Variation in Some Central Victoria Populations of Eucalyptus viminalis Labill

Abstract

E. viminalis occurs over a wide range of rainfall conditions and soil types in south-eastern Australia and exhibits considerable variation in form. A study of 11 populations in central Victoria shows that at moist, well-drained sites mature trees are tall and smooth-barked, have three-budded inflorescences, and produce large leaves and fruits. At drier sites trees are shorter and more rough-barked, sometimes have inflorescences with buds numbering from three to seven, and tend to produce smaller leaves and fruits.

The results of a comparison of fruit collections made in successive years indicate that capsule size can vary significantly at any one site. It is suggested that the size differences may be related to soil moisture availability. Furthermore, within the crown of any one tree, leaf size was found to vary, leaves from the upper part of the crown being significantly smaller than leaves from the lower crown.

A field transplant experiment involving five populations showed that environmental factors can markedly affect seedling growth and leaf morphology. However, population differences in growth rate, tolerance to drought and waterlogging conditions, and lignotuber development appear to be in part genetically based.