[Relationship between the prophase growth of knots and the radial growth of trunk in Pinus koraiensis].

Abstract

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.