Inter‐tree competition and small‐scale pattern in monoculture of Eucalyptus obliqua L'Herit

The pattern of spatial arrangement of trees at scales up to 20 m is examined in 12 plots of even-aged monoculture of tall-open Eucalyptus obliqua L'Herit. forest, aged 30–57 years, in Tasmania. In general, trees were randomly arranged on the plots. In four plots there was a tendency towards regular spacing amongst the 50% largest diameter trees of the plots, these trees being the more successful competitors. There was evidence that this occurred simply because crown spread prevents dominant trees being too close together. There were slight tendencies in some plots for larger trees to be further from their nearest neighbouring tree than smaller trees and to have smaller nearest neighbours than smaller trees. These results are considered in relation to suggestions that competition in monoculture should impose spatial regularity on successful competitors and that dominant trees suppress near by trees. It is suggested that inter-tree root grafting or variability in the shape of root and crown systems may reduce the tendency for these effects to apply, consistent with the results of the present work.