Ireland’s reputation for being largely treeless, with stubbornly low planting rates and a history of monoculture forestry – non-native trees often planted in the wrong places – may be changing.
But it is not simply about planting native trees at scale in the right place. It’s about successfully implementing a multilayered approach, including forests that ensure sustainable timber supplies, capturing carbon at scale, and enhancing wellbeing – also known as ecosystem services, where nature delivers benefits to humans.
Forestry for nature/biodiversity is part of this and is where transformation is gathering pace. The extent to which State-owned commercial forestry operator Coillte is factoring in this approach, where appropriate, is notable. Some 30 per cent of its vast estate (134,000 hectares) is now managed primarily for nature; a target achieved this year ahead of schedule.
It is remarkable how practices of the past, while damaging – such as allowing the dominance of Sitka spruce – have not totally undermined forestry heritage. The ability of nature to rebound is extraordinary.
RM Block
That is evident when venturing into Co Wicklow’s forests. It is where there are many pockets of “ancient forests” dating back to the 17th century and of the areas forested since the 1830s, which featured on the earliest ordnance survey maps.
Those with a long history of forest cover are often more species-rich than those of recent origin, “and thus are potentially of higher conservation value”, says Coillte managing director Mark Carlin.
“Forests for nature is one of the four strategic pillars in Coillte’s long-term vision and we’re proud to have reached this key milestone,” he adds, “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.”
Prioritising nature requires hard decisions in determining which are of conservation value and worth enhancement – and, critically, what criteria do you apply in such circumstances, knowing even in the most biodiverse sites, there are particular challenges.
Then there is the problem of forests being even-aged with uniform characteristics, including some broadleaved and native forests. “A close to nature approach to forest management provides an opportunity to improve forest structure – through selectively thinning the forest, which in turn has the benefits for nature and wildlife by diversifying the habitat,” Carlin explains.
Known as continuous cover forestry (CCF), this approach enables the transition to happen gradually to more biodiverse forests with trees of different sizes.
BioClass was developed by Coillte as a science-based procedure for assessing the ecological value of sites. In assessing forests, bogs, and open landscapes based on defined ecological criteria, those that most closely resemble natural habitats have the highest value. It is about defining “naturalness”, and typically there is a multilayered forest structure, long history of forest cover and abundance of native trees, says ecologist and environment technical lead at Coillte, Aileen O’Sullivan.
Stepping into Glenart forest in Co Wicklow, such qualities are immediately evident; a mixed forest dominated by mature oak, Norway spruce (planted in the ’60s), ash, birch, beech and willow with clear indication of its ancient lineage. “There is an understory of holly and hazel ... you can see there’s a very vigorous and thriving flora of native plants, typical of acid soils,” she adds.
The dominant plants are woodrush, heather and bilberry, but also hard fern, slender St John’s-wort and champsia efleciosa, known as “wavy hair grass”.
Having “all native trees” is not the main priority; “it’s really about the structural diversity, the ground vegetation, and over time, getting bigger trees, a mix of bigger trees and small trees. And the way to make that happen is through continuous cover forestry,” O’Sullivan adds.
The animals are typical of all sorts of forests and include pine marten and red squirrel. Managing this through CCF is not necessarily going to bring in more birds and mammals but will probably enhance invertebrates and soil fauna, she says.
Woodpeckers, red kites, long-eared owls, songbirds and tits are typical inhabitants, O’Sullivan says. As she speaks, the screech of a bird of prey rings out, probably a buzzard or sparrowhawk.
Carlin outlines how CCF benefits Glenart. A more traditional forest is planted primarily for wood, thinned probably every four or five years until the clear-fell stage. Then trees are taken out and replanted, a good cycle for wood production.
“It’s a very good cycle also for climate, because what you’re doing is you’re sequestering carbon dioxide into trees and you’re taking the wood out, storing that in wood products and then replanting,” Carlin says.
With CCF, keeping a permanent canopy is pursued, taking out the smallest trees to get the bigger and better quality trees. “You actually take out some of the larger trees to open up space, so it’s all about light through the canopy, and if you open up too much light, then you get too much vegetation like briars and then nothing can grow underneath.”
Dead trees are also left on the ground to further improve floor biodiversity.
It’s a delicate balance of opening up enough light so it gets through to the floor to encourage natural regeneration. This is where the problem of deer browsing can arise, as they feed on leaves, soft shoots or fruits of high-growing, generally woody plants such as shrubs.
One of the most important actions for biodiversity is getting deer under control, he says. Fencing is expensive, while keeping them under control means less planting to do. “That’s probably one of the biggest challenges we have on CCF.”
Moving to the mixed forest in Devil’s Glen near Ashford – a steep river valley bisected by the Vartry river – reveals different distinguishing characteristics, particularly around water management and supporting a range of salmonid fish, including Atlantic salmon, sea trout and river lamprey with the help of the natural cover of trees.
From the ecological perspective, dense growth of invasive species (cherry laurel and rhododendron) is the main threat, which can completely suppress forest flora and prevent natural regeneration of trees and shrubs. Most of the menacing laurel has been blitzed, Carlin says, in the hope that natural vegetation will reappear and good forest flora will reassert themselves.
Introduced to Ireland as cover in old estates to facilitate shooting and hunting, the species is notorious in that nothing grows underneath. It resulted in an ecological “dead zone” in a beautiful area that is Coillte’s most visited forest. Deploying new technological solutions in the form of stem injections, however, has achieved a good kill rate.
Availing of cover from sessile oak, birch and rowan, Coillte is working with Inland Fisheries Ireland and the National Parks & Wildlife Service to create additional spawning beds for salmonids by placing felled trees in the river, which creates leaky dams that restrict water flow and deeper pools, and putting gravel upstream of secured trees.
Getting the shading right and removing barriers to the movement of fish is bringing a significant dividend, O’Sullivan says, as well as cooling water temperature, which is being elevated by climate change.
Coillte is showcasing these forests to illustrate its approach to managing woodlands and other habitats along with Hazelwood Forest restoration in Co Sligo; an uplands project known as “Dublin Mountains Makeover” (maximising recreation for an urban population, while transforming 700 hectares of habitats), a peatland initiative at Aghrane Bog, Co Galway and a rare species study involving the lesser horseshoe bat at Rossacroo, Co Kerry.
Carlin brings it all back to achieving a better balance in pursuing forests for wood, climate, nature and people: “Coillte believes the growing climate and biodiversity crises, as well as societal demands for housing, jobs and wellbeing, are driving a need for greater change.”
Forests, in the way they are managed, are not only arresting biodiversity decline, but their “nature” and surroundings are also building resilience in countering climate change impacts such as stormier weather and floods.
The era of being a treeless country with little forest culture is changing, O’Sullivan says. This has been enabled by the restoration of forests across a wide variety of landscapes by “trying not to go against nature”.
