Killarney and the Woodland Heritage


I am lying on the ground, my eyes closed. The dampness of the soft moss blanket I am resting on is slowly creeping through my clothes. I smell wet earth and fresh foliage. A soft breeze creates rustling sounds in the canopy above. It is late spring in the woodlands of Killarney National Park. The trees have almost fully unfolded their new leaves and the wildflowers on the forest floor are soaking up the little sunlight that is still filtering through the green baldachin. Primroses and wood anemones have already done their job for this year and only a few latecomers still showcase their delicate flowers. Wild garlic and bluebells however are in their prime, blanketing the field layer of the forest in white and blue. At this early hour the sun is still hidden behind the peaks of Mangerton and Torc Mountain and the dawn chorus is just starting. The voices and songs of blackbird, robin, wren and other birds are slowly building. Single performances turn into duets, others join in and soon there is an ensemble of harmonies echoing through the forest. This is the sound of spring.

A few months later the sounds of the forest are quite different. It is now October in Killarney and yet again I am sitting in the forest in semi darkness. Suddenly the silence is disrupted by a deep bellowing. It’s a sound that seems to come right out of the bones of the earth and in the calm before dawn it echoes eerily from the mountainsides. The call is answered closer to me by an ear shattering roar and I belief to see a dark shadow moving through the trees ahead. The red deer rut has something primeval, it is an event that has been performed in the forests and around the lakes of Killarney every autumn for thousands of years. Every year the deer come down from the mountains into the lowlands. Here the stags round up the does and fight for the right to mate. The bellowing and roaring is often followed by violent head tossing and sometimes the crashing of antlers.

A few weeks later the deer retreat from the valleys and silence returns to the woodlands. It’s the calm of the approaching winter. The dark green tones of summer have been replaced by warm shades of brown and yellow. The spectacle of autumn however is short lived in these parts. The first storms can come early and strip the trees bare before they had a chance to change into their full autumn gown. Robbed of their foliage the masters of the forest appear in their most stark, almost menacing, fashion. The bare branches of an old oak tree reaching for the grey winter sky is, for me at least, one of the most awe inspiring sights in nature.


For the longest time trees have been admired and even worshipped and their sheer size and longevity makes us look at them in wonderment. We are also aware that trees produce much needed oxygen and provide us with food, building material and fuel. Yet trees are still widely seen as inanimate objects without a conscience and emotions. Only in recent years has scientific evidence confirmed that trees as well as other members of the plant kingdom are more than they appear to be. We know now that trees form communities and communicate with each other through chemical messaging both underground through their root system as well as above ground through the air. Trees also support their offspring if it is growing nearby and not only actively react to changes and threats in their environment but also warn their companions.

Ireland unfortunately has a rather bleak history when it comes to trees and in the early 19th century forests had almost completely disappeared from the green island. Back then only 1% of the country was covered in trees and only a small part of this percentage consisted of old growth woodland. The ancient forests that had once covered some 80% of Ireland’s landmass were all but gone.

How it came to this almost complete deforestation is hard to understand especially if the importance that trees had played in early Irish heritage is taken into account. Sacred trees were often the spiritual centre for communities, they were the place to hold rituals, to pass judgement or to crown a new chieftain or king. From the earliest time trees were treated as sacred objects and they were believed to have a deep connection to the spiritual world which is reflected in numerous legends and folk tales. These tales always follow the same line: An ignorant person interferes with a sacred tree, in Ireland often referred to as fairy tree or fairy bush, either by removing parts of the plant or chopping down the whole entity. What follows for the unfortunate person are various degrees of misfortune or even death. The believe in the connection of trees to the Otherworld, the realm of spirits, fairies and other magical beings, lives on into the present and fairy trees and fairy bushes are still very much respected. Not too long ago a section of a planned motorway had to be redesigned to circumnavigate a fairy bush, an old hawthorn, that has a firm place in local folklore. The pagan origins of these sacred trees also found their way into the Christian religion and so-called rag trees which are often located near a holy well are common all over Ireland.

The oldest written insight into Ireland’s connection with trees is shown in the Ogham alphabet. Ogham was the first written language in Ireland and is often referred to as the tree alphabet. It consisted of 20 letters, each made of a combination of short vertical, horizontal and tilted lines. These letters were known as feda (trees) or nin (branch or fork) and according to some medieval texts each letter was associated with a specific tree. Today this theory is being contested for various reasons. The most convincing argument is that it would have been pretty much impossible naming all 20 letters after trees considering the limited number of species present in Ireland and the fact that the Irish names of some of those trees start with the same letter, e.g. hazel (coll), holly (cuilend) and rowan (caerthainn) all start with a C. It is however still widely accepted that at least eight of the Ogham letters were representing a tree species. The B (breith) for example stood for the birch, the F (fern) for the alder and the D (dair) for the oak. It is now thought that the remaining letters were named with poetic alternatives that described characteristics of certain tress. The L (luis) might have stood for flame to represent the fiery red rowan berries and the T (tinne, meaning bar of metal or iron) might have stood for the dense, hard wood of holly. Ogham was in use from around the 4th to 8th century but it is possible that it dates back much further.

