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在定量计算天然次生林经5种不同强度采伐(弱度18.6%、中度28.2%、强度45.5%、极强度75.5%、皆伐100%)10 a后的经济效益指标,定位测定伐后10 a林地土壤肥力和蓄水保土指标变化量的基础上,采用集对分析方法,定量计算天然次生林不同强度伐后10 a的综合效益,从而确定最优采伐强度。结果表明,仅考虑经济效益,皆伐最优,极强度择伐次之,弱度择伐最差,其评价值依次为0.566、0.553和0.430;仅考虑生态效益,弱度择伐最优,中度择伐次之,皆伐最差,其评价值依次为0.754、0.651和0.472;综合考虑经济和生态效益,中度择伐最优,其余从大到小依次为弱度择伐、强度择伐、极强度择伐和皆伐,其评价值依次为0.601、0.589、0.535、0.509和0.508。研究表明,“中度择伐”是闽北天然次生林伐区作业的最优采伐强度,适合类似本试验自然条件的林区借鉴。
The economic benefit index of natural secondary forest after 5 years of different harvesting (18.6% for weakness, 28.2% for moderate, 45.5% for moderate intensity, 75.5% for extreme intensity and 100% for clear-cutting) Based on the changes of forest soil fertility and soil and water conservation indexes, the set-pair analysis method was used to quantitatively calculate the comprehensive benefit of 10-year after different intensity of natural secondary forests to determine the optimal harvesting intensity. The results showed that, considering economic benefits only, the clear-cutting was the best, the second was the strongest cutting and the second was the weak cutting. The evaluation values were 0.566, 0.553 and 0.430, respectively; only considering ecological benefits, , Followed by moderate cutting, and the clear cutting was the worst. The evaluation values were 0.754, 0.651 and 0.472, respectively. Considering the economic and ecological benefits, moderate selective cutting was the best and the others were weak selective cutting, Selective cutting, intensive cutting and clear cutting are the most important indexes, which are 0.601, 0.589, 0.535, 0.509 and 0.508 respectively. The results show that “moderate selective cutting” is the optimal harvesting intensity of natural secondary forest cutting in northern Fujian, which is suitable for forest areas similar to the natural conditions of this experiment.