A tree is a veteran when it passes from maturity, characterized by a constant annual increment of new wood in the main stem, to the (often prolonged) state when this increment declines.
Veteran trees, by virtue of their age, support a range of scarce habitats including holes and hollows, dead and decaying wood, branch stubs, splits in trunk or branches, flows of sap, aerial water pools and loose, cracked or flaking bark. They are also valued for their great age and prominence in the landscape.
Veteran trees have often fallen victim to ill-judged safety management. As the crowns of veteran trees typically diminish or die-back over time, the mechanical loading on the base is lessened. A veteran tree that appears to be very defective may not in fact be in greater danger of falling than a younger tree.
In managing any tree, safety takes precedence although wider considerations such amenity value or value for wildlife can also be taken into account.
A potentially dangerous tree need not be felled – other measures can often be taken to mitigate risk. These might involve targets, such as play equipment or a bench, being moved out of range of the tree if it fell, re-routing paths or discouraging public access to the target area by ground management.
Davies C., Fay, N. and Mynors, C. (2000). Veteran Trees: A guide to risk and responsibility. English Nature, Northminster House, Peterborough PE1 1UA. Belmont Press. ISBN 1 85716 508 X.