Dating from the same time period are the Brehon Laws. This law system which was named after wandering lawyers, the brehons, is recognized as the oldest in Europe and remained in place almost unchanged for centuries. Under these laws trees and shrubs were granted special protection according to their importance to the community and the penalties for breaking these laws were severe. The trees were divided into four classes, roughly mirroring classes in early Irish society. These were the airig fedo, the nobles of the wood (oak, hazel, holly, yew, ash, scots pine and crab apple), the aithig fedo, the commoners of the wood (blackthorn, elder, spindle, whitebeam, arbutus, aspen, juniper), the fodla fedo, the lower divisions of the wood (alder, willow, hawthorn, rowan, birch, elm, cherry) and the losa fedo, the bushes of the wood (bracken, myrtle, furze, bramble, heather, broom, wild rose).

Despite their spiritual and practical importance trees seemed to have already been in decline at the time. Ancient law texts and other sources describe Ireland as a landscape of fields interspersed with single trees, rows of trees and small woodlands. Most of the big forests had already disappeared. In a 9th century text only few forested wilderness areas are mentioned: Fid Mar hi Cuailngi "the great wood in Cooley" (County Louth), Fid Deicsen hi Tuirtre "the wood of Deicsiu in Tuirtre" (around Slieve Gallion, County Tyrone) and Fid Moithre hi Connachtaib "the wood of Moithre in Connacht". Pollen records support these descriptions and it seems that Ireland had already lost most of its forest before the Norman invasion in the 12th century. This however doesn’t mean that the new ruling class took particular care of Ireland’s remaining woodlands. Forests were treated as a cheap resource there for the taking and a substantial amount of Irish timber made its way to England where it was used in all kinds of building projects from houses to ships. It is estimated that by 1600 only 12% of Ireland was covered in forests and continued exploitation brought this down to around 2% by 1800.

In the early 20th century a slow process of recovery began. Since then afforestation, forest management and conservation measures have increased the forest cover to around 11% which is still the lowest in Europe, where the average lies around 30%. The majority of these new forests are commercial plantations made of conifers. Here fast growing and non-native species like Sitka-spruce are the dominating plants and natives like yew and Scots pine only make an occassional appearance. Only around 25% of Ireland’s current forests consist of broadleaves and native trees like oak, ash, birch and hazel make up only half of that percentage.

Remnants of the old forests have only survived in a few small pockets mainly in the west of Ireland, for example in Glengarriff and Uragh in County Cork, Derryclare in County Galway, Old Head in County Mayo and St. John’s Wood in County Roscommon. The only extensive old growth woodland is the one around Killarney which today is part of the Killarney National Park. The park was established in 1932 when the Muckross Estate was donated to the Irish state as a memorial to Maud Vincent and named Bourn Vincent Memorial Park. Since then the area of the national park, now known simply as Killarney National Park, has grown considerably and encompasses an area of over 100 square kilometres protecting not only native forests but also lakes, rivers, mountains and areas of blanket bog.

Some parts of the Killarney woodlands have been around for some 9000 years. After the ice sheets of the last glaciation had disappeared the tundra-like landscape was soon colonized by the first trees: Birch, willow and hazel. The birch especially laid the groundwork for the future forests. The golden leaves that the trees scattered on the ground every autumn were vital to build up soil. In addition birch trees and some of its relatives like the common alder, which is also native to Ireland, form symbiotic relationships with nitrogen-fixing bacteria. These bacteria form nodules in the tree’s root system from where they make nitrogen, a vital nutrient, available to the tree and also leak it into the surrounding soil which makes the ground more attractive to other plants.

As the soil improved these pioneer trees, which grow much faster than the big forest trees, soon established the first woodlands. A glimpse of what these early forests must have looked like can today be found in the Burren, a limestone karst area that covers parts of County Clare and Galway. The Burren woodlands consist mainly of hazel with the occasional hawthorn, holly, ash and willow. Because these species don’t form a thick canopy, the Burren forests support a rich and varied field- and ground-layer. Primrose, wood anemones, bluebell, wild garlic, broad-leaved helleborine and other wildflowers as well as various mosses and liverworts thrive here throughout the year.

