We analyzed the differences in knot property of linear and curved knots of dominant, medium, and inferior wood with thirty-three Pinus koraiensis trees from Mengjiagang Forest Farm and Linkou Forestry Bureau in Heilongjiang Province. We divided the 33 trees into two groups according to the height of the site index. We constructed a trunk diameter growth models to explore the connection, between the knot growth inflection points and the successive growth of diameter, and to screen for the types that had a weaker impact on wood quality. The results showed that there were significant differences in knot diameter, sound knot length, proportion of loose knot and inflection point age between the two knot types. The growth inflection point of curved knot was between 8 and 12 years old, while that of linear knot was between 7 and 10 years old. The knot of curved knots in different grades of wood were larger than linear knot in terms of knot diameter and sound knot length. The decrease in the proportion of sparse knots indicated that the healing time of knot became shorter. The growth of linear knots remained essentially uniform with radial growth. The age of the growth inflection point of curved knots was later than the age at which the maximum of successive annual growth in diameter was produced. The age of trunk diameter inflection and the age of knot growth inflection were later for better site conditions. The age of trunk diameter inflection and the age of knot growth inflection were later for dominant woods than for average nodule growth. Different site conditions and trunk diameters affected nodule growth, and nodule attributes differed between the two nodule types as trunk diameter grew. Delaying the maximum continuous annual growth by rationally formulating forest management measures can lengthen the duration of trunk growth while extending branch growth, increase the proportion of curved knot to optimize wood quality, and improve wood quality.
以黑龙江省林口林业局和孟家岗林场选取的33株红松为研究对象,根据立地指数的高低分为两组,对优势木、平均木和劣势木直线型节子和曲线型节子的节子属性进行差异性分析,并构建树干直径生长模型,探究节子生长拐点和直径连年生长的联系,筛选对木材质量影响较弱的节子类型。结果表明: 两种节子类型间节子直径、健全节长度、疏松节比例和节子生长拐点年龄都有显著差异。曲线型节子的生长拐点主要分布在8～12年,直线型节子的生长拐点主要分布在7～10年;不同等级木曲线型节子的节子直径和健全节均大于直线型节子,而疏松节比例小于直线型节子,疏松节比例的减少说明节子愈合时间变短。随着树木的径向生长,直线型节子的生长保持基本一致,曲线型节子的生长拐点年龄晚于直径连年生长量最大值产生的年龄。立地条件较好的树干直径拐点年龄和节子生长拐点年龄更晚,优势木的树干直径拐点年龄和节子生长拐点年龄晚于平均木和劣势木。不同的立地条件和树干直径均影响节子的生长,而随着树干直径的生长,两种节子类型间的节子属性会产生差异。通过合理制定林木经营措施,延迟连年生长量最大值的年龄,可以在拉长树干径向生长时间的同时延长枝条的生长,增加曲线型节子的比例以优化木材质量,提高木材品质。.
Keywords: knot diameter; knot growth inflection point age; loose knot length; sound knot length; trunk diameter growth model.