青海大通退耕还林地林分水分生产力研究

 为了解青海东部黄土高原寒区退耕还林地人工林的水分生产力水平,2001—2003年对青海省大通县退耕还林的人工林进行了群落蒸散测算、标准地生物量调查和解析木分析,并研究了青杨灌木混交林、白桦紫果云杉混交林、华北落叶松纯林、紫果云杉纯林、白桦纯林等11种林分类型退耕还林人工林的林木水分生产力。结果表明:1)3 000株/hm2左右密度的林分是该区较为适宜的造林密度标准;2)在目前的技术经济水平条件下,2 1003333株/hm2密度的青杨灌木混交林成林、白桦纯林、紫果云杉纯林和白桦紫果云杉混交林水分生产效率居所有林分之首,其水分生产力指标可作为该地区常规造林技术条件下乔木成林的水分生产力标准;3)3000株/hm2左右密度的青杨灌木混交林、白桦紫果云杉混交林、紫果云杉纯林和白桦纯林成林的水分生产潜力基本达到了目前当地林木的最大生产能力。表明上述林分类型的造林模式可作为今后退耕还林工程和林业生态工程建设的发展方向。

Water productivity of plantations in removal land from cultivation to afforestation in Datong of Qinghai

In order to find out the water productivity of some artifical plantations in removal land from cultivation for afforestation in the cold region of Loess Plateau of east Qinghai,commuinty evapotranspiration,sample area biomass and moisture potential productivity were investigated and analyzed in Datong county in Qinghai province from 2001 to 2003,and water productivity of 11 types of artificial plantions in the removal land were studied and.The results show that,3000 trees per hm² is a proper standard of plantions density for this region;Under current technological and economic condition,the productive efficiency of green poplar and shrub mixed forest,Asia white birch pure forest,China spruce pure forest,and Asia white birch and China spruce mixed forest with the density of 2103333 trees per hm²,which is the top of all,can serve as potential productivity standard of actual productivity of mature arbor forest;The potential productivity of green poplar and shrub mixed forest,Asia white birch and China spruce mixed forest,China spruce pure forest and Asia white birch pure forest with the density of 3 000 trees per hm² have attained or been closed to local maximum tree productivity at present.These types of forestation models are the developing orientation of the removal land from cultivation for afforestation project and forestry ecological project.