Benefit-Cost Analysis of Eucalypt Management for Sustainability in Southern China

摘要

This paper reports an economic analysis for a project investigating management of eucalypt plantations in southern China for improving sustainability and productivity. The analysis evaluated benefits and costs of the key options for more sustainable management, comparing their net benefit with that of a traditionally managed plantation as a benchmark. Estimates of physical productivity were based on benchmark studies by local scientists. As an example of crop rotation between agricultural crops and eucalypt trees, watermelons were grown for one year on a former eucalypt site, followed by a crop of eucalypts for woodchips over a 5-year rotation. As residues were ploughed back into the soil to improve soil quality, woodchip productivity increased, while the watermelons were sold as a profitable commercial crop. Annual equivalent net benefit for this approach was estimated to be considerably higher than for a standard plantation. A similar positive result was obtained with a pineapple crop rotation for two years before the eucalypts. Another option considered was retaining all litter and residues on site. It was assumed that this would allow a continuation of the first-rotation productivity for four rotations, instead of the decline of 47% observed over that period. The cost of this was the loss of sale of by-products, and costs for chopping and rolling residues. The benefit-cost ratio just for the changes was high at 2.9. These interim results suggest several options are available that retain or restore organic matter on the site, and not only improve the sustainability of plantations but also show better economic returns than that of a traditionally managed plantation. However, the distributional implications, in terms of the social groups gaining or losing, need special attention. The forest owner makes monetary gains from increased revenue, while local villagers and harvest contractors who lose access to litter and forest by-products could be worse off. Measures to compensate the low-income groups who lose would be necessary to ensure that the plantation reforms have desirable effects on welfare and social sustainability.