Table 13. Statistically significant correlations observed between studied vessel characteristics and a) densities of rays and axial parenchyma cells, and b) thickness of double cell wall of fibres, diameter of fibre lumen, and fibre wall:lumen ratio. Numbers are correlation coefficients. ** significant at 0.01 level, * significant at 0.05 level. CAG – cambial age group, N – number of observations.

a)
Compared characteristics No. of rays No. of axial parenchyma cells
  CAG 1–5 6–10 11–15 16–20 21–25 26–35 1–5 6–10 11–15 16–20 21–25 26–35
N 119 119 119 108 69 47 119 119 119 108 69 47
Diameter of vessel lumen –0.252 ** –0.199 * –0.299 * –0.435 ** –0.351 ** –0.444 ** –0.261 **
No. of vessels 0.335 ** 0.352 ** 0.288 **
Vessel size:number ratio –0.202 * –0.253 ** –0.315 ** –0.364 ** –0.222 *
Vessel area –0.320 *

b)
Compared characteristics Thickness of double cell wall of fibre Diameter of fibre lumen Fibre wall:lumen ratio
  CAG 1–5 6–10 11–15 16–20 21–25 26–35 1–5 6–10 11–15 16–20 21–25 26–35 1–5 6–10 11–15 16–20 21–25 26–35
N 119 119 119 108 69 47 119 119 119 108 69 47 119 119 119 108 69 47
Diameter of vessel lumen 0.287 ** 0.458 ** 0.395 ** 0.456 ** 0.576 ** 0.470 ** –0.295 ** –0.271 **
No. of vessels –0.326 ** –0.231 * –0.267 ** –0.541 ** –0.466 ** –0.574 ** –0.553 ** –0.465 ** 0.371 ** 0.192 * 0.291 *  
Vessel size:number ratio 0.277 ** 0.185 * 0.201 * 0.413 ** 0.373 ** 0.491 ** 0.561 ** 0.525 ** 0.318 * –0.220 * –0.214 * –0.256 *  
Vessel area