After the ground was prepared the giants of the forest appeared on the scene. Scots pine, elm and oak became the dominating species and the pioneer trees were downgraded to the shrub layer in the new forest hierarchy or disappeared. Only some birch forests managed to survive in some damp corners on poor soil. Oak and elm dominated the valleys while Scots pine took over the mountain slopes. Other species like rowan, whitebeam, holly, ivy and honeysuckle thrived in clearings and along lakes and rivers. These primeval forests covered much of Ireland bar the highest mountain tops and extreme coastal fringes and were home to a variety of animals, some extinct, like wolf, brown bear and boar, others like fox and pine marten and numerous birds are still with us.

The oak forest of Killarney are the descendants of these primeval forests. Oak forests form a thick canopy and while the trees are in leaf the forest floor is cast in a permanent twilight. Nevertheless oak forests support a rich biodiversity. Smaller trees like rowan, holly and hazel are often part of an oak woodland and woodrush, bilberry and ferns can be abundant on the ground. A special member of the Killarney oak woods is the strawberry tree, a member of the Lusitanian flora. This evergreen species has become rare and apart from the Killarney National Park, the strawberry tree can only be found in Glengarriff, which is just a few kilometres south of Killarney, and further north in County Sligo. Apart from its distribution, like other Lusitanian species it can only be found on the Iberian peninsula and the west of Ireland, it also has an unusual fruiting cycle. In September and October the Strawberry tree produces clusters of small, wind pollinated, white flowers. Once pollinated it takes a whole year for the flowers to turn into the characteristic red fruits that gave the tree its name. As a result the strawberry tree carries both flowers and fruit at the same time.

The individual oak trees are small ecosystems in themselves. Several hundred species of plants and animals can live in and from an oak tree. Over 200 species of insects alone can make their home on and in an oak. Soil can form in nooks and crevices and host wildflowers and ferns. Other epiphytes like the polypody fern grow directly from the bark and ivy, mosses, liverworts and lichen are also common hitchhikers. The mild and humid climate of Ireland’s south west is a major factor that makes this rich biodiversity possible. Bryophytes in particular cherish the soft weather. A total of 129 of the 162 species known in Ireland thrive in the Killarney woodlands. These forests also have one of the richest variety of ferns in Europe. A total of 52 different species grow here including the royal fern that can reach a height of up to 2 meters.

Both the pedunculate and the sessile oak are native to Ireland. The latter was and still is the more common species. The sessile oak can tolerate poorer soils and because of this can thrive in the fertile valleys as well as on more exposed hillsides with poorer soils. The pedunculate oak is a bit more demanding and chooses only nutrient rich and heavy soils which can be mainly found in the Irish midlands. The only significant pedunculate oak woodlands are therefore located right in the heart of Ireland at the Abbey Leix Estate in County Laois and Charleville in County Offaly.

Both species look very similar and are known to hybridise. The safest way to tell them apart is the acorn, the fruit of the oak tree. The pedunculate oak grows its acorn on a stalk while the acorns of the sessile oak are missing this feature. Both species have always been seen as supreme trees, masters of the forest, which is not surprising. Oaks can become true giants, reaching heights of up to 40 meters and an age of 500 years and more. There is still some discussion on where the oldest oak in Ireland can be found. The most likely candidate stands in the beforementioned Abbey Leix Estate, a pedunculate oak with an estimated age of 700 years. The majority of Killarney’s oak forests however are not older than 200 years and only a few pockets of truly ancient woodland remain. These parts of the forest, like Derrycunnihy Wood, have a very special aura. You can feel the ballast of the years and the trees exude a watchful presence. In these places it is easy to belief that the forest itself is very much a conscious entity.

Reenadinna Wood has an equal respect inducing presence. This community of yew trees stands on an outcrop of limestone that separates Lough Leane from Muckross Lake and is the only surviving yew woodland in Ireland and one of only a few in Europe. The yew was among the first trees to arrive into Ireland after the last glaciation but only became widespread around 5000 years ago. This evergreen plant grows preferably on limestone and chalk and very likely has been a dominating species in the Burren before the arrival of men. Many place names like Mayo (Mhaigh-Eo), the plain of the yews, also suggest that the yew was once far more common than it is today. Today the yew is mainly known as a tree of graveyards. However many of these yews are only distantly related to the native yews that grow in the wild. The majority of the  graveyard yews are the offspring of a chance mutation in which the branches grow more or less straight upwards unlike the wild yews that spread their branches far and wide. The mutation was discovered around 1740 in two plants that grew in the limestone hills of County Fermanagh. One of the unusual seedlings was moved to the landscaped gardens at the Flourenscourt estate. There the young yew prospered into a proper tree and was multiplied through cuttings which were given away to gardens and estates all over Ireland. Eventually this offspring became a popular garden variety and also found its way onto many cemeteries. The mother tree lives on until today in a quiet corner at Flourencecourt. In Reenadinna the wild yews clench their roots into the fissured limestone and the low hanging branches create a cave-like space. It feels eerie and comforting in equal measures. This woodland has been occupying this stretch of land between the lakes for some 4000 years and some of the yew trees have been standing here for 200 years. Yews can live for a long time. On average they have a lifespan of 500 years and outside a forest setting they can reach an even greater age. The oldest yews in Ireland are around 800 years old and stand at the Crom Estate, County Fermanagh and the Fortingall Yew in Scotland, believed to be the oldest yew in existence, has an estimated age of 3000 years.

