Ash – Fraxinus excelsior

Tree of the Week

23rd September 2019 | Info

Common name: Ash/Common Ash/European Ash

Scientific name: Fraxinus excelsior

Introduction: The Ash is a large deciduous tree and is the third most common tree in the UK. They are large trees which can reach heights of up to 35m and have a lifespan of around 400+ years. 


Leaves: Pinnate (feather-like) leaf. They consist of 3-6 opposite pairs of oval-shaped, light-green leaflets. Each leaf compound has an additional ‘leaflet’ at the end. Unusually, Ash leaves have been known to fall while they are still green.   

Buds: Black and velvety. Arranged opposite each other. 

Bark: Pale brown to grey and develops fissures as the tree matures. 

Form: Grow together to form a domed canopy and can reach heights of up to 35m tall.


Ash trees are typically dioecious (male and female flowers grow on different trees). In spring, both male and female purple flowers appear before the tree’s leaves and grow spiked clusters at the ends of their twigs. The wind pollinates female flowers which then develop into samaras (winged fruits) that are known as ‘keys’ or ‘ash keys,’ between the summer and autumn months. These seeds often will hang onto the tree over winter and into spring when the new leaves appear.

Growth Habit:

Tall trunks and tall, narrow crowns. Ash tree leaves tend to move in the direction of sunlight which sometimes causes the whole crown of the tree to lean in the sun’s direction.

Interesting Facts:

The Ash tree is native to Europe, Asia Minor and Africa and has been cultivated in New Zealand and across the US and Canada. Traditionally, the Ash tree was thought to have medicinal and mystical properties. People would burn its wood to ward off spirits. In the UK, we still consider the Ash tree as a healing tree.

Ecological Importance:

Ash trees provide great ecological importance to the UK. They offer a great number of wild species a perfect natural habitat, and due to its ‘airy’ canopy and premature dropping of leaves, wildflowers are provided with the best conditions to grow in. This, in turn, also helps threatened species such as the brown fritillary butterfly. The tree is also used for nesting by several birds such as Woodpeckers, Owls and Redstarts, while also providing some bird species with a food source. Ash bark also provides an excellent food source for many moth species’ caterpillars due to being covered in mosses and lichens.

Properties of Ash Wood and its Uses:

Ash wood is a hardwood that absorbs shock and is commonly used for making a range of tools and sports handles such as hammers, axes and hockey sticks due to these properties. Ash wood is also used in furniture due to its attractive ‘face’.

Associated Pests and Diseases:

Ash dieback (Chalara dieback of Ash). This fungal disease causes Ash trees to lose their leaves and for its crown to dieback, ultimately leading to its death.

Styling of Ash trees/Where to Find Them:

Ash trees are good city trees as well as good landscaping and shade trees. 


Pruning and Pruning Qualities: Pruning of Ash trees should typically be carried out between late October and early March when it is in its dormant season. Ash trees, on the whole, require little to no pruning as they tend to form well naturally. However, in the case that pruning is needed, the reason that it is required should be considered and may change the time frame in which you should carry out your work. If you want to remove broken, dead or diseased branches then this can be done at any point in the year (as it needs to be conducted straight away) whereas live and well branches should be pruned in winter. Crown reduction, crown lifting and crown thinning are the most common types of pruning for an Ash tree. 

Growth Rate after Pruning: Strong and helps to reduce certain diseases through greater air circulation and sunlight.

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