What is an ancient tree?
The older the tree the more valuable it becomes and ancient trees as very old trees are irreplaceable.
An ancient tree is one that has been allowed to grow old and with great age comes great habitats for wildlife. They will have developed lots of niches that wildlife will settle into - such as cavities for bats and birds, and decaying wood for invertebrates.
Ancient trees have passed maturity and are old in comparison with other trees of the same species. They will probably have a wide trunk, which will likely be hollow. And like humans trees shrink with age so they may have a small canopy.
This isn’t the end of the line for the ancient tree, even a dying tree may endure for decades.