Yield, vegetation and succession in reserved fields in Central Finland

51 reserved fields were studied with the harvest method in Central Finland in 1974. 107 vascular plant taxa were identified, having a total oven-dry green biomass of 273.5 g/m2 on the average, and a total mean biomass of 1458.1 g/m2. The amount of the above-ground biomass stays about the same at least for three years after 23 years of increase, whereas the underground biomass increases strongly at least during the first six years, if succession starts after open cultivation. The general tendency in succession at the species level is for the typical weed species of open cultivations to reduce in a few years, and for the species of meadow vegetation to increase both in frequency and abundance. Five vegetation types were distinguished: I) Galeopsis-type, 2) Phleum-type, 3) Anthoxanthum-type, 4) Deschampsia-type, and 5) Elytrigia-type. They can all be placed into a certain succession scheme that is mainly determined by the age, soil and moisture conditions of the reserved field