From a news report last week.
“One of the oldest trees in Wales which was probably planted 1,000 years ago as a boundary marker along Offa’s Dyke has fallen down.
The Buttington Oak was spotted collapsed in its field two miles from Welshpool in Powys by a man nicknamed the “tree hunter”.
Rob McBride said he was sad to see such a significant tree grounded.
The tree’s girth measured 11m, which made it about 1,000 years old, he added.”
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The problem is that none of our really old trees have any legal protection. Old buildings of this age would be listed, yet they can be rebuilt.
Ancient and Notable Trees need to have a protected root area and the soil left alone within this zone.
Is it significant this Welsh tree appears to have cultivated soil and crops under the crown and up to the trunk?
In my travels I see many trees within cultivated fields that are dying due to the soil ploughed up to the trunk, or excess nitrogen application destroying the essential surface roots. It is a fallacy that tree roots go deep down into the soil; most are within the top few inches and spread widely, often great distances beyond the crown spread. 
                                                      @THETREEHUNTER