樟子松節子的大小及分布.docxVIP

樟子松节子的大小及分布摘 要 以不同树龄、不同密度的樟子松(Pinus sylvestris?var mongolica?)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。关键词 樟子松;人工林;节子;直径;分布Knot Size and Distribution of Mongolian Pine Plantations /Chen Dongsheng, Jin Zhongyue, Li Fengri, Jia Weiwei(School of Forestry, Northeast Forestry University, Harbin 150040, P. R. China) //Journal of Northeast Forestry University. -2007, 35(5). -19~21The 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.Key words Mongolian pine (Pinus sylvestris var mongolica); Plantations; Knots; Diameters; Distributions节子是枝条被树干包合起来的部分,它是决定木材质量的最重要的因子之一[1 -2]。木材的最佳利用率很大程度上决定于树干上的节子结构。节子常被看作是木材上的空缺或洞,甚至要比一个简单的洞影响更大,因为节子可以改变木材颗粒方向,从而影响木材的质量[3]。因此,在林分轮作时采取一定的营林措施,通过控制树干上活的或死的枝条的属性来调节木材的质量,并从营林措施的时间和强度最优