The Ash is one of our commonest native trees. Historically it has been an important source of wood wherever a combination of strength and flexibility are required, from tool handles to frames for early motor cars, coaches and aircraft. It has always been useful for sports equipment. The first skis were made of ash. Modern uses include rowing oars, hockey and hurley sticks, handles for garden tools.
When an Ash tree is cut down, shoots spring up to form a coppice. This is a very useful feature. The young straight shoots can be used for basket-work (when heated with steam they are easily bent). Older shoots make good walking sticks, and in former times it was the preferred species for warriors’ and hunters’ spears.
The canopy of a mature Ash tree, showing its rather open nature. Trunks are smooth when young, becoming fissured when mature. Image: John Grace.
Its leaves are eaten by free-roaming ponies in the New Forest, Hampshire, and throughout Europe the plant was much used as fodder in former times.
The tree can be up to 20 metres tall but usually it is less, and sometimes only a few metres in exposed coastal conditions. It is not especially long-lived. Mature trees can be 150 years old, or perhaps more when they have been repeatedly coppiced. It has also been an important hedgerow tree throughout Europe, and old trees are often seen around villages, a testament to its value as a source of material in rural life. Ash in hedgerows might be very old if the hedges are maintained in a traditional manner, but alas! very few of them are, and many hedgerows have been removed to enable ‘efficient’ farming practices.
A very old Ash tree at the Bargany Estate, near Girvan in Ayrshire, pictured in May 2023. This one seems to have been repeatedly coppiced and has obviously endured storms. Sorbus aucuparia is growing epiphytically in its branches. Image: John Grace.
It occurs in mixed deciduous woodlands with other trees. In the cool-wet North-West of Britain it is a component of woodlands with oak and bracken; in the warm-dry South-East it may appear as a main component of woods with maple (Acer campestris) and Dog’s Mercury. (Mercurialis perennis). It grows on all kinds of soil, but has a preference for damp fertile soils of high pH. It appears in calcareous districts, especially on limestone pavement. Good examples are the Derbyshire Dales, The Burren in Western Ireland and in Scotland the Rassall Ashwood, Loch Kishorn, Ross-shire where trees are rooted among scattered blocks of limestone pavement covered with moss.
Budbreak and the unfurling of leaves. The leaves are pre-formed in the buds, so that the
early growth is very fast. Images: Chris Jeffree.
Its flowers appear early (April). A little later (early May) its black over-wintering buds open up, and extension growth is extremely rapid. The leaves are quite distinctive, and it is one of the easiest trees to identify. The urban specimens I see around Edinburgh are currently (late May) in almost-full leaf whilst all other species have been green for a few weeks. There is a folk-saying that goes like this:
“If oak is out before the ash, then we’ll only have a splash,
If the ash before the oak, then we’ll surely have a soak”.
A mainly female inflorescence which will go on to develop into the familiar ‘ash keys’.
Image: Chris Jeffree.
Actually, oak is almost always in leaf before the ash, and ash is usually the last of all British trees to show its leaves. Perhaps in the 18th century the rhyme provided a useful long-range weather forecast, but not now. The UK met office researchers have examined modern records and the folklore has been adamantly refuted. Oak is much more temperature sensitive and with climate warming its buds are opening sooner.
Male flowers at anthesis. The dark maroon structures are the anthers. The cream colour is where the anthers have opened to release pollen. At higher magnification you can see the individual pollen grains. Images: Chris Jeffree.
I have always been confused by its flowers. Alan Mitchell says: “Total sexual confusion: some trees all male, some all female, some male with a few female branches some vice versa…” Chris Jeffree’s images in this blog have helped me to understand what’s going on. There are no petals: the flowers are wind-pollinated. If you start to feel itchy and begin sneezing in the spring, it may be that you are allergic to Ash pollen. By now (late May), the flowers have withered and the young fruits will soon be seen. They develop rapidly and form the characteristic bunches known as ‘ash keys’. Later, these fall to the ground when the embryos within are still developing. Germination occurs one or two years later.
Two images of Rassall Ashwood, Loch Kishorn, Ross-shire, taken in the 1980s. Images: Chris Jeffree.
