but it is dying
Really dying? Oh no!
Ancient trees that are over-visited suffer soil compaction around the roots, so this may not be suprising. On the other hand, a very old tree where the wood in the middle has rotted away can actually be very healthy - once that wood has decomposed, there is a lot less weight on top and therefore a lot less strain on teh root system.
But alas, nothing lasts for ever, not even a mighty oak. There may be much older trees, even in Poland, that go completely un-noticed. Where coppicing, whether by man or by nature, has occurred, a single tree may appear to be a series of trees in a highly irregular ring shape. It is disputed whether or not these should be counted as clones or as a single tree.
Is coppicing still practiced? (Or am I steering my own thread away from horticulture and into forestry? Oops - I had better send myself a formal apology). I have seen far too many Scots Pine (bloody Scots - they get everywhere) plantations (Pinus sylvestris) on my (limited) travels, and maybe not quite enough of the deciduous woodland (proabably Oak-Birch, maybe Beech) that should dominate most of the country.
Yes. I did mean that one. Where is it? So I might one day trample the soil over it's poor roots one day.