黄龙山林区封育油松种群动态研究

Dynamic characteristics of hillsides-closed afforested Pinus tabulaeformis population in Huanglongshan forest zone

对不同封育年限油松种群的高度、径级、年龄结构进行分析,运用马尔可夫转移矩阵预测种群密度动态.结果表明,不同封育年限种群的生长发育明显不同.种群个体高度以2～4 m和6～8 m占优势,胸径以0～2 cm的小径阶和＞20 cm的大径阶占较大比重;在各封育系列中,种群的密度中、大级出现几率较大.在封育45年前,种群的年龄结构中大树所占比例最大;45年后,小树和幼苗则较多,但种群弱小个体大量死亡.本区天然林保护年限最短应确定为45年.

This paper analyzed the height, diameter of breast height （DBH）, and age structure of hillsides-closed afforested Pinus tabulaeformis population, with its density characteristics forecasted by Markov matrixes. The results indicated that the population growth at different hillsides-closed afforested stages presented visible difference. The dominant height ranges and DBH classes of P. tabulaeformis individuals were 2-4 m and 6-8 m, and 0 -2 cm and 〉20 cm, respectively, and the population with medium and larger DBH classes had a larger density probability than that with smaller DBH class. There was a larger proportion of old trees if the hillsidesclosed afforestation was less than 45 years, while young trees and seedlings were more but died with high proportion if the afforestation was more than 45 years. It could be concluded that natural forest in this area should be protected for at least 45 years.