论文部分内容阅读
二白杨人工林的部分测树因子以正态分布拟合的偏度与峭度呈现如下规律:(1)偏度依胸高直径、树高、林龄的增加而变小,10年后接近正态;却随形率(q_2)的增加而增大,而依胸高直径(树高、年龄)的增大相应的变小,在幼林期为右偏,约在10年后近于正态.(2)峭度亦随胸径(树高、年龄)形率(q_2)的增大逐渐减小,峰值的变化,除形率(q_2)由负到正外其它测树因子均为由正到负最后趋于稳定,(3)经测定t_1,t_2的绝对值均小于1.96,故说明了其分布均遵从标准正态分布.
The results show that the skewness and kurtosis of partial tree measures of Populus simonii plantation fitting with normal distribution show the following rules: (1) The skewness decreases with the increase of thoracic diameter, tree height and age, and nearly 10 years later But increased with the increase of the rate (q_2), but decreased correspondingly with the increase of the diameter of thoracic cavity (tree height and age), and shifted to the right side in young forest and nearly normal in about 10 years. (2) The kurtosis also decreased gradually with the increase of DBH (tree height and age) (q_2), and the change of peak value. The other tree factors (q_2) from negative to positive were positive (3) The absolute values of t_1 and t_2 are all less than 1.96, so it shows that their distributions follow the standard normal distribution.