The climate of the Errinundra Plateau, East Gippsland.  G. R. Featherston, P. C. Fagg and F. Morris.  May 1984.  16 pp. (unpubl.)

SUMMARY

The mountainous regions of East Gippsland are poorly represented by existing climatological stations. During 1971 a rain-gauge and a thermohygrograph were established in a clearing on the densely forested Errinundra Plateau, at 1050 m elevation. Eleven years of data are now available from these instruments.

The mean annual rainfall for the period 1971 to 1981 (inclusive) was 1779 mm, making the Plateau one of the wettest locations in Victoria. The expected annual rainfall based on a correlation with 97 years of records at Orbost is 1770 mm, though total annual rainfall varied from 1187 mm in 1972 to 2720 mm in 1974. On average, the rainfall is fairly evenly distributed throughout all months of the year and, although it is variable, it is reliable enough to prevent drought conditions in most years. Snow is common every winter but usually does not last on the ground for more than a few weeks.

Mean daily maximum temperatures in the period ranged from 20.5°C in February to 6.4°C in July, and mean minimum temperatures from 9.4°C in February to 0.3°C in August. The lowest temperature recorded in the 11-year period was -7.8°C. The Errinundra Plateau has lower maxima and higher minima than nearby Bendoc, yet experiences similar temperatures to Aberfeldy (in the Central Highlands) which is at the same elevation as the Plateau.

The calculated mean annual number of frosts (screen temperature ≤ 2.2°C) was 137, with 68 of these being severe (≤ 0.0°C). This frequency is greater than at stations of similar elevation in Central Victoria and is probably responsible for the demonstrated frost-hardiness of the Errinundra Plateau provenances of Eucalyptus nitens Maiden (shining gum) and E. regnans F. Muell. (mountain ash). There was a mean of at least 14 frosts per month in the period May to September, and frosts were recorded in all months of the year. The mean frost-free period was from 14 December to 13 March (89 days), though large variation occurred in the timing of the first frost of the year.

The high and reliable rainfall may reduce the fire frequency experienced on the Plateau. These factors, together with fertile soils and suitable temperatures, account for the luxuriant forest growth present on the Plateau. The climate per se may not fully account for the presence or absence of certain plant species, geographical isolation probably also being important.