Thinning dense thickets of advanced natural radiata pine regeneration in north-eastern Victoria.  G. Minko.  July 1987.  9pp. (unpubl.)

SUMMARY

Dense thickets (greater than 10,000 stems ha^-1) of natural regeneration are a feature of many plantations of radiata pine in Victoria. Thinning of such thickets appears necessary to prevent stem collapse, to ensure efficient extraction of produce and to optimise the yield of sawlogs.

The feasibility of thinning thickets of advanced natural regeneration was evaluated in the Ovens Plantation, North-eastern Victoria, in 1987. Four thinning treatments were applied to 22 year-old regeneration where stocking varied between 4,000 and 7,000 stems ha^-1. Three of the treatments involved stem injection with herbicides, whilst the fourth treatment was felling by chainsaw.

The results of the study show that, on wind-firm sites (Site Index less than 22 m), it is possible to economically thin these advanced thickets by basal stem injection with herbicides. The number of dominant trees remaining after treatment will generally exceed 500 stems ha^-1 which is sufficient to produce a final crop of trees with sawlog potential. Released trees are likely to retain their wind stability and straight form.

Alternative options for thicket management are discussed.