Figure 5

Distribution of the D₂O concentration ratio (C/C₀) in the xylem stem of a sugi tree estimated by using the simple one-dimensional advective diffusion transport model³⁷. (a) Constant magnitude of diffusion coefficients of D₂O [0.24 cm² day⁻¹ (= 2.8 × 10^–10 m² s⁻¹)] in all xylem stem, and (b) magnitude of diffusion coefficients changed in the intermediate wood zone (change from 0.24 cm² day⁻¹ to 0.123 cm² day⁻¹ (= 1.42 × 10^–10 m² s⁻¹) after 4.5 cm). Note: The D₂O migration velocity is 0.1 cm day⁻¹ in xylem stems. x = 0 is the top of the second tree ring removed the outer and inner bark, phloem, cambium, and the first tree ring.