The objective of the research was to characterize the qualitative and quantitative changes in ground and tree vegetation within 10 years since the beginning of observations at Level II forest monitoring plot in Valgunde. Tree height, diameter, stem volume, radial increment, crown condition and cone yield were determined, as well as crown projective cover of each plant species was estimated. To study bioindication, the average Ellenberg’s and Düll’s indicator values for the monitoring plot were estimated. Species composition in the Level II monitoring plot in Valgunde is typical for Myrtillosa forest type – there is a distinct moss layer, in which Hylocomium splendens and Pleurozium schreberi predominate, and Vaccinium myrtillus is the most common in the herb layer. Shrub layer mainly consists of spruce seedlings, and the tree layer – of Scots pine. Changes in vegetation over 10 years are insignificant. It can be explained with no forest management activities occurring within the observation plot, such as logging or fertilization, and it may take a longer time to observe significant changes. Tree stand indicators correspond to the average in Latvia in Myrtillosa type forests, but the tree volume is higher in Valgunde monitoring plot.

The general purpose was to study productivity of organic grasslands and compare it with productivity at a conventional farm under the same or similar climatic and pedologic conditions. The investigation was based on field experiments that were carried out in 5 different regions of Estonia in 2000. In the current research, the DM-yield of sward (on 4 research plots of 5 square m), the botanical composition, soil pHKCL and humus content (by Tjurin) were measured. Also the content of soluble plant nutrients P and K were measured by DL-(Egner-Riehm) method and Ca and Mg- by AL- (ammonium acetate extraction) method.

The paper gives a brief overview and describes the main results of comparison research in grassland management of conventional and organic farms. The aim of this study was to assess yielding ability and biodiversity of leys depending on the nutritive status of soil. The investigation based on field experiments that were carried out in several regions of Estonia: Laeaene (West), Harju (North) and Voru (South-East) county in 2001. In the research on the productivity of grass-clover leys of the first harvest year was measured the DM yield and content, the botanical composition of the sward and the concentration of crude protein on grass. The soil pHKCL and content of organic matter were measured, also the content in soil of soluble plant nutrients P, K, Ca and Mg was estimated by AL- (ammonium acetate extraction) method. The soil profiles were described and soils were classified. The dominant soil types in farms of West-Estonia were Calcic Cambisols and in North-Estonian farms Calcic Gleysols, in South-East Haplic Podzols types prevailed.