Summary A comparative study was carried out on fibre length and microfibril angle in Betula pendula Roth. Fibre length increased and microfibril angle decreased from pith to bark. Microfibril angle remained constant from the 15th annual ring from the pith, to the outermost ring. Fibre length also reached a maximum length at this point although there were some differences at the 30th ring from the pith.