in the external conditions may have accounted for so slow a rate; but it would hardly be safe, with such evidence before us, to allow more than three feet a century as the normal growth of a yew, in which case the Fortingal yew in Scotland, fifty-six feet round in 1769, may have lived more than eighteen centuries; and a longevity in proportion must be accorded to the yews at Fountain's Abbey, or to the Tisbury yew in Dorsetshire, which boasts of thirty-seven feet in circumference. Hence tradition in this case would seem to contain nothing incredible when it asserts that the yews on Kingley Bottom, near Chichester, were on their present site when the sea-kings from the North landed on the coast of Sussex.
It is, however, but seldom that any real aid can be derived from tradition in estimating the longevity of trees. We have even to be on our guard against it, especially when it associates the general claim to antiquity by a specific name or event. In the classical period the tendency was as strong as it is still; and we should look to our own legends when tempted to smile at the Delian palm mentioned by Pliny as coeval with Apollo, or at the two oaks at Heraclea as planted by Hercules himself. Pausanias, traveling in Greece in the second century of our era, saw a plane-tree which was said to have been planted by Menelaus when collecting forces for the Trojan war, whence Gilpin gravely inferred that the tree must have been thirteen centuries old when Pausanias saw it. Tacitus calculated that a fig-tree was eight hundred and forty years old because tradition accounted it the tree where under the wolf nursed Romulus and Remus. Nor was Pliny's inference more satisfactory, that three hollies still standing in his day on the site of Tibur must have been older than Rome itself, inasmuch as Tibur was older than Rome, and they were the very trees on which Tiburtus, the founder of the former, saw the flight of birds descend which decided him on the site of his city. There is of course no more reason to believe in the reality of Tiburtus than of Francion, the mythical forefather of France, or of Brute the Trojan, the reputed founder of the British Empire.
These things suffice to justify suspicion of trees associated with particular names, such as Wallace's Oak, or trees claiming to have been planted by St. Dominic or Thomas Aquinas. Our only safe guide is measurement, applied year by year to trees alike of known and of unknown age, of insignificant as of vast dimensions, and recorded in some central annual of botanical information, facilitating the work of comparison and the arrival at something like trustworthy averages. The experiment, moreover, has not been sufficiently tried whether our oldest trees are capable of an increased rate of growth by the application of fresh earth round their roots, favorable though the case of the Tortworth chestnut is to the probability of such a result. Until, therefore, such statistics are more numerous than at present, we must be content to rest in the uncertainty with regard to the ages of trees which the