洮河上游高山草甸草原向草甸草原过渡带森林林型特征与经营措施

洮河上游高山草甸草原向草甸草原过渡带森林,地处青藏高原东北边缘,以珍贵的云冷杉暗针叶林为顶级群落,这里的森林对青藏高原东北边缘藏区的生态平衡具有十分重要的作用。通过对这片森林林型特征的调查,提出了各林型的经营措施,以保护该区的生物多样性,使之永续利用。

吉林省发生重特大森林火灾林型的特征

根据吉林省1969—2010年间的森林火灾资料数据统计分析,容易发生重特大森林火灾的林型主要是柞树林、阔叶混交林和针阔混交林。阔叶混交林的特征是柞树占4成以上、混有白桦或混有杨树和白桦,并且该林型疏密度为0.5～0.7,或者林龄在11～30 a之间;针阔混交林的特征是含有柞树或含有红松和柞树,并且疏密度为0.7～0.8,或者林龄在1～40 a之间;柞树林的特征是疏密度为0.5～0.7,或者林龄在1～40 a之间。

贺兰山针叶林结构与多样性的海拔格局

贺兰山是针叶林分布的交错区,为我国油松林分布的西界和青海云杉林分布的东界。通过沿海拔梯度设计样带,系统布设样方,对贺兰山针叶林进行了野外调查。结果表明,贺兰山针叶林的平均树高和总胸高截面积随海拔升高而增加,同时立木组成中胸径大的树木增多,表明其生长状况逐渐变好。随着海拔升高,群落的物种丰富度不断降低,但种类组成的变化是连续的。林下土壤的土层深度、有机质和全氮质量分数随海拔升高而增加,土壤pH值则随着海拔升高而降低。土壤因子随海拔的变化,是研究区针叶林变化的生态梯度,反映了气候因子的作用。

Soil Physical and Chemical Properties of Five Subtropical Forests in Lingao of Hainan

With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that： the soil total porosity was the highest in the Casuarina equisetifolia forest （46.168%）, but the lowest in the Encalyptus robusta forest （39.46%）. The soil capillary porosity was the highest in the Acacia mangium forest （22.57%）, but the lowest in the secondary forest （18.95%）. The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic （pH 4.5-5.5）, and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents （with a mean value of 2.29 mg/kg） and ammonium N contents （with a mean value of 3.93 mg/kg）. For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.

LOCAL CHARACTERISTIC OF HOLOMORPHIC AUTOMORPHISM ON CLASSICAL DOMAIMS

A local characteristic of the holomorphic automorphism on the four kinds of the classic domains is obtained.