Fig. 7

Preparation of small clear specimens and calculation method of mean values at five radial positions (1st–5th, 6th–10th, 11th–15th, 16th–20th, and 21st–36th annual ring from the pith) (Tanabe et al. 2014). Note: a and c, cross-sectional images of radial board in sample trees A and B, respectively; b and d, cross-sectional images of small clear specimen in sample trees A and B, respectively. Due to sample tree size, specimen could not be obtained from all radial positions (in this Fig., specimens were not obtained from the 16th–20th annual ring positions in sample tree A and the 21st–36th annual ring positions in sample tree B). Numbers in parentheses show examples of AD value (g cm⁻³). For example, the mean value of a family in the 1st–5th positions (0.46 g cm⁻³) was calculated by averaging the values obtained from the same positions of sample tree A (0.45 g cm⁻³), sample tree B (0.47 g cm⁻³), and other sample trees