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Summary Silviculture is the manipulation of forest stand structure and dynamics to achieve specific forest management objectives. In this paper the proceeding contributions from four State forest services about their silvicultural practices in native forests are introduced and reflected upon in the light of likely future directions in Australian forest management. Increasing ecological knowledge and changing social and economic demands on forests necessitate the continuous development and improvement of silvicultural practices. The role of silviculture in delivering sustainable forest management is discussed and some future challenges in native forest silviculture in a post-Regional Forest Agreement environment are presented. Reconciling management of native forests for biodiversity and for production of timber and non-timber products will be a major task, which may only be achieved through silvicultural planning at the landscape level. Further development and refinement of sustainability indicators will ...

Summary The relationship between variation in wood shrinkage and cellulose crystallite width determined by X-ray diffraction was assessed using SilviScan-2 (a system developed at CSIRO for rapid assessment of wood microstructure). Cellulose crystallite width, density and microfibril angle were determined for 600μm wide zones on small wood samples with known tangential shrinkage. The tangential shrinkage measurements included shrinkage to 12% moisture content after reconditioning (MC AR); and a shrinkage differential calculated from tangential shrinkage to 12% MC AR recorded for each zone; and the minimum shrinkage recorded in adjacent wood of similar cambial age. Spearman correlations and forward stepwise regressions showed that the cellulose crystallite width was a good predictor of the shrinkage measures and that density was a minor predictor. Together, cellulose crystallite width and density could explain 75% of the variation in tangential shrinkage for randomly selected locations throughout the tree, ...

Summary Three modelled sequences of estimated average monthly flows of the River Murray were used to study the likely effects of river management on the frequency and duration of flooding of the river red gum forests at Barmah in northern Victoria. One model gave monthly flows in the River Murray at Yarrawonga from 1890 to the present with no regulation or diversions. The second model gave flows with Hume Dam regulation and diversion. The third model gave flow with Dartmouth and Hume Dam regulation and diversion. This corresponds to “current” regulation. The Hume Dam (only) sequence was regarded as the one that corresponded best to the state of the river for which forest flooding data were available. A relation between the average monthly flow (expressed in gigalitres per day) and the percentage of forest flooded was used to transform the historical sequences of monthly flows into the corresponding maximum monthly percentages of forest flooded. This, in turn, was used as input in a grid cell model of the ...

The establishment of commercial tree plantations in Malaysian Borneo began with a progression of various species, including Pinus caribea, Acacia mangium, Gmelina arborea, Falcataria moluccana (for...

SUMMARY The purposes, objectives, and prescriptions for a proposed National Forest Inventory of Australia prepared by an interstate conference are outlined. Production of a forest map and the volume inventory of an area in Victoria on these prescriptions are discussed. The forest map, on 1 mile to 1 in. military map basis, shows forest types, stand size, height and density classes interpreted from air photos. The volume inventory was carried out by a stratified random procedure, using 1-ac. rectangular plots as units. The project proved that the prescriptions for the proposed National Forest Inventory are practicable, and that a descriptive and statistical statement of the forest resources of a comparatively large and valuable area for which there is little information can be made available to a forest service, for planning at the resources level, in a relatively short time by a small but properly managed sample.

Summary This review brings together disparate information about the red gum ecosystem. The climate and soils of the Murray Valley are described, and I outline the impact of river regulation, as well as a number of other human activities, on some of the plants and animals of the region. The review illustrates the fundamental interconnectedness of ecosystem processes, especially in riparian systems. The ecology of red gum regeneration and current silvicultural practices are examined, and the likely future of the red gum ecosystem is discussed. On balance, it would seem that the greatest public good lies in re-establishing and maintaining the natural values of the red gum ecosystem.

Abstract The article by Abdullah Elsadig Ali on “Evaluating the Accuracy of Some Optical Distance Meters” warrants some comments for the benefit of those readers, who may wish to use the published results or wish to carry out similar tests.

Abstract This paper describes the use of photogrammetry for the measurement of objects only a few millimetres in size by using a 35 mm camera in conjunction with a stereoscopic microscope. It is intended not only to point out the attractiveness of the camera-microscope combination in very close-range measurements, but also to illustrate the successful development of a simple observing and computing routine despite the initial lack of any data about the camera-microscope system. The approach, which utilises a stereocomparator and a few elementary equations, demonstrates the advantage gained in close-range photogrammetry by the calibration of a number of parameters. The technique was successful in measuring depths on objects to precisions of 0.01 mm.