School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemImproved logging and portable sawmilling practices in Papua New Guinea( 2004)The management of the natural forest in Papua New Guinea has been a concern locally, nationally and internationally due to poor logging practices in the past three decades. The method of logging adopted is selective logging using conventional logging systems. Forestry as a renewable resource is a source of food, materials, fuel wood, and income for local people and is the third largest revenue source for the country. Therefore better logging practices using reduced impact logging system may be a better way to manage the natural forest sustainably with reduced cost and damage to the environment. This study investigates whether: • Reduced impact logging is better or worse than conventional logging; and • Reduced impact felling and processing is better or worse than conventional felling and processing in portable sawmilling. The data for the research comes from two different natural forest harvesting studies. Firstly, logging operations were studied using two sets of data. The first set was from a 100-hectare plot and the second from four one-hectare plots were qualitatively and quantitatively analyzed. The second source of data was from the portable sawmills that were basically owned by local resource owners. Comparisons were made on conventional and reduced impact techniques applied to both the logging and the portable sawmill operations. The variables tested were merchantable trees harvested, harvesting waste, skid tracks, damages to residual trees, damages to potential crop trees, tree species lost, forest canopy gap size, regeneration, sawn timber recovery rate and harvesting cost. Results reveal significant differences between conventional and reduced impact techniques applied in logging operations and also in portable sawmill operations. In the 100 hectare logging operations, reduced impact logging has reduced the number of trees harvested from 19 to 11 trees per ha, wood waste from 6.4 to 1.7 cubic metres per ha, distance of skid tracks from 296 to 172 metres per ha, width of skid track from 5.4 to 4.3 metres, residual trees damaged from 43 to 21 percent, number of potential trees damaged from 29 to 11 trees per ha, the sizes of canopy gap from 50.1 to 17.9 percent, number of species lost from 10 to 3 species per ha and harvesting cost from K651 to K517 per ha. In addition, similar results were found in the four one-hectare plots. However, diameter increment of residuals and regeneration after logging was greater in conventional logging than reduced impact logging. In the portable sawmill operations reduced impact felling and processing reduced harvesting (wood) waste from 28 to 2 cubic metres per ha, residual trees damaged from 33 to 15 percent, number of potential crop trees damaged from 7 to 4 trees per ha, canopy gap size from 30 percent to 10 percent and number of species lost from 12 to 2 species per hectare. In addition, reduced impact logging improved sawn timber recovery rate from 27 to 47 percent. Harvesting cost in reduced impact felling and processing was increased by K21 per hectare, however, statistical test shows no significant difference between conventional and reduced impact felling and processing systems. The thesis concludes that: • Reduced impact logging system is better than conventional logging system; and • Reduced impact felling and processing is better than conventional felling and processing in portable sawmilling.