Establishment of indigenous eucalypts in dieback areas of Mullungdung State Forest, Yarram Forest District. 1. First progress report. Survey of experimental areas during February and May 1978 following site preparation and sowing in February and June 1977 respectively.  F. G. Nuemann, I. W. Smith and R. Jolly.  March 1979.  30 pp. (unpubl.)

SUMMARY

The results are reported of surveys during February 1978 (484 four-milliacre plots on a 15 x 30 m grid) and May 1978 (810 four-milliacre plots on a 5 x 10 m grid) for assessment of seedling stocking density and other factors in two experimental areas that had carried eucalypt forest variously affected by dieback in Mullungdung State Forest near Yarram. Both areas had been clearfelled during March 1977 and subdivided into research and demonstration areas. Research areas were either burnt or cultivated and half handsown with indigenous eucalypts, whereas the demonstration areas were burnt and sown throughout. Sowing was at the rate of 25 x 10⁴ viable seeds per ha; the seeds had been treated with DDT insecticide and thiram (TMTD) fungicide. This treatment was later shown to significantly reduce germinative capacity and seedling root development.

Fifty-eight percent of the plots within the experimental areas surveyed during February supported healthy seedlings, though only half of these pots were stocked with more than four seedlings. Seedling stocking density appeared unrelated to burning intensity. Within research areas surveyed during May, seedling stocking density was substantially higher on cultivated and sown plots than on those burnt and sown or on all unsown plots. Experimental area plots infected with Phytophthora cinnamomi (PC) root disease, and those established on previously severe dieback forest sites were more intensely stocked than PC-free plots. Low seedling mortality on PC-infected plots suggests that the fungus had not been active during the preceding spring/summer period, which was substantially drier than average. This view was supported by the finding that the population index values for PC since germination had been low and the frequency of isolation of the fungus had much declined from pre-sowing levels. Burning appeared to have no effect on reducing the isolation frequency of PC.

The seedlings, averaging 38 mm in height and carrying between 7-8 leaves, were generally free from damage by insects or leaf fungi, though many had been browsed by herbivores. Healthy lignotuberous growths were fairly widely distributed in the experimental areas.