山地杉木人工林择伐环境效益价值动态变化

以33a生杉木(Cunninghamia lanceolata(Lamb.)Hook.)人工纯林为研究对象,研究择伐强度对森林环境效益的影响.设置弱度(12.5%)、中度(22.9%)、强度(49.3%)和极强度(62.7%)4种不同择伐强度,跟踪调查试验样地5a和8a后土壤及凋落物持水、保肥及林分固碳释氧的价值变化,分析不同择伐强度对生态环境效益的影响.结果表明:随着择伐强度的增大,生态环境效益总价值呈先增大后减小的变化趋势;弱度和中度择伐5a和8 a后,可产生环境收益463.5~804.2元/hm2;强度择伐5 a后,导致环境成本23.7元/hm2,但8 a后可产生环境收益747.4元/hm2;极强度择伐5 a和8 a后,导致环境成本488.6和48.1元/hm2.因此,杉木人工林弱度、中度和强度择伐,能较好地促进其发挥涵养水源、保肥和固碳释氧3方面的生态服务功能,建议类似林分择伐强度不超过强度择伐.

Dynamic Change of Value of Forest Environmental Benefit with Selective Cutting of Chinese Fir Plantation in the Mountain

The effect of selective cutting intensity on forest environmental benefits was conducted in 33-year-old pure Chinese fir plantations. Plots of different selective cutting intensities,including low intensity (12. 5%), moderate intensity (22. 9%),high intensity (49. 3%)and extra-high intensity (62. 7%)were set up. The ecological value change of water and fertilizer conservation of the soil and litter,and carbon fixation and oxygen release of the stand were surveyed. Basing on them,the impact of selective cutting intensity on forest environmental benefits 5 and 8 years later was analyzed. The results showed that the value of forest environmental benefit increased at first,then decreased with the selective cutting intensity increasing. It could produce the environmental income (463. 5~804. 2 Yuan/hm2 )under selective cutting of low and medium intensity 5 and 8 years later. Selective cutting of high intensity led to the environmental cost (23. 7 Yuan/hm2 )5 years later,but it could produce the environmental income (747. 4 Yuan/hm2 )8 years later. Selective cutting of extra-high intensity led to the environmental cost 5 and 8 years later,respectively 488. 6 Yuan/hm2 and 48. 1 Yuan/hm2 . So, selective cutting of low,moderate and high intensity can effectively promote ecological service function of Chinese fir plantation,including water and fertilizer conservation,carbon fixation,and oxygen release. It is recommended that selective cutting is not more than high intensity for the similar stand.