福建将乐林场栲属次生林直径结构的研究

Study on diameter structure of Castanopsis secondary forest in Jiangle Forest Farm,Fujian

选用福建将乐林场的十块栲属次生林的样地调查数据分析该地区栲属次生林的直径结构,为将乐林场栲类次生林的经营和结构调整提供依据。采用样地调查法获得12块样地的基本数据,将胸径分大、中、小三径级计算各径级比例及q值,用4种概率分布对各样地直径结构进行拟合,检验不同的拟合效果。小径级林木所占比例较大,占到了56.9%～88.1%,中径级和大径级的q值变化较大,Weibull分布拟合效果最好,γ分布次之,正态分布和对数正态分布拟合效果较差。该区栲属次生林的直径分布基本符合异龄林直径分布的特点,可以以q值为参考对大、中级林木进行进一步结构调整研究。

By selecting 10 plots of Castanopsis secondary forest as the studying object in Jiangle Forest Farm in Fujian province,the sample-plot survey were made and the diameter structure and diameter classes were investigated for providing the basis to adjust the stand structure and to manage the forest plots.Through adopting Plot survey method,the 12 basic data were obtained,the diameters were divided into large,medium and small classes to calculate the proportions of each class and q-value.The diameter structures of the plots were fitted with 4 kinds of probability distribution type to test the fitting effects of different methods.The results show that the small classes trees occupied greater proportion,about 56.9%~88.1%.the q-values of medium and large classes changed largely;the fitting effect with Weibull distribution was the best,the next was with γ-distribution,followed by normal and lognormal distribution in ture,being poor effects.It can be concluded that the diameter distribution law of Castanopsis secondary forest in this area was basically in line with the diameter distribution characteristics of uneven-aged forest,the big and middle Castanopsis secondary forest trees can be further adjust by using q-value as a reference.