Abstract
Within-tree variation (at the positions of 0.2, 2.2, 4.2, and 6.2m above the ground) of wood properties was investigated in the 59-year-old kuromatsu (Pinus thunbergii) No.26F1 family, an open-pollinated family of kuromatsu No.26 selected by growth characteristics in the tree breeding program. Trees of akamatsu (P.densiflora) of the same age were used for comparing wood properties. No significant differences in basic density (BD) and latewood tracheid length (TL) at 4 different heights, except for BD at 6.2m, were recognized between kuromatsu No.26F1 and akamatsu. In addition, significant differences between kuromatsu No.26F1 and akamatsu were not found in microfibril angle of the S2 layer in latewood tracheids (MFA), modulus of elasticity and modulus of rupture in static bending, and compressive strength parallel to grain at 2.2m height. On the other hand, the boundary between juvenile wood (JW) and mature wood (MW), which was determined by TL and MFA, was within the 15th to the 20th annual ring from the pith in both kuromatsu No.26F1 and akamatsu. In addition, significant differences in mean values of wood properties in JW and MW were not found between kuromatsu No. 26F1 and akamatsu, except for BD of MW at 6.2m
