and largescale Rhododendron removal are now necessary to halt the decline of the most vulnerable native woodlands in the Wicklow Mountains special area of conservation (SAC).

The decisions set out the scientific and legal basis for the works needed and confirm that each project is directly connected with the management of the area, which is protected by EU laws.

The first determination concerns the installation of 300 metres of deer-proof fencing in bracken ground beside old sessile oak woods.

The Ecological Assessment Unit (EAU) found that decades of heavy browsing by invasive sika deer and feral goats have prevented natural regeneration of native oak, stripped ground flora and left the habitat in “bad” conservation condition.

The documents note that “heavy browsing eliminates sessile oak seedlings, native saplings and ground flora before they can mature”, a pattern that has pushed the woodland towards long-term structural collapse.

The fencing, built to 1.8 metres is intended to create exclosures where oak seedlings can grow without being eaten.

The works form part of the Glendalough and Derrybawn Woodland Project and were previously identified in the 2010 management plan and its 2023 review.

The EAU concluded that the fencing is a necessary conservation measure under Article 6 of the Habitats Directive. Once installed, the fenced areas will be lightly planted, scarified and managed for bracken control over five years to support sapling establishment.

The second determination deals with invasive Rhododendron ponticum, which has spread widely through the oak woods and adjacent slopes. The documents warn that once Rhododendron dominates an area, “few native plants survive”.

Both projects were assessed for potential impacts on the Wicklow Mountains special protection area (SPA), designated for merlin and peregrine falcons.

The EAU found no significant adverse effects, noting that the works are temporary and localised, and that restoring native woodland structure may indirectly benefit raptor prey species.

For the fencing, the determination recommends high visibility markers and careful placement to avoid low flight corridors, but concludes that the barrier poses negligible risk to the SPA’s raptors.

In each case, the EAU determined that the works are “entirely comprised of activities that directly support the conservation objectives” of the SAC.

With oak regeneration stalled and invasive shrubs advancing, the department’s ecologists argue that active intervention is now essential to prevent further deterioration.