Certain seasonal changes in balsam fir cambium and its derivatives

Abstract

The seasonal cambial activity of balsam fir producing normal and compression wood was observed. Samples were taken throughout one growing season. Activity was initiated in normal wood with the precocious development of one sieve cell per file 2 weeks before activity was initiated in compression wood with the formation of one new sieve cell per file. Deactivation dates in normal and compression wood were the same. Dating of the phloem adjacent to normal wood can be carried out using crushed sieve cells or an annually formed band of tannin filled parenchyma whereas adjacent to compression wood, only crushed sieve cells can be used. The maximum cambial zone widths in normal and compression wood were 15 and 16 cells, respectively. The final xylem to phloem ratio in normal wood was 14:1 while in compression wood it was 21:1. Time required for development of tracheids was examined throughout the growing season. Growth trends for the radial growth and differentiation phases were studied in both normal and compression wood. Tracheid development in normal wood took between 14 and 33 days while in compression wood it varied between 5 and 49 days.