Frost hardiness of commercial Eucalyptus species at different elevations
Six Eucalyptus species, E. regnans F. Muell., E. delegatensis R.T. Bak., E. globulus Labill., E. nitens (Deane & Maid.) Maid., E. pauciflora Sieb. ex Spreng, and E. grandis Hill ex Maid., were sampled for determination of frost hardiness in March (late summer) and August (late winter) 1985 from trial plantings at four elevations in southern Tasmania. In March, there was a statistically significant difference between sites, but not between species or provenances. In August, significant differences between species, and for E. delegatensis between provenances, had developed. The species ranked in order of increasing frost hardiness as follows: E. regnans < E. grandis < E. globules = E. delegatensis (Maydena provenance) < E. pauciflora < E. nitens < E. delegatensis (Guildford provenance). Greatest frost hardiness was developed at the 60-m site (elevation), followed by (in decreasing order) the 650-m site, the 440-m site, and the 240- m site. This order corresponded to the minimum temperatures experienced at the sites. Conversely, greatest growth occurred at the 60-and 240-m sites followed by the 440-m site and then the 650-m site, corresponding to decreasing maximum temperatures. It is argued that good growth and productivity are possible on quite frost prone sites, provided suitable provenances are selected for planting.