Coillte Reaches Major Biodiversity Milestone – 30% of Estate Now Managed Primarily for Nature
- Strategic goal delivered ahead of schedule, highlighting Coillte’s commitment to the protection and enhancement of Ireland’s biodiversity
- 134,000 hectares across Ireland now prioritised for nature management
- Coillte publishes new ‘Forests for Nature’ booklet detailing its biodiversity strategy and nature restoration works
Thursday, 4th September 2025: Coillte today announced the early delivery of a significant environmental milestone, having increased the proportion of its estate managed primarily for nature from 20% to 30%, four months ahead of schedule. This achievement represents the successful fulfilment of a key strategic objective outlined in Coillte’s strategic vision for its forests, first published in 2022. As a result, 134,000 hectares of land – an increase of 44,000 hectares – have been identified to be managed primarily for biodiversity across Ireland.
This progress has been made possible through Coillte’s BioClass system, a science-based framework developed to identify and classify the ecological value of areas on the Coillte estate. The BioClass system, functions as a habitat scoring process, assessing forests, bogs, and open landscapes based on defined ecological criteria. Using this system, Coillte’s team of ecologists and foresters systematically ranked sites according to their natural value, enabling the organisation to identify key biodiversity areas and implement bespoke management plans to protect and enhance them. Having reached this important target, Coillte reaffirmed its long-term commitment to managing greater areas of its estate primarily for nature.
“Forests for Nature is one of the four strategic pillars in Coillte’s long-term vision for the forest estate, and we’re proud to have reached this key milestone – expanding the area of land managed primarily for nature and biodiversity from 20% to 30%, ahead of schedule,” said Mark Carlin, MD of Coillte Forest. The importance of protecting and enhancing biodiversity is increasingly recognised, both in Ireland and globally. Coillte’s estate represents one of the country’s most significant biodiversity resources, encompassing a rich tapestry of habitats including coniferous, mixed and broadleaved forests, as well as open bogs, heathlands, lakes and rivers.”
“Looking ahead we remain committed to our long-term ambition of managing greater areas of our estate primarily for nature, while also ensuring the productive areas of the estate are carefully managed for the long-term supply of sustainably grown, certified Irish wood, supporting the delivery of sustainable homes and rural jobs. This goal is part of our broader mission to balance the multiple benefits that forests provide – for climate, nature, wood and people.”
To mark its commitment to enhancing biodiversity, Coillte has produced a ‘Forests for Nature’ booklet which outlines Coillte’s approach to biodiversity management. It also showcases six nature restoration case studies demonstrating Coillte’s approach to managing forests and other habitats. Included are two examples of forest biodiversity projects at Glenart, Co. Wicklow and Hazelwood Forest Restoration Co. Sligo; the Uplands Project at Dublin Mountains Makeover; a Peatlands Case Study at Aghrane Bog, Co. Galway; a Water Case Study at Devil’s Glen, Glanmore, Co. Wicklow; and a Rare Species Case Study on the Lesser Horseshoe Bat at Rossacroo, Co. Kerry.
Coillte’s strategic vision for its forests is designed to optimise its contribution to Ireland’s climate targets and includes a range of actions aiming to capture approximately 28 million tonnes of CO2 from the environment by 2050. It aims to bring more focus to climate action, setting ambitious new targets on biodiversity and recreation, while continuing to deliver for the forest and wood products industry.
Coillte is responsible for the management of 440,000 hectares of primarily forested land, which represents 7% of the country. Since its establishment in 1989, it has enabled the development of a vibrant forestry and wood products sector that supports rural employment throughout Ireland. While sustainability has always been central to the way in which Coillte manages the forest estate, Coillte believes that the growing climate and biodiversity crises, as well as societal demands for housing, jobs and wellbeing, are driving a need for greater change.
Further information:
Coillte Forests for Nature Case Studies
1.1 Forest Case Study 1: Glenart, Co. Wicklow
Coillte’s Glenart biodiversity area is a beautiful mixed forest located near Arklow in south Co. Wicklow. It was selected for biodiversity enhancement because it is located on a possible ancient forest site. Ancient forest sites in Ireland are rare and therefore are of particular nature conservation value. There is evidence of forest cover in Glenart since the 1600s. Sites with a long history of forest cover tend to support higher levels of biodiversity, including rare species and woodland specialists (species that only occur in woodlands), as compared with woodlands of more recent origin. Their soils can also be important reservoirs of carbon.
The forest in Glenart is largely dominated by mature oak and Norway spruce with some Scots pine, ash, birch, European larch, beech and grey willow. There is an understory of holly and hazel in parts. The ground flora is typical of native oak forests on acidic bedrock, and includes great wood-rush, bilberry and ling heather.