Seeds and seedlings are preyed upon by mice, voles and rabbits, and young plants are browsed by deer, although they are not a favourite food. Slugs avoid Ash seedlings. The sharp decline of rabbits caused by the viral disease myxomatosis in the 1950s may have helped regeneration of Ash.
The fruits of Ash are colloquially called ‘keys’ but botanically each unit is a samara, a fruit with a flattened wing of fibrous, papery tissue developing from the ovary wall. Attribution: Pleple2000, CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons
But Ash is currently under attack. Ash trees throughout Europe are suffering from an infection known as ‘Chalara ash dieback’ caused by the fungus Hymenoscyphus fraxineus (formerly Chalara fraxinea) which comes from eastern Asia. Fungal spores are widely distributed in the wind and the disease has been spreading fast. At first, leaves turn black and then whole branches die. It can kill young and coppiced ash trees quite quickly. Older trees can resist it for some time until prolonged exposure and perhaps attack by other pathogens finally kill them. The situation is worse in European countries, and what they have been experiencing is perhaps a foretaste of what will happen in the UK. As a consequence of this disease, Ash is considered seriously ‘Threatened’ in Hungary and Threatened or Near Threatened in Norway, Sweden, Finland, Albania, Serbia, Montenegro, and Spain. Overall, this species is therefore listed by the IUCN (The International Union for Conservation of Nature) as ‘Near Threatened’. Useful information about the symptoms, and how to report a suspected outbreak, can be found here.
Records of Ash Dieback from the Forestry Commission. Useful information about the symptoms, and how to report a suspected outbreak, can be found here.
There is a second deadly enemy of Ash. The Emerald Ash Borer (EAB) is a beetle that has infested and destroyed many Ash trees in the USA. It hasn’t reached us yet, but it has been found in Russia and Ukraine. We may expect it to arrive soon. The UK agency DEFRA has said there is ‘a contingency plan in place to guide a national response should the pest be introduced’. Further information, including what to do if you think you have seen it, can be found here, along with photographs.
Infected Ash trees showing stages of dieback at Dalkeith Park. Image: Chris Jeffree.
Oliver Rackham, in his little book The Ash Tree, is critical of Government and bureaucracy. He says “Imports of ash trees should have been banned in the 1990s, as soon as Ash Disease was detected in Europe.” He points out that ash seedlings were being imported from Germany and the Netherlands at a rate between 1.5 and 3.5 million per year.
I would hate to see Ash eradicated by disease. Elm and Ash formed the landscape in which I grew up, and the local Ash wood where we picked bluebells later became a Site of Special Scientific Interest (SSSI). Years later when I was a student we spent happy days in the Ashwoods of the Derbyshire Dales, and our degree course took us to the limestone pavement of the Burren in Ireland where Ash forms a scrub.
Ash woodland on limestone at Glen of Clab, Burren, south west Ireland. Image: Chris Jeffree
Global distribution of Fraxinus excelsior. Northern limit is determined by winter cold. Southern limit in Europe is probably determined by lack of water. From GBIF.
References
Khela S & Oldfield S (2018). Fraxinus excelsior. The IUCN Red List of Threatened Species 2018: e.T203367A67807718.
McKinney LV et al (2011) Presence of natural genetic resistance in Fraxinus excelsior to Chalara fraxinea (Ascomycota): an emerging infectious disease. Heredity 106, 788-797.
Mitchell A (1974) A field guide to the trees of Britain. Collins.
Rackham O (2014). The Ash Tree. Toller Fratrum, Dorset: Little Toller Books. pp. 25–6. ISBN 978-1-908213-14-3.
Thomas PA. (2016). “Biological Flora of the British Isles: Fraxinus excelsior“. Journal of Ecology, 104, 1158-1209.
Notes
1.There is an ornamental species Fraxinus ornus, called Manna Ash, which is naturalised in some places. Its leaves are like those of F. excelsior but it has showy flowers which appear after the leaves.
2.Fraxinus belongs to the Olive Family, Oleaceae. Other members are Forsythia, Jasminum, Syringa, Ligustrum.
©John Grace
Botany in Scotland 