Environmentally sound timber harvesting: logging guidelines, conservation reserves and rehabilitation studies

Timber harvesting guidelines formulated for north Queensland rainforests allowed economically viable harvests with minimal ecological impact. Harvesting procedures sought to minimize soil erosion, silting and turbidity in steams, destruction of trees in the residual stand, and disruption of natural habitats and processes. Forest officers selected the trees to be harvested, indicated the direction of felling, and supervised the design, construction and drainage of roads. The long term impacts of harvesting are not certain, so it is desirable to reserve some areas for conservation and monitoring. Existing data may help to indicate priority conservation areas, but errors and anomalies may be misleading. Some strengths and weaknesses of such data and techniques are discussed. Degradation by soil erosion and weed infestation can be difficult and expensive to rectify. Without intervention, such areas may revert to high forest only after several decades, resulting in lost timber production. Reduced floristic diversity and inferior habitat for wildlife also imply substantial non-tangible losses. Rehabilitation may not be financially viable unless industrial plantations are feasible. Thus degradation should be avoided by adopting harvesting practices suited to the silvicultural characteristics of the forest, and by minimizing soil loss and invasion by weeds. In short, prevention is better than cure.