A case study of feral olive (Olea europaea) dispersal in northern Victoria. Part I: plant age and growth habit characteristics

S.D. HamiltonA, T. MinottiB, C. O’DwyerB and G. BrodieB,C

A Hamilton Environmental Services, 2345 Benalla-Tatong Road, Tatong, Victoria 3673, Australia.

B Dookie College Campus, The University of Melbourne, Nalinga Road, Dookie, Victoria 3647, Australia.

C Corresponding author.


European olive (Olea europaea L.) has successfully invaded several regions in Australia including the district surrounding Dookie College in northern Victoria. Feral populations of olives have spread from abandoned groves established in the late 1870s but due to a revitalization of the olive industry in the 1990s there is concern about increase in feral olives from this new source. Feral olives do not produce fruit until they are 10 years old so using techniques that can accurately age feral olive trees such as stem diameters or plant height will enable land managers to prioritize the control of reproductive individuals.

This study evaluated ring counting of the stems on European olive trees and it proved to be a successful means of estimating the age of stems, with the estimated age of the widest stem the best estimator of plant age. Significant relationships between estimated stem ages, stem diameter, plant height and width were also established. The relationship between the diameter of the widest stem and estimated age will prove invaluable in developing a broad age structure profile of the feral European olive plants of the district.


Plant Protection Quarterly (2011) 26 (1) 17-21.