23 resultados para 091210 Timber Pulp and Paper


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Rainforests in eastern Australia have been extensively cleared over the past two centuries. In recent decades, there have been increasing efforts to reforest some of these cleared lands, using a variety of methods, to meet a range of economic and environmental objectives. However, the extent to which the various styles of reforestation restore structure, composition and ecological function to cleared land is not presently understood. In this study, we develop and apply a method for quantifying the structural attributes of reforestation sites in tropical and subtropical Australia. The types of reforestation studied were plantation monocultures, mixed-species cabinet timber plots, diverse restoration plantings and unmanaged regrowth. Two age classes of reforestation were examined: 'young' (5-22 years), incorporating sites from all categories, and 'old' (30-70 years), in which only monoculture plantations and regrowth were represented. A total of 104 sites were surveyed including reference sites in intact rainforest and pasture. Intact rainforest was characterised by a suite of complex structural features including abundant special life forms (vines, epiphytes, hemi-epiphytes and strangler figs), a dense stand of trees in a range of size classes, a closed canopy, a shrubby understorey and a well-developed ground layer of leaf litter and woody debris. These features were lost on conversion to pasture. While all types of reforestation returned some elements of structural complexity to cleared land, young plantation monocultures, cabinet timber plots and young regrowth had a relatively simple structure. These sites typically had a low density of woody stems, a relatively open canopy and grassy ground cover, and lacked large trees, coarse woody debris and most special life forms. Restoration plantings and old regrowth were more complex, with a high density of woody stems, a relatively closed canopy and shrubby understorey. Old monoculture plantations in the tropics had acquired many of the structural attributes of intact forest, however this was not the case in the subtropics, where plantations were subject to more intensive management. The marked differences in structural complexity between sites suggest that the different types of reforestation practiced in eastern Australia are likely to vary considerably in their value as habitat for rainforest biota. (C) 2003 Elsevier Science B.V. All rights reserved.

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Two forms of small-scale forestry are developing in Australia, each with different impacts on rural communities. One is based on growing short-rotation Eucalyptus globulus (blue gum) for pulp and the other on production of higher-value products from longer-rotation native hard-woods. Several impediments exist to further development of small-scale forestry, including the lack of a small-scale forestry culture, concerns over harvest rights, lack of market development, the long wait for returns, and satisfaction with current land uses. Nevertheless, the rapid increase in farm woodlot establishment in the past five years has paralleled the strong increase in the private industrial plantation estate. As markets develop and hindrances are overcome, landholders not previously interested in small-scale forestry may consider ita worthwhile land use.

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Two experiments were conducted to examine whether the conclusions drawn regarding the timing of anticipatory information pick-up from temporal occlusion studies are influenced by whether (a) the viewing period is of variable or fixed duration and (b) the task is a laboratory-based one with simple responses or a natural one requiring a coupled, interceptive movement response. Skilled and novice tennis players either made pencil-and-paper predictions of service direction (Experiment 1) or attempted to hit return strokes (Experiment 2) to tennis serves while their vision was temporally occluded in either a traditional progressive mode (where more information was revealed in each subsequent occlusion condition) or a moving window mode (where the visual display was only available for a fixed duration with this window shifted to different phases of the service action). Conclusions regarding the timing of information pick-up were generally consistent across display mode and across task setting lending support to the veracity and generalisability of findings regarding perceptual expertise in existing laboratory-based progressive temporal occlusion studies.