东灵山辽东栎林优势林木种群直径结构的研究

从山体下部到上部调查了北京东灵山辽东栎林一个长 3 6 4m的样带 ,对优势林木种群的直径结构 ,按山体的上部、中部、下部三个不同部位进行统计。选定乔木层优势种群辽东栎、大叶白蜡、五角枫、棘皮桦和灌木层优势种群二色胡枝子、六道木、照山白、柔毛绣线菊为研究对象 ,结合生物学特性分析了 8种乔灌木种群的直径结构 ,及其沿环境梯度的动态趋势。在乔木层 ,棘皮桦在山体中部和下部的亚种群幼苗幼树株数少 ,个体生长不良 ,密度极低种群呈衰退趋势。其余3个物种种群的幼苗幼树数量多 ,种群密度较高。辽东栎种群从山体下部到上部的直径结构合理呈稳定状态。大叶白蜡和五角枫种群随海拔升高在数量、密度等方面呈现相互替代的现象。在灌木层 ,除过照山白种群 ,二色胡枝子、六道木和柔毛绣线菊 3个种群的幼苗株数丰富 ,直径结构合理。从整体上看 ,如果对辽东栎林群落不加人为的干扰和破坏 ,辽东栎林群落将进一步向成熟林方向发展。

STUDY ON POPULATION DIAMETER STRUCTURES OF TREE AND SHRUB DOMINANT PLANTS IN QUERCUS LIAOTUNGENSIS FOREST IN DONGLING MOUNTAIN IN BEIJING

The typical Quercus liaotungensis forest communities along 364m long sample belt along the slope of Dongling Mountain in Beijing have been divided to be the lower, middle and higher 3 parts. The 8 dominant plant population diameter (or base diameter) structures and dynamics of Quercus liaotungensis, Fraxinus rhynchopylla, Betula dahurica, Acer mono, Lespedeza biocolor, Abelia biflora,Rhododendron micranthum,Spiraea pubescens populations in the community have been studied systemically on statistics along environment grade. Except for the Betula dahurica population that are declining, the other populations all show developing or stable status which have more numbers of younger seedling. Quercus liaotungensis populations show stronger adapted ability as altitudes increase since diameter structures are reasonable. The Fraxinus rhynchopylla, Acer mono populations can replace each other on the size and density along slope. In shrub layer, except Rhododendron micranthum population, Lespedeza biocolor, Abelia biflora and Spiraea pubescens have more numbers of seedlings, and their diameters structures are reasonable. In this area, if the disturbance from human being could be stopped, the Q. liaotungensis forest system will develop to be more mature status.