关帝山天然次生针叶林的林隙特征

通过对山西省关帝山天然次生针叶株中63个林隙的调查，研究了林隙的基本特征。结果表明，关帝山天然次生针叶林林冠空隙的大小变化范围为5．78～234．48m^2，平均为60．07m^2；扩展林隙的大小变化范围为18．49-349．68m^2，平均为114．92m^2。大多数林隙是由1～4株形成木创造的。径级为20～40cm，高度在20～30m的主林层树木形成林隙的可能性最大。林隙形成时间以5-20a这段时间为主。不同森林类型的林隙大小存在较大的差异，云杉Picea spp．林以小林隙为主，而油松Pinus tabulaeformis林则分布着不同面积的林隙。林隙形成的原因主要是人为砍伐、折干、掘根风倒和枯立等、表7参19

Gap characteristics in a secondary coniferous forest of Guandi Mountain,Shanxi Province

The researches on gap in temperate zone coniferous forests within mountainous region are little. Through a field survey of 63 gaps in a secondary coniferous natural forest, namely Pinus tabulaeformis forests （19 gaps）, Larix principis-rupprechtii forests （26 gaps）, and Picea wilsonii or Picea meyeri forests （18 gaps）, within the Pangquangou Nature Reserve of Guandi Mountain, Shanxi Province, gap characteristics were analyzed. The canopy gaps （CG） varied from 5.78 to 234. 48 m^2 and averaged about 60. 07 m^2. The expanded gaps （EG） varied from 18. 49 to 349.68 m^2 and averaged about 114. 92 m^2. Gaps were caused from one or more of these sources： logging, breakage at the trunk, uprooting from blow-down, and standing dead. Most of the gaps were made by 1 -4 trees （gap maker）. The probability of gap development was greatest when trees forming the canopy were 20 -40 cm DBH and 20 -30 m tall with most gaps being formed within the last 5 -20 years. Also, gap sizes differed greatly in different forest types. Most gap areas in Picea spp. forests were small, but gap areas distributed in Pinus tabulaeformis forests are various. [ Ch, 7 tab. 19 ref.]