The main issue in Glenart is that the forest is relatively even-aged i.e. most of the trees in the canopy are approximately the same age. The forest doesn’t have the multi-layered structure that is found in natural forests. While there are lots of mature trees in Glenart, there are few saplings and young trees to renew the canopy when gaps form as trees die or are blown over. There are also few big, old, veteran trees, which are rare, but important because they can support a multitude of species (small mammals, birds, insects, fungi) above and below ground, and are very important for the ecological functioning of forests. Deadwood is also not abundant in Glenart. Deadwood is a hugely important part of the forest ecosystem because it is part of the nutrient recycling system, and deadwood in various forms of decay can support a myriad of insects, fungi and bacteria.
A close to nature approach is being adopted in the management of the forest in the Glenart biodiversity area. The aim is to gradually transform the forest over time to a multi-aged and layered diverse forest that is regenerating naturally, has plenty of veteran trees and abundant deadwood.
The silvicultural system adopted is called Continuous Cover Forestry (CCF). Individual trees are removed periodically to create gaps and to allow light to reach the forest floor, while retaining a permanent forest floor. Gaps created by periodically thinning out trees provides the conditions required for tree seedlings to emerge. Some trees are identified as future veterans and are protected. Standing and fallen deadwood is created to provide new microhabitats to support biodiversity.
The first CCF thinning took place in Glenart in 2023 and the next is likely to happen in 2030.
The benefit of a CCF approach to managing sites such as Glenart is that the forest ecosystem is protected and enhanced. The ecological value of the forest will increase over time as it is restructured to a multi-layered forest with a wide range of microhabitats to support a range of species. The forest will be able to regenerate naturally as light gaps are created thus reducing the interventions required.
1.2 Forest Case Study 2: Hazelwood Forest Restoration Co. Sligo.
Hazelwood forest is situated on the western shores of Lough Gill and the Garavogue River, close to Sligo town. It dates back to at least the 1650s and sites with a long history of forest cover tend to support higher levels of biodiversity, including rare species and woodland specialists, and so this fact adds significantly to the uniqueness of Hazelwood.
There are two different types of forest habitat present in Hazelwood: 1) alluvial forest in the northern half of the forest and 2) mixed broadleaf/conifer forest to the south.
Alluvial forests are situated on floodplains of rivers, and they have a unique ecology because they flood regularly when river water levels rise. Hazelwood, is in a highly natural state, making it one of the most significant remaining alluvial forests in Ireland, if not in Europe. As a result, Hazelwood is mapped as a Coillte biodiversity area, prioritised for biodiversity enhancement. It is also included in the Lough Gill Special Area of Conservation (SAC).
The alluvial forest at Hazelwood is dominated by willow, alder, ash, birch, aspen, spindle and oak. The ground flora is species-rich and includes meadowsweet, marsh marigold, flag iris and sedges.
From an ecological perspective, the main issue at Hazelwood was that large portions of the forest were covered with dense stands of invasive shrubs – rhododendron and cherry laurel. Dense growth of these shrubs completely suppresses the native forest vegetation.
Between 2005-2009 Coillte restored 25ha of the alluvial forest as part of a major restoration project funded by the EU LIFE Nature fund. The rhododendron was removed from the wettest part of the alluvial forest, and the native forest vegetation has since regenerated very well. Since 2009, Coillte has removed a further 43ha of invasive species (cherry laurel and rhododendron) from this high-quality forest habitat, enabling regeneration. A wonderful array of native flowers are reappearing, particularly marsh marigold, wood anemone and bluebells; along with young tree seedlings of willow, aspen, and birch which are emerging in the wetter areas, while on drier soils species such as oak, holly and hazel are present.
In the southern part of Hazelwood, the main ecological issue to be addressed was that the mixed forest is relatively even-aged, which means that most of the trees in the canopy are approximately the same age. The management objective here is to enhance the biodiversity value of the forest by using Continuous Cover Forestry principles.
In 2025, Coillte was proud to receive the RDS Forestry Award for Native Woodland Conservation for the ecological restoration works at Hazelwood. As a result of the forest restoration works, the condition of the alluvial forest habitat will improve over time. Regeneration of native flora, trees and shrubs is starting to occur, and the species and structural diversity of the wider forest is being improved. This will ensure that the forest will thrive and sustain itself in the future for everyone to enjoy.
- Uplands Case Study: Dublin Mountains Makeover
The Dublin Mountain forests are among Coillte’s most popular forest recreational sites and provide a growing urban population with a wonderful place to experience nature. To accommodate the increasing amenity use of these forests, Coillte took the decision to transform its management approach in these uplands, from one of primarily wood production, to one of recreation and nature conservation in a way that will also benefit the forest and open habitats present.
