AN EXAMINATION OF SPACING INDEXES FOR EUCALYPTUS-GRANDIS

Data from three replications of a correlated curve trend experiment in Eucalyptus grandis (Hill) Maiden were used to compare spacing indices developed by Reineke (stand density index), O'Connor (S-curve), Yoda (-3/2 power law), and Hart (relative spacing). The experiment tested 12 stand densities ranging from 25 to 6726 stems per hectare, and frequent repeat measurements to age 33 were available. Only data from treatments with stand densities greater than 124 stems per hectare and older than 10 years were included in the study to ensure all stands were approaching a limiting density. Relationships between the indices are developed, and it is shown that they are not independent of age. It is concluded that relative spacing is a useful measure of stand density as both site index and age are incorporated. A value of 0.05 for relative spacing is found as the limiting stand density for E. grandis.