BSNHS

©BSNHS 2014

This is our only native tree belonging to the family Oleaceae, a family which includes the Olive.

An abundant tree, about our fourth most common tree species, occurring on lime rich soils, less so on sandy soils, common in towns and city parks can grow up to 30m.

The flowers which occur before the leaves often give the tree a purplish colour before they fully open, the pollen being dispersed by wind.  

Ash trees are usually dioecious, but can easily be polygamous.

Up to 100,000 elongated winged fruits (keys) can develop on a single tree often remaining until the following season, they themselves being dispersed by the wind.  

Despite the large number seeds produced many are destroyed by animals before they can grow into seedlings, far more seedlings survive in urban situations where predation is less.  Seedlings can take up to two years to germinate.

Sixty eight species of phytphogus invertebrates are associated with Ash, and 225 species of lichen have been recorded on Ash.  Most characteristic insect is the Ash Bark Beetle (Leperisinus varins) which forms intricate gallery patterns under the bark. The woodboring lavae of the goat moth (Cossus cossus) forms tunnels within the wood, sometimes resulting in stem failure, but also attracting woodpeckers that will chisel into the timber to obtain a tasty grub.

Three types of gall are common on Ash, causing swelling and distortion of flowers and foliage. Flower galling which can affect whole trees is caused by the gall mite (Aceria fraxinivora) which usually attacks the flower clusters soon after they open.

Between 6000 and 7000 years ago pollen records show that Ash was present in southern and central England in consistent amounts and slowly spreading northwards to Scotland and westward to Ireland.

Ash keys  TF

Common Ash

Ash leaf & lichen  TF

Fresh keys with galled flowers(Aceria fraxinivora)

June Tree of the Month - COMMON ASH Fraxinus excelsior