The objective of the Dublin Mountains Makeover project is to gradually transform 700ha of nine Coillte forests to improve habitats for wildlife, enrich the forest’s recreational appeal for people, improve the wider landscape’s aesthetic value and make it more resilient to climate change.
The management approach is to manage these forests under Continuous Cover Forestry (CCF) principles, which maintains a permanent forest canopy and gradually transforms the forests into multi-generational, more diverse forests in terms of species, age and structure. To implement CCF, the forests are carefully thinned, which means that individual trees are selected and removed to create gaps and to allow light to reach the forest floor, while retaining permanent forest cover. Over time, this will improve the structure and diversity of these forests, which in turn will increase their habitat value for plants and animals.
At some locations, the forest is being converted to native forest, by removing the conifer trees and replanting with native species such as Scots pine, birch, rowan, oak, holly and willow. These species will also appear in the CCF managed forests over time.
Since the commencement of the project in 2020, CCF management has been initiated on 190ha of the Dublin Mountains forests. A further 60ha have been replanted with a mix of native trees and shrubs.
At higher altitudes, the Coillte properties include almost 200ha of open habitats: wet heath, dry heath and small areas of blanket bog. These habitats are also being protected and enhanced.
The delivery of the project is further enhanced through close collaboration with the Dublin Mountains Partnership (DMP)* thereby working together to protect the resource and enhance the recreation experience and partner with the key stakeholders in the area. The Dublin Mountains Makeover project will continue for many decades, delivered in a way that minimises disruption to local residents and visitors, while locking in the benefits for nature, recreation and the landscape that will be enjoyed by generations to come.
*The DMP aims to provide and manage sustainable recreation in the Dublin Mountains. Partners include Coillte, NPWS, Dún Laoghaire Rathdown County Council, South Dublin County Council, Dublin City Council and the Dublin Mountains Initiative (DMI), an umbrella group representing the interests of recreation users of the Dublin Mountains.
- Peatlands Case Study: Aghrane Bog Co. Galway
Aghrane (also known as Aughrim Bog) is a raised bog in north-east Galway. This biodiversity area was selected for bog restoration because it is designated as a Special Area of Conservation (SAC). The site is therefore of international nature conservation significance.
Raised bogs are dome-shaped peatlands that occupy former lakes in the landscape. Most started to form at the end of the last ice age about 10,000 years ago and many contain deep deposits of peat of up to 12m.
The main source of water and nutrients in raised bogs is from rainfall. As a result, the peat is very nutrient poor, as well as being waterlogged. The vegetation is dominated by Sphagnum mosses (which acidify their environment), sedges and heathers, all of which are adapted to the wet and acidic conditions.
Raised bogs tend to contain a mosaic of peatland microhabitats including heathery hummocks, hollows with lawns of Sphagnum moss and bog cotton, and bog pools.
Aghrane (Aughrim) bog is one of the largest raised bogs in Co. Galway. It was originally restored in the mid-2000s as part of a Coillte EU LIFE Nature project when productive conifer trees were removed, invasive species were controlled, and drains were blocked.
In the period between 2022-2025,enhanced restoration measures have been implemented, in collaboration with NPWS, in order to build on the restoration works completed to date and to apply new restoration techniques.
These measures aim to raise the water table further to support the development of raised bog habitats and to promote active bog growth.
Drains were blocked in the bog with a mixture of peat and plastic dams, in order to pool the water and maintain a high-water table on the bog.
NPWS have been monitoring the area of ‘active bog’ on the site, which means areas of bog that support peat-forming vegetation such as bog mosses and sedges, and this area has expanded by 20% since 2018, which is a very positive result for biodiversity and for carbon capture in this important habitat for nature.
- Water Case Study: Devil’s Glen, Glanmore, Co. Wicklow
Coillte’s Devil’s Glen forest is a beautiful mixed forest occupying a steep river valley near Ashford, Co. Wicklow. Approximately 135ha of the forest at Devil’s Glen was selected by Coillte as a biodiversity area because it is a large old woodland site with a long history of forest cover that has retained features of natural forests. There is evidence that broadleaved forest cover has been present at Devil’s Glen since the 1600s and therefore it is considered Ancient Forest site and consequently has a high biodiversity value.
There are special features at Devil’s Glen that add to its ecological value. The forest is bisected by a rocky gorge up to 100m deep, through which the Vartry river flows. It supports a range of salmonid fish species, especially sea trout (Salmo trutta trutta) and a small population of Atlantic salmon (Salmo salar), as well as river lamprey (Lampetra fluviatilis).
