Thirteen year results from a spotted gum provenance trial in the Wellington catchment of Western Australia.
Sixteen provenances of spotted gum, including 8 provenances of Corymbia variegata [Eucalyptus variegata], 7 provenances of Corymbia maculata [Eucalyptus maculata] and one provenance of Corymbia henryi [Eucalyptus henryi] were assessed for growth, form and parrot (Barnardius zonarius [Platycercus zonarius]) damage in a trial SW of Darkan, in Western Australia. E. henryi yielded the greatest mean annual volume increment at 13 years old (2.6 m3 ha-1 yr-1), followed by E. maculata (2.5 m3 ha-1 yr-1) and E. variegata (2.1 m3 ha-1 yr-1). Significant differences were found between species and between provenances within species for percentage of single stemmed trees and mean straightness of single stemmed trees. E. variegata yielded the highest average of 15.7% single stemmed trees, E. maculata 11.6% and E. henryi 4.5%. E. maculata yielded the straightest single stemmed trees (4.1 points out of a possible 6) followed by E. henryi (3.7 points) and then E. variegata (3.6 points). E. maculata sustained the lowest incidence of visible parrot damage with 55.9% of trees untouched; E. variegata and E. henryi were similar with only 38.6% and 37.5% of trees undamaged. Correlations between measured parameters and environment at seed source showed strong correlations (r=0.8) between altitude and percentage of single stemmed trees in E. variegata. Within E. maculata, height was correlated with incidence of parrot damage (r=0.8).