Radial variation in the size of axial elements in relation to stem increment in Quercus serrata

Abstract

In Quercus serrata, radial variations of wood fibre length, earlywood vessel element length, and earlywood vessel lumen diameter were investigated and maturation ages of them were estimated using nonlinear segmented regression analysis as proposed by Peszlen (1994). In addition, the age at the maximum point of current annual increment and mean annual increment were estimated by using the Gompertz growth function fitted to the variation of cumulative ring width with ring number from the pith. In the same radial strip, the maturation ages both of wood fibre length and the earlywood vessel element length were similar, and those were close to the ages at the maximum point of current annual increment, whereas the maturation age of earlywood vessel lumen diameter was generally greater, close to the age at the maximum point of mean annual increment. These results indicate that earlywood vessel lumen diameter is the best indicator of the three anatomical properties tested and that a relationship exists between the maturation ages of the size of axial elements and radial stem increment.