Investigations of the above- and below ground biomass on permanent plots in a tall herb birch forest community (Lactucion alpinae alliance) were carried out in 1993 and 1994. The results show that the total biomass decreases with increasing scything frequency (not scythed since 1950 - scythed biennially- scythed annually) from about 10-13 000 kg.ha-1 to about 3-5000 kg.ha-1. The ratio of aboveground to below ground biomass also decreases from about 0.8 to about 0.4-0.6. The total number of shoots shows the opposite tendency and increases with increasing scything frequency. The species composition changes from a community dominated by tall herbs as Aconitum septentrionale, Geranium sylvaticum and Angelica archangelica to a more grass-dominated community (e.g. Agrostis capillaris, Deschampsia flexuosa). There are also considerable differences in biomass and number of shoots between the two years. This may partly be due to a methodological bias and partly to fluctuations in climatic conditions.