Ewa Roo-Zielińska

Phytosociological typology and phytoindicator value of young oak and larch forest communities near Pinczów (southern Poland)

Oak (Quercus petraea Liebl.) and larch (Larix decidua Mill.) forest plantations of the study area ‘Mlodzawy’ in Poland were analysed. Changes in the syntaxonomic composition and of Ellenbergs indices (light, continentality, moisture, reaction and nitrogen index) were determinated. The results obtained mostly conform to the assumption that the herb layer of both plantations becomes, gradually with tree growth, more similar to each other and to that of mature oak-hornbeam forests. Such statement is justified by: an increase in the share of species common to both plantation types, a significant increase in the number and cover of the Querco-Fagetea character-species, accompanied by a decrease in the number and cover of other character-species, a general decrease in the share of species with extreme climatic and edaphic requirements, accompanied by a gradual increase in the share of number and cover of species with average demands. From the studies it may be concluded that the developmental mechanisms w which determine the direction and trends of changes in the herb layer are mainly common to both plantation types, whereas tree stand species, in spite of different habit, ecological demands, and effect on soil properties, have only slight modification influence.

Ancient and recent (post-agricultural) forest communities as indicators of environmental conditions in north-eastern Poland (Masuria and Kurpie region)

The paper analyses three forest types belonging to the following associations: (1) fresh pine forest (Peucedano-Pinetum), (2) mixed pine forest (Querco roboris-Pinetum) and (3) oak-hornbeam forest (Tilio cordatae-Carpinetum betuli). They are located in north-eastern Poland. We compared the indicator value of three sets of data: (1) phytosociological releves representing ancient forests (each type/association), (2) phytosociological releves representing the youngest recent forests with the shortest regeneration period (each type/association) and (3) the ‘abstract pattern’ (representing the core of a specific type of plant community with a characteristic combination of species and clearly representing a separate type of ecosystem/association). Three sets of data together with their indicator values/numbers: light intensity (L), soil moisture (F), soil reaction (R), and nitrogen supply (N) according to the Ellenberg scale, constituted the basic material for comparative indicator analysis. The percentage shares of ecological groups of species have been calculated as well as the average indicator values for each of these within a data set. The results obtained show that the ‘abstract pattern’ can be treated as a good measure for the evaluation of ancient forest habitat conditions; it is clearly visible in the mean L and F indicator values of the Peucedano-Pinetum and Querco-Pinetum associations, and also in the N of Peucedano-Pinetum and R of Querco-Pinetum, which are closer to ancient forest than to recent forest. In all cases, we found ecological differences between the ancient and recent forests based on their indicator values. Statistically significant differences of the mean L indicator values between ancient forest and recent forest have been found in three types of forest community.