Silvical characteristics of messmate stringybark and narrow-leafed peppermint under partial cutting conditions.  II: Factors influencing germination, survival and early growth.  J. D. Kellas.  August 1994.  33pp. (unpubl.)

SUMMARY

This report presents the results of a silvicultural study of messmate stringybark and narrow-leaved peppermint under five stand treatments representing current and potential management options for the Wombat Forest in west-central Victoria. The study compared five stand treatments; clearfell, and three intensities of partial cutting (single tree selection, low intensity shelterwood and high intensity shelterwood) and a control over a 6.5 year period. Within each of these stand treatments, germination and survival were studied on three seedbed preparation methods (bare mineral soil, cultivated mineral soil and burnt) subject to natural seedfall and artificial sowing in March and May 1984.

Germination commenced approximately 6 weeks after sowing, with between 20-30% of seeds observed to germinate during the period to October 1984. However, mortality resulted in the deaths of more than 86% of germinants over 6.5 years. At the conclusion of the study, the numbers of established seedlings was not influenced by seedbed preparation method or time of sowing, but there was a trend suggesting survival decreased with increasing residual basal area.

The seed applied to the plots was a mixture containing equal numbers of messmate stringybark and narrow-leaved peppermint seeds. However, after 6.5 years, messmate stringybark seedlings were generally more common and taller than narrow-leaved peppermint seedlings.

Seedling mortality occurred throughout the study with most (65%) occurring within 10 weeks of seedling germination. The major causes of mortality were frost heave and damage associated with freezing, Cutworm damage, damping off and 'summer drought'. Of the total mortality, almost 25% could not be explained.

Natural seedfall following harvesting and seedbed preparation resulted in adequate regeneration stockings under the various stand treatments, both on prepared seedbeds and within each stand treatment. This indicates that with an adequate supply of eucalypt seeds, either supplied by natural or artificial sources, combined with a receptive seedbed, successful regeneration of messmate stringybark and narrow-leaved peppermint could be obtained under a wide range of retained overwood conditions.

Further study will be required to determine the appropriate levels and period of retention of residual overwood competition for optimum seedling development and growth.