樟子松节子的大小及分布

以不同树龄、不同密度的樟子松(Pinus sylvestris var.mogolica)人工林为研究对象,基于6块标准地中30株样木树干解析和节子剖析数据,揭示节子的垂直分布和水平分布规律,分析不同林分条件下节子分布规律的变化。结果表明:节子直径的垂直分布趋势是从伐根到大约树高的45%处逐渐增加,然后向上逐渐减小,但减小趋势趋于平缓;节子的水平分布服从均匀分布;不同林分条件下,樟子松节子的垂直分布状况不相同,随着林分密度的增大,节子直径的最大值逐渐减小,而且最大节子在树干上的位置也逐渐升高;随着林分树龄的增大,节子直径的最大值也逐渐增大,但是最大值出现的位置不变。节子直径最大值可以通过林分密度、胸径和枝下高建立的模型来描述;节子的频数分布呈现正态分布的趋势。

Knot Size and Distribution of Mongolian Pine Plantations

The vertical and horizontal distribution of knots were revealed to analyse the distribution rule of knot under different stand conditions base on the data of stem analysis and knot characteristics from 30 sample trees in 6 sample plots for Mongolian pine plantations with different ages and stand densities.Results show that the vertical distribution of knots first gradually increases from stem base to the position about 45 percent of total tree height,and then gradually decreases,but the decreasing tendency goes to smooth.The knots obey uniform distribution in horizontal direction,and the vertical distributions of knots are different under different stand conditions.The maximum value of knot diameter(Dmax) decreases with the increase of stand density,and the location of maximum knot is higher in denser stand.Dmax increases with increasing stand age,while its location is unchanged in the stands of different ages.Dmax can be described by stand density,diameter at breast height and the lowest height of living branch,and the frequency of knot obeys normal distribution.