Silvicultural research for sustained wood production and biosphere conservation in the pine plantations and native eucalypt forests of south-eastern Australia

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Summary In the last decade, greatly increased public and political awareness of the need for biosphere conservation has placed strict controls on the productive use of Australia's already limited forest resource. The challenge is considerable. Ultimately, it could mean that much of Australia's native forests will no longer be available for wood production either directly or indirectly through conversion to plantations of pine of eucalyptus. This paper describes how the Department of Conservation and Environment in the State of Victoria is meeting this challenge for forested public land. Specifically, it addresses silvicultural research: to sustain wood production in second and subsequent rotations of pine plantations; and to balance sustained wood production and ecosystem conservation in native forests. From a review of field trials and fundamental studies motivated by reports of a “2R-decline” in wood production on sandy soils in South Australia, it is concluded that a serious irreversible decline is unlikely to be caused by pines in themselves. It is more likely to be caused by silvicultural practices that compact the soil and, especially in the case of sandy soils, deplete soil organic matter. A reversible decline is most likely to be due to a water X nutrient interaction related to water consumption by weeds and nutrient losses from practices such as slash burning. In native forests, Victoria has embarked upon a silvicultural investigation of a magnitude and complexity never before attempted in Australia. The main issues are the use of the clearfelling silvicultural system, and harvesting of residual wood mainly for wood chipping and conversion to pulp and paper products. Organisational arrangements for planning, managing and monitoring the research, with strong community involvement, are described together with the research studies which are based on three main systems; namely: the forest ecosystem; the forest management system; and the socio-economic system. It is concluded that success will require the achievement of high scientific objectivity and strong community involvement.