What is an ancient tree?

Gnarly. Bent. Ridged. Hollow. Ancient trees are a spectacular sight and the perfect example of living archaeology. They have passed maturity, are very old in comparison to other trees of the same species and are actually in the third and final stage of their life.

Identifying features of ancient trees

Glen Lyon ash

Credit: Ed Parker / WTML

A small canopy

The canopy of the tree will have reduced in size over time through a process known as retrenchment, or growing downwards. This is a natural process in which the crown of the tree and the root system are rebalanced with each other.

ancient tree with wide trunk

Credit: Archie Miles / WTML

A wide trunk

The trunk will be wide in comparison with other trees of the same species. Its size can be greatly affected by factors such as species, soil, climate or growing conditions. The girth could be 1.5 metres for trees such as hawthorn, or five metres for trees like sweet chestnut. With a smaller crown and a wide trunk, the tree is improving its chances of withstanding high winds.

Hollow ancient tree in graveyard

Credit: Ed Parker / WTML

Hollowing

Most ancient trees usually have a hollow trunk, although this isn’t always the case. It can be difficult to identify hollowing unless there is a cavity to look into.

Other common characteristics of ancient trees include coarse or crevices bark and aerial roots growing into the decaying trunks and cavities.

It’s important to note that this isn’t the end of the line for the ancient tree. Although they are in the final stage of their life, and are usually in the process of decay, these trees can live for many, many more years.

How old is an ancient tree?

Ancient trees are defined by their age, particularly when compared to other trees of the same species. There is no set age for a tree to be considered ancient, as different species age at different rates. Birch trees, for example, are fast-growing, and could be classed as ancient at 150 years old, while a yew tree might receive the same accolade at 800 years of age.

The Fortingall Yew in Perthshire, Scotland, could be considered the oldest tree in the UK. Modern experts estimate it to be between 2,000 and 3,000 years old, although some think it could be far older – maybe even 5,000 years old.

What lives in an ancient tree?

Ancient trees are often impressive and complex structures, with plenty of nooks and crannies to harbour rare and specialist wildlife.

Some of the wildlife found living in ancient trees includes:

Chicken of the woods growing on tree

Credit: Jane Corey / WTML

Fungi

Fungi can live on any part of a tree, from the leaves to the roots. They are important as they decompose plant material, releasing the minerals and nutrients, which can then be used by plants and trees. The hollowing of trees occurs when heartwood decay fungi break down the wood that the tree no longer needs, releasing the minerals for the tree to re-use. The fruiting bodies of fungi also provide food for red squirrels, badgers, wood mice, and some beetles and slugs.

stag beetle male on branch

Credit: Arterra Picture Library / Alamy Stock Photo

Invertebrates

There are at least 2,000 species of invertebrates in Britain, all of which rely on dead and decaying wood. As the dead wood habitats in ancient trees change over time, so do the range of invertebrates found in those trees. Saproxylic invertebrates rely on dead or decaying wood for some of their life cycle. Many of these invertebrate species are in decline because of the shortage of deadwood habitat in the UK.

Lobaria pulmonaira on ash tree at Berth Lwyd

Credit: Alastair Hotchkiss / WTML

Lichens

Lichens grow extremely slowly, and ancient trees offer good continuity of environment where they can thrive. Loss of ancient trees can have serious negative consequences for these lichen communities, some of which only grow 1-2mm a year.

Where can I find ancient trees?

The UK is home to an exceptional number of ancient trees, particularly when compared to elsewhere in Europe. Ancient trees can be spotted in a multitude of habitats, including hedgerows, deer parks and even urban areas.

Because the UK is so rich in natural history, there are many areas with especially high concentrations of ancient trees. A visit to one of these might see you stepping back in time, into the remnants of one of the royal hunting forests or medieval deer parks.

Ancient beech tree in the Wye Valley

Visiting woods

Protecting the UK's oldest trees

Ancient trees need special care and protection. There are thousands of ancient trees in the UK and we need your help to find out where they are.

Find out more

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