【摘要】 用野外生态试验的方法研究水曲柳(Fraxinus mandshurica Rupr.) 种群发生与环境条件的生态关系。通过定量分析,确定影响水曲柳种群天然发生的主要环境因子为林分郁闭度、林地表层土壤水分和林下地被物。林分郁闭度影响种群的发生进程、幼龄个体的生长发育及其与草本植物的种间竞争,水曲柳宜在郁闭度为0.4—0.8的林分内天然发生;表层土壤水分通过影响种子后熟和萌发限制种群的发生数量;林下地被物的存在阻隔了种子与地表的接触,从而影响种群的天然发生数量,清除这些地被物可促进种群的天然发生。更多还原

【Abstract】 This paper deals with the effect of forest environmental factors on the occurrence of manchurian ash (Fraxinus mandshurica Rupr.) population via field ecological experiments. It was found that under the natural condition, the principal factors affecting the occurrence of the population are soil moisture content, closure of the stand and the situations of the ground layer. The soil moisture content is the key of them. The soil moisture content affects both the ash germination and after-ripening process of the secd when the seeds are sowed on litter. But if the seeds are sowed under litter, the soil moisture content only affects the after-ripening process. By reducing closure of the stand, the occurrence of this population can be promotcd and the disadvantageous effect due to the lack of soil water can be reduced. But if the closure of the stand is very low, the young individuals of the population can not develop well due to competitive pressure from weeds.更多还原