The predominant forest type at Devil’s Glen is mixed forest including conifer trees such as Douglas fir and Scots pine, and broadleaf trees including sessile oak, beech, sycamore, sweet chestnut, birch and rowan. There is an understorey of holly and hazel in parts. Along the Vartry River is approximately 14ha of native forest, where the forest canopy is dominated by sessile oak, birch and rowan (or mountain ash).
Throughout the forest, a good ground flora of typical woodland forest plants can be seen. Woody shrubs such as bilberry (or frachan) and ling heather are plentiful, also ferns (including hard fern, polypody and broad buckler fern) and flowering plants such as great wood-rush, sorrel and a carpet of mosses. In spring, the bluebell, wild garlic and wood anemone produce a colourful display. A particularly unusual plant present at Devil’s Glen is the toothwort (Lathraea squamaria), a parasitic plant that taps into the roots of trees for its nourishment. It is a forest specialist species and tends to occur in forests that have a long history of forest cover.
From an ecologicial perspective, the main issue at Devil’s Glen was the dense growth of the invasive species cherry laurel and rhododendron in the forest, which extended to an area of about 11ha, mostly around the car park and along the Vartry River. One of the main management objectives was to remove both of these invasive species because these shrubs form dense and dark growth that completely suppresses the forest flora and prevents natural regeneration of trees and shrubs. In 2023/24, most of the dense cherry laurel was treated (8ha) and the remainder is due to be addressed in the near future. In the coming years, the natural vegetation will start to reappear, and a good forest flora will become more visible.
In partnership with Inland Fisheries Ireland, Coillte introduced a further objective, which is to create additional spawning areas for salmonids in the Vartry River, which are restricted due to the dam located upstream at the Roundwood reservoir. These works commenced in 2024 on a 1.5 km stretch of the river, and five new sea trout spawning areas (redds) resulted during the spawning season. The operations comprised of placing felled trees in the river, which creates leaky dams that restrict water flow, and placing gravel upstream of the secured trees to provide new spawning bed habitats.
- Rare Species Case Study: Lesser Horseshoe Bat at Rossacroo, Co. Kerry
The lesser horseshoe bat (Rhinolophus hipposideros) is Ireland’s rarest bat species. It is primarily found in the western parts of the country, in counties Cork, Kerry, Limerick, Clare, Galway, and Mayo. The reason for this may be that these counties experience a milder climate with rare frosts, which seems to favour the bats. They favour habitats with trees: forests, scrub, hedgerows and treelines. They roost in old buildings or caves surrounded by trees or hedgerows.
Coillte has a very positive contribution to make in the long-term conservation of this species, being the custodians of numerous lesser horseshoe bat roosts, including several Special Area of Conservation (SAC) designated roosts, and large tracts of supporting forest habitat surrounding roosts.
Rossacroo is one of many Coillte properties that support internationally important SAC populations of lesser horseshoe bat. An old, derelict cottage located within Rossaacroo forest is used by the bats as a maternity roost in the summer months, but some repairs were needed to maintain the roost in a suitable condition.
In winter 2022/23, the roost enhancement works were completed, including replacing the existing corrugated roof with a natural slate roof, removing the chimney, reinforcing the walls and managing vegetation. The objective of these improvements, which were jointly funded by Coillte and NPWS, was to create ideal roosting conditions for the species and to boost bat numbers.
Subsequent monitoring by NPWS recorded an increase in the numbers of bats roosting in the building, from just 37 bats in 2022 to over 100 bats in 2024 and more than 150 bats in 2025, moving this site to “favourable conservation status”, a significant achievement, a significant achievement for the protection of this bat species in Ireland.
Together with NPWS, we are actively exploring possibilities for roost enhancements at other Coillte properties, such as Dromore, Co. Kerry and Brackloon Wood, Co. Mayo. And we are partners in a major project called the Moorehall Masterplan, which is led by Mayo County Council, in partnership with NPWS. The aim of the Masterplan is to protect the natural built and cultural heritage through the development of a nature reserve which will, amongst many things, maintain a world class habitat for the lesser horseshoe bat.
Maintenance and enhancement of roosts is a significant component of the national Species Action Plan (SAP) for lesser horseshoe bat, which was developed by NPWS in 2022. Implementation of the SAP for lesser horseshoe bat requires co-operation across a broad range of stakeholder organisations, such as DAFM’s Forestry & Agriculture Divisions, the Heritage Council, Vincent Wildlife Trust, Bat Conservation Ireland, Transport Infrastructure Ireland and Local Authorities. Coillte participates in implementing the SAP through a Steering Group hosted by NPWS.
Coillte’s contributions, through roost maintenance works and careful forest management are vital to the long-term conservation of the species.
