The effect of time of sowing on eucalypt regeneration following direct sowing onto disturbed soil in the High Elevation Mixed Species forests of East Gippsland

Abstract

SUMMARY Time of sowing may be a factor contributing to the success of regeneration in high elevation mixed species (HEMS) forest. This study was undertaken to determine the best time of sowing for the germination, survival and early growth of seed sown on mechanically disturbed seedbeds. Plots were raked and sown with a predetermined quantity of seed during the period of January to August 1991 and 1992, and germination, survival and height growth were monitored monthly up until July of the year following sowing. • Germination patterns varied widely with species, site and timing of sowing. Peaks of germination occurred in autumn and early spring with some germination in the mild summer of the year 91/92. Winter germination was limited and subject to heavy mortality. Survival of germinants varied with time of germination, site and season. Winter mortality following autumn germination was heavy. Survival following spring germination varied with the season, but was clearly superior to that of autumn germination in the circumstances of the present study. Summer germination under mild weather conditions followed by rapid autumn growth led to reasonable rates of survival. • While affected by browsing, height growth of the tallest seedling per plot was similar for both autumn and spring germinants. Height growth was very poor in coupes where plots were hand-raked and sown approximately one year after the surrounding areas had been regenerated. For the site preparation sequence followed in this study, the success of different sowing times varied between sites. However, on balance, winter sowing followed by spring germination gave the greatest survival with height growth being equal to or greater than autumn sowing. These results support the current prescription for time of sowing of HEMS reforestation coupes.