Britain's ancient trees: Walking the trunk route

I don't know anyone who has ever stood in front of an ancient tree without feeling awe-struck." Brian Muelaner is the National Trust's Ancient Tree Advisor and, in an effort to get Britons exploring the history of their natural environment, has put together a list of 10 areas worth visiting for their mature foliage. Spread across the country – from Calke Abbey in Derbyshire to Cheshire's Dunham Massey and Devon's Killerton – the sites offer the public the chance to engage, not just with nature, but also with local history and culture.

"There's the aesthetic element," explains Muelaner. "But these trees are also of huge cultural importance. They provide a link to ancient forests and they have witnessed some of the most amazing national events."

Oddly, for objects of such significance, ancient trees in the UK aren't afforded any kind of protected status. There are no plaques, no official listings. While it's possible to claim that species living on the tree need to be protected for scientific research, the age of the trunk itself isn't enough to guarantee preservation. Outside the National Trust's properties, little can be done to ensure they remain unharmed. Intensive farming, fertilisers and pesticides pose routine threats to "nature's cathedrals".

Hopefully, that situation won't continue much longer. Not long ago, the Woodland Trust launched its Ancient Tree Hunt, encouraging members of the public to upload details of individual trees in their area. When the location and the girth of the tree have been recorded, an expert will be deployed to assess its age. Winter is a good time for this, says Muelaner, because there are no leaves to obscure the body. "You can see the branches and – if you go now – you might even catch the fungi which grow on the trunk in Autumn."

The decision as to which arbours are ancient and which are simply old rests in large part on the species of tree. Birches get off relatively lightly, achieving "ancient" status at the tender age of 200. For an oak to qualify, it must have been growing for at least 600 years, and a yew needs 800. "The best conditions for them aren't the dense forests on the Continent," says Muelaner. "They need space. Our medieval forests were hunting grounds, which were perfect."

Muelaner's favourite spot is populated by sweet chestnuts. "I love the avenue at Croft Castle in Herefordshire. It is thought the trees derived from chestnuts aboard one of the Armada fleet. It's such a wonderful story." A story which, were it not for the ownership of the National Trust, could be lost. "We are one of the only countries in Europe that doesn't list our ancient trees. It is an issue that has been ignored by successive governments. After all, we do it to buildings: why not our forests?"

Brian Muelaner has chosen 10 of the best National Trust sites to see ancient trees. The walks will go live at www.nationaltrust.org.uk on 27 November