Growth of young Eucalyptus globulus in plantations after manual defoliation simulating insect herbivory
Abbott, I.; Wills, A.
CALMScience 2(2): 129-132
The impact of three levels of manual defoliation in spring, summer or autumn on growth of young plants of Eucalyptus globulus Labill, was studied over one year. No extraordinary mortality owing to defoliation treatments resulted. Fifty per cent defoliation in autumn significantly reduced initial height growth, unlike 50 per cent defoliation in spring or summer. One hundred per cent defoliation in any season significantly reduced height growth. Basal area growth remained significantly reduced in September 1992 after 100 per cent defoliation in the previous spring or autumn. These findings indicate that single 50 per cent or less defoliations of E. globulus by insects should be tolerable in spring or summer, but not in autumn, and that 100 per cent defoliation is unacceptable at any time.