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以越南东南部胖大海天然更新林为研究对象,运用6个聚集度指标分析不同林分优势度和郁闭度等级下胖大海幼树幼苗更新3个阶段的空间分布格局特征,并运用Iwao回归方程和Taylor幂法则模型进行检验,比较胖大海的出现相对频率(Ey)在不同林分优势度和郁闭度等级下的差异性。结果表明:胖大海幼树幼苗的空间分布型呈聚集分布型;不同林分优势度和郁闭度等级对胖大海幼树幼苗更新的影响在第2、第3阶段的Ey存在显著性差异,而在第1阶段差异性不显著;胖大海在优势度低级的Ey,在第1阶段分别是优势度中级和高级的1.05和1.17倍,在第2阶段为优势度高级的30%,在第3阶段分别为优势度中级和高级的99%和31%;胖大海在郁闭度1级的Ey,在第1阶段分别是郁闭度2、3和4级的85%、1.32倍和75%,在第2阶段分别是郁闭度2、3和4级的1.80、1.97倍和69%,在第3阶段依次为郁闭度2、3和4级的1.29、1.10倍和43%。胖大海幼树幼苗基本适应高郁闭度林分,对光照强度要求较低。
Taking the natural renewal forest of Pandahai in the southeastern part of Vietnam as the research object, the spatial distribution pattern of three stages of sapling seedling growth in different stands and degrees of canopy density was analyzed by using six indicators of degree of aggregation. The Iwao regression Equation and Taylor power law model were tested to compare the relative frequency (Ey) of the fat sea in different stand dominance and canopy density. The results showed that the spatial distribution patterns of young saplings were aggregated and distributed. The effects of different stand dominance and canopy density on the regeneration of young saplings were significantly different in the second and third stages of Ey, While the difference is not significant in the first stage; Pyo in the lower dominance of Ey, respectively, in the first stage were 1.05 and 1.17 times the dominance of intermediate and advanced, in the second stage dominance of advanced 30% in the first 3 stages were 99% and 31% of the intermediate and advanced dominance, respectively. The Ey of the oceans at the closed canopy level 1 was 85%, 1.32 and 75% of the canopy degrees 2, 3 and 4 in the first stage, respectively %, 1.80, 1.97 and 69% of canopy degrees 2, 3 and 4 in stage 2, and 1.29, 1.10 and 43% of canopy degrees 2, 3 and 4 in stage 3, respectively. Fat blue sea saplings seedlings basically adapt to tall canopy density of forest, the light intensity requirements are low.