Research on the silvicultural and environmental effects of harvesting at Maramingo and Reedy Creek Pulpwood Demonstration Areas, East Gippsland. Progress to November 1980.  R. H. Loyn.  January 1981.  43 pp. (unpubl.)

SUMMARY

This report summarises research at two pulpwood demonstration areas in east Gippsland before harvesting (1976) and afterwards to 1980. The areas are at Maramingo (a dry site with sandy granitic soil) and Reedy Creek (a wetter site with dark brown clay-loam on Ordovician sediments). Subjects discussed include aspects of eucalypt and understorey regeneration, bird and mammal habitat, pathogens, biomass distribution and soil erosion; other subjects are mentioned more briefly.

Eucalypt regeneration following harvesting was generally good on both areas and was not correlated with seed-tree density (from 2 to 15 per hectare). It is likely that late and patchy burns and extensive soil disturbance allowed considerable regeneration from seeds in felled crowns, masking any effects of seed-tree density. Regeneration was equally good on burnt or unburnt (disturbed) soil at Reedy Creek, but at Maramingo the late burn killed many seedlings and better stocking was obtained on disturbed, unburnt soil. No eucalypt species failed to regenerate though the proportion of each among the regeneration differed to a certain extent from the composition of the original forest or retained seed trees, with Eucalyptus sieberi L.A.S. Johnson (silvertop) becoming more common in both areas.

Understorey vegetation, after an initial reduction, regenerated well on both areas, with little change in total species composition or in vegetation pattern. However, abundance of some individual species increased to levels greater than before harvesting whereas others decreased. Some species were favoured by burning whereas others were not. Introduced species (weeds) were initially a very minor component of the vegetation at both areas; they remained so at Reedy Creek (confined mainly to tracks), but at Maramingo three species participated in a general proliferation of small herbaceous plants. By 1980, cover of understorey vegetation at Maramingo was greater than before harvesting. At Reedy Creek, understorey, which was initially very dense, had not attained original levels by 1980. Regeneration was good on snig tracks but slow on landings.

Bird populations were reduced by harvesting in both areas, but some new species entered the harvested areas. Other forest birds remained and some that forage on open ground increased. Others began to increase as understorey regenerated, or foraged in retained trees and patches of advanced regrowth. The only introduced birds observed were occasional European goldfinches (Carduelis carduelis). Most species remained in each area, but some became confined to unharvested parts. The rarest species observed, glossy black-cockatoo (Calyptorhychus lathami), initially disappeared from Maramingo after harvesting but some were feeding in retained casuarinas again in January 1980.

Small native mammals were initially scarce at Maramingo and were abundant Reedy Creek. At Maramingo they became more common after harvesting, especially in unburnt parts. At Reedy Creek they were reduced initially though some individuals survived in unburnt patches and began to increase as understorey regenerated. Arboreal mammals were scarce in both areas and more were seen after harvesting them before; they were feeding in retained trees, though all except the pygmy possum appeared to be moving between these trees and adjacent unharvested forest. Large terrestrial mammals continue to feed and camp in the harvested areas. Four introduced species were observed: rabbits became common at Maramingo; a few house mice were trapped at Reedy Creek in 1980; and foxes and dogs were recorded in both areas.

Pathogens including Phytophthora cinnamomi Rands (cinnamon fungus) were present in both areas, and some E. sieberi seedling deaths at Reedy Creek were associated with P. cinnamomi. A few retained trees have died from various causes. At present, dieback of these trees is not a serious problem.

Biomass of trees and understorey were estimated at Maramingo during harvesting. The total biomass was estimated at 344 t ha^-1, of which 94.6% was in the forest overstorey. The proportions of each component in the overstorey were: stem wood 60.1%, stem bark 15.8%, branch wood 16.5%, branch bark 3.9%, twigs 2.0%, and leaves 1.7%. Results for nutrient distribution in the biomass are not yet available.

Soil erosion was not a severe problem in either area, and was negligible at Reedy Creek. Some erosion took place on the sandy soils at Maramingo, especially along snig tracks and in burnt areas. Erosion on snig tracks was reduced by hand barring but not by machine barring. Some implications for management, and limitations of the studies, are discussed.