Xylogenesis dynamics in sessile oak during 2007

We investigated seasonal dynamics of wood formation in sessile oak (Quercus sessiliflora Salisb.) during the vegetation period of 2007, using light microscope. Divisions in the cambium already started at the end of March when the number of cells increased up to 10-11 layers. Maximal cell production was recorded in the second half of May when more than 100 ?m of the increment was formed per week. Cambial activity ceased by mid-August and the number of cambial cells diminished to 5-7 layers. However, secondary cell wall formation and lignification of terminal late wood cells took place for additional 4-5 weeks. The dynamics of wood formation in sessile oak differs from radial growth patterns of conifers