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Table 2 Timing of main events and characteristics of tree ring formation in stems of Cedrus libani

From: Cambial activity and xylogenesis in stems of Cedrus libani A. Rich at different altitudes

Site O1 T4 T3 T2 T1
Observation (335 m) (1055 m) (1355 m) (1665 m) (1960 m)
Number of cells in dormant cambial zone 7.7 ± 1.0 5.5 ± 0.5 4.9 ± 0.6 5.0 ± 0.5 5.0 ± 0.6
Onset of cambial activity Apr 19 (110) Apr 3 (94) May 3 (124) May 3 (124) May 3 (124)
Onset of growth Apr 30 (121) Apr 10 (101) May 3 (124) May 3 (124) May 15 (136)
Start of cell wall thickening May 19 (140) May 7 (128) June 7 (155) June 7 (155) June 7 (155)
Dormant cambium Sep 6 (250) Aug 26 (239) July 29 (211) Aug 12 (225) Aug 12 (225)
End of growth Oct 10 (284) Oct 1 (275) Sep 24 (268) Sep 26 (270) Sep 26 (270)
Duration of cambial activity (days) 140 145 87 101 101
Duration of xylogenesis (days) 163 174 144 146 134
Total number of xylem cells 120.1 ± 8.5 96.6 ± 34.0 18.0 ± 6.4 31.6 ± 8.3 45.3 ± 13.4
Cell production rate (cells/day) 0.73 ± 0.05 0.55 ± 0.19 0.12 ± 0.04 0.21 ± 0.05 0.33 ± 0.1
Ring width (mm) 3.35 ± 0.65 2.76 ± 0.99 0.55 ± 0.19 1.01 ± 0.38 1.36 ± 0.39
  1. For each site, number of cells in dormant cambial zone, radial growth, total number of xylem cells and cell production rate are presented as means with standard deviations. Numbers in parentheses indicate day of year (DOY) of first observation of the specified characteristics during the growing season 2013.