Xylem formation in Fagus sylvatica during one growing season

The study analyses the activity of cambium and the increment of wood during one growing season of European beech (Fagus sylvatica L.) in the central part (region) of the Drahanska vrchovina, Czech Republic. The research plot was situated at an altitude of 630 m a.s.l. The following parameters were studied: the beginning and end of cambial activity, differentiation of wood fibres and vessels and the total increment of wood during the growing season in six trees. Samples were taken during the growing season of 2010 in weekly intervals from the beginning of April to the end of October. The dormant cambium consisted of 5.3 cells on average; their number rose gradually after reactivation. The maximum number of cells (10 to 14, 9.1 on average) in the cambial zone persisted for 8 weeks; in mid-August the cambium ended its division activity, while the differentiation process continued till mid-September. The first fully lignified vessels were formed 5 to 6 weeks after their formation in the cambial zone. Vessels and adjacent wood fibres were the first elements to become fully lignified. The maximum production of cells (wood increment) was recorded from June 11 to June 24. 57% of the total ring width was formed in June. The mean ring width calculated by means of Gompertz function is 1777 mu m (ranging from 1226 mu m to 2423 mu m).