THE KNOTTY CORE OF EUCALYPTS

Investigations were carried out between 1939 and 1942 in South Australia to determine the amount and distribution of moisture within the trunks of Monterey pine trees (P. radiata Don) and to study the differences from tree to tree. Between 1946 and 1948, additional but less extensive investigations were conducted in the Australian Capital Territory.

Large variations occur within each tree. The vertical distribution of water shows several distinct trends: in some trees the moisture content decreases from the base to a minimum and then increases again towards the top, in others it increases progressively up the tree, while in other trees it decreases progressively with height. The heartwood is a dry region with a moisture content of approximately 45 per cent. The moisture content of the sapwood varies throughout the tree both vertically and laterally.

Big differences in moisture content occur from tree to tree. The wood of young trees is much moister than that of old trees and the moisture content of the trees of fast-growing stands is higher than that of trees of the same age growing on poorer sites. In some stands the wood of dominant trees is moister than that of the suppressed. Interesting seasonal changes occur in the moisture content of the trees, those studied at Mt. Burr containing more water in spring than in autumn.