落叶松人工林节子内部特征变化规律研究

以落叶松人工林为研究对象,采用枝解析和节子剖析技术,获取了95株解析木和2 165个节子数据,以树木和节子自身因子为自变量建立了节子内部特征模型,包括节子直径和角度模型、节子中健全节和疏松节长度模型。模型很好地描述了节子内部特征因子的变化规律,揭示了节子内部特征因子随林木和自身变量变化的机制。结果表明:节子直径、节子角度和健全节长度都随着其所在位置高度的增加而增大,随着树木胸径的增大而增大;疏松节长度随着胸径的增大呈现增大趋势,但节子自身直径大小对其影响也较大。应用独立检验样本对所建模型进行检验,精度达到了95%以上,这些模型可以应用到林木生长模拟系统中,增加模拟效果。节子内部特征变化规律的研究也有助于揭示枝条的生长与死亡机制,对开展整枝抚育从而提高木材质量有重要意义。 

Changes of the internal characteristics of knots in larch plantation

The data of 95 sample trees and 2 165 knots in larch ( Larix spp. ) plantation were acquired using branch and knot analysis techniques. Using tree and knot factors as independent variables, we developed four models for internal characteristics of knots ( ICK) , including the knot diameter model, knot angle model, the sound knot length model and loose knot length model. The models described well the changing patterns of factors of ICK, and revealed the mechanism of ICK changes with trees and itself. The results showed that the knot diameter, angle and sound knot length increased with the increase of the height of knot position and DBH. Loose knot length increased with DBH increasing, however the knot itself also had great impact on loose knot length. The results of independent validation showed that prediction precision of each model reached over 95%, thus these models can be applied to forest growth simulation system for increasing the effect of simulation. The studies on variation patterns of ICK also help to reveal the mechanism of branch growth and death, which is of important significance to carry out pruning and therefore improve wood quality.