The eventual decline of the Irish woodlands was a series of unfortunate events. While the early inhabitants, the Mesolithic hunter-gatherers, had little or no impact on the forests, the Neolithic farmers started to remove trees to make space for crops and livestock. Around the same time, some 6000 years ago, a change in the climate triggered the growth of blanket and raised bogs which engulfed vast areas of woodland especially in the west of Ireland. The scot’s pine was one of the first victims of this event and despite some temporary re-colonization of the young peatlands during drier periods the scot’s pine had disappeared from the country by the early bronze age. The petrified tree trunks that can be seen embedded in the peat are a striking reminder of this period.

The elm which had been, together with the oak, one of the main species of Ireland’s early forests also disappeared completely. It is thought that the combination of farming, where elm foliage was used as cattle fodder, and a disease similar to the Dutch elm disease, which affected the species all over Europe in more recent times, lead to the disappearance of this mighty forest tree in Ireland by the 7th century.

By the middle ages the make-up of Ireland’s forest had already changed dramatically. According to pollen record alder had become a dominating species and often grew together with hazel. Both species were widely used, hazel branches were made into wattle for various applications and the nuts provided an important and energy rich food supply. The alder due to its wide girth, which can reach up to ½ meter, was a main source for making shields.

During the 16th and 17th century new species were introduced into the country estates and formal gardens that had become a regular feature of the Irish countryside. Among them were beech, horse chestnut and sycamore, which all have become a common sight in Ireland. Especially the beech has established itself as a forest tree. In Killarney it thrives on the Ross Peninsula where it displays the typical vibrance of a beech forest with its wonderful combination of light green foliage on the trees and a cover of last year’s golden brown leaves on the ground. Another introduced species is the notorious rhododendron. In contrast to its spectacular flower display this evergreen shrub is a constant threat to the native flora. The rhododendron responds extremely well to the local climate and can take over vast areas very quickly. Because of its dense growth it kills off any competing plants quickly and effectively. The National Parks and Wildlife Service with the help of volunteers has been fighting a never ending battle against the rhododendron for many years.

Sometimes however the difference between native and introduced, good and bad, is not as clear. The Norway spruce for example didn’t make it into Ireland after the last glaciation and was recently introduced as a plantation crop mainly for Christmas trees. Cones found in County Antrim and County Mayo however show that the tree was growing in Ireland during an earlier interglacial period some 90000 years ago. This raises the question what native really means. For how long does a species have to be gone from Ireland to become non-native and how long does it have to be growing or living in Ireland to become native? Nature is constantly changing and would do so even without human interference.

At the time of writing Ireland is undertaking huge efforts to reforest the country. Many private initiatives concentrate on establishing new and enlarging existing woodlands by planting the classic broadleaf natives. The Irish state has so far favoured the commercial route and fast growing, mostly non-native conifers. Unfortunately these forests don’t have a long lasting impact because like any crop-plant they are being harvested once they have reached maturity and leave behind nothing but a wasteland. To make a real difference in the current age of climate chance and biodiversity loss the focus should be long term and this doesn’t even need major financial investments. More often than not it will be enough to let nature run wild. The Burren is a prime example for this. To conserve the unique wildflowers of this karst landscape the Burren is being actively managed. To preserve the wildflowers of the Burren traditional farming techniques keep developing woodland in check and encroaching scrub is being cut back on a regular basis. Would we allow these shrubs to prosper the series of events that have been taken place after the last glaciation would most likely repeat themselves. Hazel, blackthorn, hawthorn and other shrubs would be followed by bigger trees and over time the Burren would revert back to a mixed forest. In some spots this process has already begun. The big question is will we be able to step back and let at least in some places the natural process take its course or will we try to keep managing nature like we have always done?


Carsten Krieger, August 2020

All content © 2020 by Carsten Krieger - no reproduction without written permission

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