From 30,000 acorns to mighty oaks — with luck and a little help
NPWS outdoor staff, James Doherty, left, PJ Murphy, centre, with NPWS Conservation Ranger, Tim Cahalane, plant oak saplings in Derrycunnihy woodland. Picture: Valerie O'Sullivan/
A new project in Killarney National Park has seen park staff collect and then germinate thousands of acorns to help nature along.
Killarney has about 3,000 acres of oak, most of it sessile oak. It is largest native woodland remaining in Ireland and a throwback to when the island itself was covered. Oak was cut down extensively during the colonial era in Killarney and its surrounds. To this day clumps of stitchwort, a white-flowered plant, will be found where old oaks once grew. Most of what is remaining is found around Lough Leane, with place names such as Derrycunihy (Daire means oak) a clear indication of the type of woodland involved.
But while the oak area in Killarney is extensive, and plenty of acorns are produced in mast years years such as 2022, there is precious little regeneration. Very little grows on the forest floor even in the most western end such as Tomies Mountain, where a new walking trail has opened.
The numbers of Red Ireland’s oldest mammal have soared since they were at extinction levels in the 1970s. Sika, the Japanese species introduced in the 19th century, is even more efficient at denuding the woodland floors. Sheep ‘straying’ from nearby hill commonage are another major threat to saplings. All of these ensure oak reproduction is minimal in Killarney.
And alongside the large predators are long-tailed field mice, rabbits, squirrels, and voles who feed on nutrient-rich acorns. Even the wood pigeon likes an acorn or two.
There is another phenomenon too — Killarney itself. With its moist mild climate, the mossy woods provide an ideal carpet for a falling acorn. This bedding ensures quick and steady gemination and tap roots quickly taking hold. But there it stops...
As far back as the 1930s ‘the paucity and patchiness of successful generation’ in Killarney, puzzled ecologists and foresters as noted in a 25-year monitoring of regeneration in an exclosure in Tomies wood, by Daniel Kelly published in 2002.
This was the first of its kind over such a long period and he concluded that successful oak regeneration in western Ireland is to be expected only in unshaded or lightly-shaded sites where grazing levels are low.
As part of the drive to gather the acorns and plant them in protected areas, enclosures were established 20 years ago, where high fencing keeps out predators — these now show remarkable growth. Further fencing is underway with helicopters bringing stakes to difficult terrain.
The devastating fire in April 2021 which threatened the oak woods is providing a further impetus in Killarney — more than 30,000 acorns were gathered in 2022. Supervised by the Park’s horticulturalist, Gerry Murphy, and gardener, Stephen Moore, the acorn project "has seen high levels of germination in early spring".
A project spokesman said: "Areas with suitable light gaps in the woodland canopy were identified in the Derrycunnihy and Muckross woodlands. Planting of some seedlings originally collected as acorns and seed in each area is underway to supplement natural woodland regeneration. These seedlings are protected by tube shelters which can also prevent grazing by small mammals and provide some protection against competition from other plants."
In tandem with this, the maintenance of deer A-frame exclosures in the Ullanes area of the National Park is ongoing to maintain conditions where woodland regeneration can occur. These were originally constructed in the early 2000s for the purposes of woodland restoration and grazing control.
Following the 2021 fire which resulted in damage to the Cuckoo Woods area of the National Park, plans are currently being drafted to repair this and improve the connectivity of this woodland too to other more remote woodlands for bat species.
Ecologist Pádraic Fogarty, author of the groundbreaking which for the first time examined how national parks here are managed, welcomes such projects particularly in Killarney which was Ireland’s first national park. But he warns that tackling the overgrazing is key: "The Park is under intense pressure from overgrazing, by deer in particular, and that has to be addressed."
No one knows the true numbers of deer, for instance, because there is no census. One way forward is to translocate the deer to the land being bought by the NPWS on the perimeter of the original park.
He notes: "Reducing grazing pressure is needed to restore the ecosystem, not just for the growth of new trees, and tree-planting is not a substitute. It also comes back to the fact that we still don't have a plan for Killarney National Park that would address the various issues. This was promised by minister Malcolm Noonan but where is it?"
