Growth of eucalyptus pellita and E. urophylla and effects on pasture production on the coastal lowlands of tropical northern australia

Eucalyptus pellita F. Muell. and E. urophylla S. T. Blake are important timber species which have potential for wood production in plantation and agroforestry systems in humid northern Queensland. This study was established to examine two provenances of each species on a coastal lowland site, using randomised complete block design. Survival, height, diameter at breast height (DBH), bole length and tree form were measured at ages 12, 24 and 39months. The height and biomass of the pasture underneath each provenance plot were also measured at 39 months. Significant differences occurred in most of the tree characteristics at 39 months. Differences in pasture growth, on the other hand, were not significant. Compared with the two E. pellita provenances, the provenances of E. urophylla had superior height and DBH growth but had worse form. Overall, however, both species had high survival, fast growth, satisfactory form, and minimal effects on pasture growth. Although all four taxa appear to be suitable for silvopastoral systems, further trials involving more provenances on a wider rangeof sites are recommended to establish the environmental and economic limits for the use of these species