中国东北地区有3700多万hm2森林资源,大部分为已严重退化的天然次生林。如何经营这些森林,是不予管理、任其退化,直至形成杂灌丛;还是"砍次留好",促进更新,逐步引向永久性森林?哈尔滨市林业局在山河、转山和丹青河3个直属林场...中国东北地区有3700多万hm2森林资源,大部分为已严重退化的天然次生林。如何经营这些森林,是不予管理、任其退化,直至形成杂灌丛;还是"砍次留好",促进更新,逐步引向永久性森林?哈尔滨市林业局在山河、转山和丹青河3个直属林场,开展了以均衡发挥生态效益和经济效益为目地的经营实践,仅10余年时间3个林场就已获得了低投入、高产出的良好效果,走上了资源与经济良性循环的轨道。2009年9月,哈市林业局在中国林科院专家支持下,邀请德国森林经营专家Heinrich Spiecker教授和法国农业部高级顾问Dominique Danguy des Deserts先生考察了经营现场,并深入探讨了这些科学实验及其理论价值。展开更多
We investigated the effect of forest thinning on soil nitrogen mineralization, nitrification and transformation in a Cryptomeria japoni-ca plantation at high elevation to provide basic data for forest manage-ment. We ...We investigated the effect of forest thinning on soil nitrogen mineralization, nitrification and transformation in a Cryptomeria japoni-ca plantation at high elevation to provide basic data for forest manage-ment. We chose four study plots for control, light, medium and heavy thinning treatment, and three sub-plots for buried bag studies at similar elevations in each treatment plot to measure the net N mineralization and nitrification rates in situ. The contents of soil inorganic N （ammonium and nitrate） were similar between treatments, but all varied with season, reaching maxima in September 2003 and 2004. The seasonal maximum net Nmin rates after four treatments were 0.182, 0.246, 0.303 and 0.560 mg？kg-1？d-1 in 2003, and 0.242,0.258,0.411 and 0.671 mg？kg-1？d-1in 2004, respectively. These estimates are approximate with the lower annual rates of N mineralization for this region. Forest thinning can enhance net N mineralization and microbial biomass carbon. The percentage of annual rates of Nmin for different levels of forest thinning compared with the control plot were 13.4%, 59.8%and 154.2%in 2003, and 0.1%, 58.8%and 157.7%in 2004 for light, medium, and heavy thinning, respectively. These differences were related to soil moisture, temperature, precipita-tion, and soil and vegetation types. Well-planned multi-site comparisons, both located within Taiwan and the East-Asia region, could greatly im-prove our knowledge of regional patterns in nitrogen cycling.展开更多
文摘中国东北地区有3700多万hm2森林资源,大部分为已严重退化的天然次生林。如何经营这些森林,是不予管理、任其退化,直至形成杂灌丛;还是"砍次留好",促进更新,逐步引向永久性森林?哈尔滨市林业局在山河、转山和丹青河3个直属林场,开展了以均衡发挥生态效益和经济效益为目地的经营实践,仅10余年时间3个林场就已获得了低投入、高产出的良好效果,走上了资源与经济良性循环的轨道。2009年9月,哈市林业局在中国林科院专家支持下,邀请德国森林经营专家Heinrich Spiecker教授和法国农业部高级顾问Dominique Danguy des Deserts先生考察了经营现场,并深入探讨了这些科学实验及其理论价值。
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05070303)
文摘We investigated the effect of forest thinning on soil nitrogen mineralization, nitrification and transformation in a Cryptomeria japoni-ca plantation at high elevation to provide basic data for forest manage-ment. We chose four study plots for control, light, medium and heavy thinning treatment, and three sub-plots for buried bag studies at similar elevations in each treatment plot to measure the net N mineralization and nitrification rates in situ. The contents of soil inorganic N （ammonium and nitrate） were similar between treatments, but all varied with season, reaching maxima in September 2003 and 2004. The seasonal maximum net Nmin rates after four treatments were 0.182, 0.246, 0.303 and 0.560 mg？kg-1？d-1 in 2003, and 0.242,0.258,0.411 and 0.671 mg？kg-1？d-1in 2004, respectively. These estimates are approximate with the lower annual rates of N mineralization for this region. Forest thinning can enhance net N mineralization and microbial biomass carbon. The percentage of annual rates of Nmin for different levels of forest thinning compared with the control plot were 13.4%, 59.8%and 154.2%in 2003, and 0.1%, 58.8%and 157.7%in 2004 for light, medium, and heavy thinning, respectively. These differences were related to soil moisture, temperature, precipita-tion, and soil and vegetation types. Well-planned multi-site comparisons, both located within Taiwan and the East-Asia region, could greatly im-prove our knowledge of regional patterns in nitrogen cycling.
