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以金沟岭林场云冷杉针阔混交林为研究对象,分析了该林场1987—2005年间41块固定样地的调查数据,计算了相邻径级的立木株数比q值,分析了其直径结构变化。研究表明:1)林分小径阶q值逐年下降。18年来,I-1和I-3小区的q值分别从1.39和1.52下降到1.14和1.06,表明小径阶林木的直径结构已趋于不合理。2)6 cm径阶以下的幼树更新较差。3)林分q值的均值不能真实地表达林分的直径结构,而按小径木、中径木和大径木来分别计算林分的q值,能够较真实地表达林分直径结构。
Taking the mixed forest of spruce-fir and broad-leaved forest in Jingouling Forest Farm as the research object, the survey data of 41 fixed plots from 1987 to 2005 in this forest farm were analyzed. The numerical value q of stand number of the adjacent diameter class was calculated, and its diameter structure Variety. The research shows that: 1) The diameter of step size q declines year by year. For 18 years, the q values of I-1 and I-3 plots decreased from 1.39 and 1.52 to 1.14 and 1.06, respectively, indicating that the diameter structure of small-diameter timber trees tended to be unreasonable. 2) Saplings younger than 6 cm are less well updated. 3) The mean q value of stand can not truly express the diameter structure of stand, but the q value of stands can be calculated according to diameter timber, diameter timber and diameter timber, which can represent the diameter structure of stand more faithfully.