In ancient Ireland, sections of alder trunks were used as shields -the wood does not shatter when struck. These were big trunks, and no alders now growing are as big. The trees seem to grow faster, but live for fewer years and never reach the size of giants of old.
The nearest is perhaps an old alder in Breen National Nature Reserve, a natural oak woodland in North Antrim near Armoy. Beside a pond at the entrance is one immense alder, well past its prime but still a fine tree.
Its girth is difficult to measure, since the trunk is clothed in small branches from this tree and associated holly, rowan, and sycamore all growing around or out of the old tree. Ferns and mosses cling to its bark. Including all this, the circumference is over 20’ – almost fit for an ancient shield.