Vol 109, No 2 (2024)

With the warming of the climate, the intensification of droughts and the drying up of coniferous forests, the number of forest fires is also increasing. Therefore, the study of the post-fire dynamics of stands and prospects for reforestation on burnt areas is especially relevant. The research was carried out in the Central Forest State Natural Biosphere Reserve (southern taiga) on the burnt area formed in 1999 as a result of a thunderstorm. The purpose of the work was: to describe the state of vegetation 22 years after burnout; to find out the characteristics of the stand formed on the burnt area and the possibility of their use for reconstructing the history of disturbancies in old spruce forests. The objectives of the study included: monitoring vegetation changes in the 1999 burnt area; studying the growth of spruce undergrowth in the burnt area; finding out the number and ratio of preliminary and subsequent renewal of tree species; analyzing the distribution and amount of coals in the sample plots (depending on the intensity of burnout and the state of the pre-fire stand). To study the state of vegetation after the burnout of the blueberry-wood sorrel and wood sorrel – nemoral-herb spruce (Picea abies (L.) H. Karst.) forests, 14 sample plots (100 m² each) were laid in the northwestern part of the burnt area. The sample plots covered 1.5 hectares. 22 years after the fire, a mixed small-leaved forest with a predominance of birch and a significant participation of spruce has been forming on the site of burnt spruce forests. Spruce is represented mainly by post-fire renewal. In the undergrowth, the ratio of pre- and post-renewal spruce is about 1 : 3. In the ground cover, a small number of nemoral herb species is recorded, and in the stand and undergrowth – almost complete absence of broad-leaved species. A lot of coals were found in soil digs in 4 sample plots (30%); there were no coals in 3 (20%) sample plots, and small coals in small amount were found in 7 (50%) sample plots.

Assessing the possibilities of identifying the first post-fire generation of spruce in old stands, it must be said that none of the characteristics of a post-fire spruce stand is universal for its recognition. Only a set of features allows to identify the history of the stand. Distinctive features of the first post-old generation: the presence of coals in 30% of samples or more; a large admixture of birch and aspen; a large diversity of the aspen part of the stand; if there are broad-leaved species, they will be much younger than the spruce; the presence of a sharp decline, and then a rise in growths in a significant part of the oldest spruce trees; the main generation of spruce has initial radial growths on an average of 2.1 mm/year, and the absence of synchronous sharp rises of the growths at the beginning of life.

The age of aspen most accurately corresponds to the year of the fire.

About 30 years ago, the species composition of herbaceous plants on the territory of the Peter the Great Botanical Garden was studied. It has changed over the years, and it is necessary to give assessment to this process. Currently, the problem of the appearance and dispersal of invasive plant species, most of which are “escapees” from cultivation, is quite acute in Russia and beyond. The purpose of the research is to identify and analyze changes in the species composition of the spontaneous flora of herbaceous plants in the Peter the Great Botanical Garden over the past 30 years. The objectives of the study included assessing changes in the number of certain alien plant species and their invasive potential. As a result of the inventory, 355 species of vascular plants from 54 families were identified in the modern spontaneous flora of the botanical garden. Among them, the indigenous fraction comprises 248 plant species (70.3%). Compared to 1994, the number of species in the flora of the botanical garden increased by 20%. There was an increase in the group of species escaped from cultivation by 50%, but their abundance does not yet cause concern and only 4 species are recognized as potentially invasive on the territory of the botanical garden.

A targeted lipidomics analysis of four classes of membrane glycerolipids was carried out in two species of Cycadaceae from the genus Cycas – C. revoluta and C. rumphii. The analysis of the molecular diversity of the main phospholipids, which are the components of extra-chloroplast membranes, has revealed archaic features, including a high level of molecular species containing C18:1 fatty acids (typical of Ginkgo biloba), increased relative content of molecular species with odd fatty acids C17:0 and C19:0 (typical of non-seed plants). At the same time, the analysis of the molecular diversity of the glycolipids which are the components of chloroplast membranes, did not find significant differences from most seed plants, which indicates a higher conservation of lipids of a photosynthetic apparatus. The identified features of the molecular composition of glycerolipids of two species of Cycas indicate the prospectiveness of using lipidomics for taxonomic and phylogenetic studies, with the data on the molecular composition of phosphatidylcholines, for which the greatest heterogeneity and species-specificity was demonstrated, deserving the most attention.

An alien North American species, Scirpus cyperinus (L.) Kunth (Cyperaceae), earlier known in Russia only in the Kostroma Region, was found in the Smolensk Region. Characteristics of the locality of the species are given and plant communities with its participation are described. The monodominant phytocoenoses formed by this species are combined into the new ass. Junco effusi–Scirpetum cyperini ass. nov. The new locality of abundant occurrence of the species is removed from its primary range and known locations in Eastern Europe.