Some yews may be older still, so an even more accurate sign of a place having Neolithic significance.
Pinched from my post on another forum:

Allegedly, one churchyard yew in Wales dates from 2000 BC.
http://216.239.37.100/search?q=cache:VrQF7qedRp4C:www.walesdirectory.co.uk/history.htm+neolithic+yew&hl=en&ie=UTF-8

It is suggested that the ability for seedlings to fuse with the original effectively makes yews immortal. “Europe’s oldest”, in Scotland, (again, with a bronze age barrow near to it) is claimed to be 9000 years old!
http://www.cvni.org/articles/august2001/yew.html

One speculation has it that “the research carried out on ancient yews by Allen Meredith has shown that the original temples themselves were built on these sites because of the presence there of what was already an ancient tree, which symbolised everlasting life or life after death to the Celts. By Allen Meredith's reckoning, one can date the site of the original temple to be Neolithic where the church is to the south of the yew.”
http://www.treeman.co.uk/ (click on oldest yews). I think this is suggesting that current old yews may imply previous revered old yews. If this was right, a mere “stripling” present day yew of say 1500 years could be a pointer to Neolithic significance of a site.