Radiocarbon Age-Determinations From Lignotubers

Abstract

Large plate-like lignotubers formed by Eucalyptus botryoides Sm. were examined at a site on the south coast of New South Wales. Circumstantial evidence suggests that they are of great antiquity, yet ¹⁴C activity measurements of samples taken from lignotubers or associated stump wood corresponded to young ages, and it is clear that low durability of wood from these lignotubers prevents an accurate age determination by ¹⁴C dating methods. Ages of up to 600 years B.P. were obtained, but only from carbonised wood fragments associated with, but not connected to, decayed portions of large lignotubers.

The differences in ¹⁴C activity found in samples from the intact lignotubers could not be interpreted clearly in terms of sequential growth periods for them. ¹⁴C activity differences between samples from two lignotubers are difficult to explain on the evidence available.

Conversely, age sequences of up to 540 years were obtained from lignotubers of Eucalyptus coccifera Hook f., from Snug Tiers, near Hobart, Tasmania. The wood from these lignotubers has been well preserved. Possible reasons for these differences in lignotuber preservation will be discussed further.