Variation in structure and selected properties of Finnish birch wood. IV.

[摘要] Length variation of fibres and vessels was studied in the branches, stems and roots ofRoth andEhrh. The cells were significantly shorter in the branches and roots than in the stems. There was no significant difference in the cell length between the upper and lower radii of the branches and roots. The length increased from the pith to the surface and decreased in the branches and stems from the base onwards. In the roots the length increased in that direction. The differences between the tree species were small although the cells ofwere a little longer.Betula pendulaB. pubescenseB. pubescens