Ash

Common ash
Fraxinus excelsior

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Common ash belongs to the genus Fraxinus and is a member of the olive family (Oleaceae).

Common ash (Fraxinus excelsior) is a large deciduous tree growing up to 45m and flowering April to May.

Lifespan: Ash can live up to 400 years but it is thought that coppiced trees can live many hundreds of years more.

 

Characteristics

Bark is pale grey and fissures with age. Twigs are smooth with obvious black, velvety buds.

Ash leaves are compound, so each leaf is made up of three to six pairs of oval, pointed, toothed leaflets with one terminal leaflet. The leaves are in opposite pairs each measuring up to 35cm.

Ash is dioecious: male and female flowers are found on different individual trees, but a single tree can also be of mixed sex with male and female flowers on different branches. Purple flowers form in spiked clusters at the tips of twigs and appear before the leaves. Male (left) and female (right) flowers are pictured below.

Ash is wind pollinated and the flat oblong seeds become single winged keys that hang in bunches. The seeds mature August–September and fall from the tree between winter and early spring.

Ash tree
Ash flowers

Distribution

The common ash is widespread throughout Europe and native to the UK. Ash woodland accounts for 13% of broadleaf woodland in the UK.

Ash grows best on moist to well-drained, neutral to base-rich fertile soils.

In coppiced form the ash can reach a considerable age and is often found in ancient semi-natural woodland. The tree is also a frequent ‘gap coloniser’ of beech woodland.

Human value

Ash wood is pale, clear, strong and durable in dry conditions. Its flexibility enables it to withstand pressure, shock and splintering.

Ash has become popular for good quality furniture and is also used in laminates and plywood. Ash is the only British native timber that has never been replaced by an imported substitute.

Ash coppices well and regeneration is often prolific. It makes excellent firewood. It has long been used for tool handles, coach building and sports equipment such as hurleys for the Irish sport of hurling.

“Oak before ash there’ll be a splash; Ash before oak there’ll be a soak.”

In spite of this old saying the ash is usually our last native tree to come into leaf.

Ash leaves
Ash trees

Wildlife value

Ash is an important tree for wildlife. It is very long lived, enabling it to support many specialist deadwood species such as the lesser stag beetle and hole nesting birds such as owls and woodpeckers.

Ash woodland has a light open canopy which encourages a rich ground flora of dogs mercury, bluebells and ramsons. Often it is accompanied by a hazel understorey.

The alkaline bark of ash supports numerous epiphytic lichens and bryophytes and also attracts snails. Its leaves provide food for many moth species including the barred-toothed striped, the coronet, the brick, the centre-barred sallow and the privet hawkmoth. Birds such as the bullfinch eat ash seeds.

Upland mixed ash woodlands are a priority habitat under the UK Biodiversity Action Plan and form one of the richest habitats for wildlife in the uplands. They support many rare woodland flowers such as dark red helleborine, Jacob’s ladder, autumn crocus, lady’s slipper orchid and threatened butterflies such a the high brown fritillary, the dingy skipper and the grayling.

Management

Ash is a light-demanding pioneer species able to rapidly take advantage of open space. It is able to grow at elevations of 400m above sea level, but prefers lowland areas.

Ash seeds have multiple dormancy and only germinate in their second spring after periods of cold and warmth. Seeds can be collected and sown in late summer while still green. Alternatively, collect seed in October and pretreat for 18 months, sowing March to April.

Ash is frost tender but, because it comes into leaf so late, it usually escapes frost damage. It requires shelter when young.

Ash trees can be vulnerable to a variety of root and butt rots that can lead to thinning foliage and a decline in health. Ash can also suffer from ash dieback which may result in the death of branches and limbs. The Ash bud moth may cause wilt, dieback and forking in young trees.

Ash logs

Illustrations © Reader’s Digest Association, Inc.
Woodland photographs © Debbie Cotton
Ash log photographs © Forestry Commission