Home – Home – Jornals – Siberian Journal of Forest Science 2020 number 1

Six compartments of burnt areas from different years were studied in larch, pine-larch and larch-pine dwarf shrub-moss-lichen sparse forests and light forests of the Nadym district of the Yamal-Nenets Autonomous Okrug. The new dendroсhronological method of dating of forest fires based on indicators of a variation of parameters of width of year rings is used. It showed that all biocoenoses during the life of trees were repeatedly exposed to fires, which frequency on different areas makes from 1 to 3 in a century. The beginning of the growth of new generations of trees usually comes in the years following the passing of fires and coincides with the phase of enhanced post-fire growth of the surviving instances of older generations. On all of the examined burnt areas, there is a natural regeneration of tree plants: on fresh burns (prescription of the fire 2 years) it is represented only by a vegetatively renewing birch and its self-sowing; on old ones (prescription of the fires 12, 17 and 22 years old) - the undergrowth of conifers prevails. The total number of reliable undergrowth of tree plants of all species varies in different areas from 0.7 to 10.0 thousand pcs / ha. The total number of undergrowth with an increase in the age of burnt area decreases, and older generations begin to dominate in composition. This is due to the restoration of living ground cover, which prevents the germination of tree seeds. The composition of the undergrowth and the ratio of species in it is determined by the presence of seed trees. In sparse forests, where Scotch pine is present in the composition of the remaining stand, it regenerates better than the Siberian larch, which leads to a gradual change of larch stands to pine. If there are mature the Siberian stone pine trees on the site or near it, there is an active natural regeneration of this species in the burned area.

Recreational activities on natural territories put great pressure on ecosystems with the human impact being very uneven. The paper reports on experience of analyzing and monitoring the recreational impact on the forest area of the Kravtsovskiy waterfalls in the south of the Russian Far East. Autumn weekends have been found to show the highest attendance of Kravtsovskiy waterfalls with hundreds of people coming to relax there. Forest ecosystems have been revealed to experience heavy recreational impact. An effective way to conserve and to use this territory rationally is to include it into the structure of a national park or reserve. The recreational impact on the ecosystem should be evaluated and monitored at different levels. At the level of the considered territory as a whole (it may be a macro-landscape or a meso-landscape in natural or arbitrary boundaries) the most important tool is a map of the digression stages, which is a fairly simple model of the territory, but it is a good basis for characterizing, assessing and monitoring the state of the ecosystem and the recreational impact on it. Trails and picnic sites are representative areas of maximum impact of holidaymakers on this map. At the level of individual biogeocoenoses or biogeocoenotic parcels, in particular for trails and sites, ecologic-coenotic transects (profiles) should be used for detailed phytoindication of recreational impact. As indicators one can choose all plants or, e. g., only adolescents of tree species. Indicator parameters of plant species (abundance, height, vitality, ecological-coenotic features, recreational pressure tolerance) allow us to identify areas in different digression stages within the transect and biogeocoenosis as a whole.

Thinning is the main activity in the system of sustainable forest management. They define target indicators, which will have forest stands by the final cuttings. Scots pine Pinus sylvestris L. is the most widespread of economically valuable species. The aim of the work was an experimental verification of the probability of a species succession in typical pine habitats of the southern taiga of Western Siberia. The experimental area is located in the Timiryazevskiy forestry unit of the Tomsk Oblast, where green-mossy pine forests were cut down in 1999-2001. In 2010, thinning was carried out on young stands on an area of about 45 hectares. The thinning was carried out with a cutting of unwanted trees with strips of 5 m wide, i. e. cutting intensity was 50 %. As a result of studies, it was found that in the control plots, mixed stands with a share of scots pine about 40 % were formed. Aspen predominates in the stand composition, which is almost completely affected by rot of the trunk (90-100 %). Scots pine is much behind growth in aspen (2 times). The radial growth of trunk also indicates the suppression of the Scots pine. The two tier of stands is formed in the strip with thinning, where the upper tier is occupied by Scots pine, and the subordinate is aspen. The important stage in the creation of a new forest generation is the settlement dynamics of the felling area. For Scots pine, the pulsed nature of regeneration is confirmed - over a short period of time (3-4 years). Deciduous trees have a longer reforestation period (6-7 years). The increase in height in the strip with thinning turned out to be significantly higher than in the control plots (40-50 cm versus 20-30 cm). The developed system of felling, which consists in carrying out the first intake of non-commercial thinning at the age of 6-7 years old Scots pine and the second intake of thinning at 10-11 years, ensures the formation of Scots pine young stands.

Live ground cover and litter play an important role in forest ecosystems, especially in northern boreal subzone where phytomass of understory vegetation and its annual turnover are comparable with those of tree stands. However, there are practically no quantitative estimates of live ground cover biomass and forest litter stock for different types of forest ecosystems in the Central Siberia permafrost zone. The study was conducted in the Central Evenkia which territory has well developed low-mountain relief. The last one contributes to microclimatic diversity and thus differences in dynamics of phytomass accumulation and plant residues’ decomposition between landforms. The litter stocks and live ground cover biomass were assessed for forest stands growing in the lowlands, on the slopes of northern and southern exposition and on the uplands. The studied ecosystems have been unaffected by forest fire for more than 50 years now. The main forest-forming species of all forest phytocenoses except for upland is Gmelin’s larch Larix gmelinii (Rupr.) Rupr. It was found that among the studied ecosystems the highest values of live ground cover biomass and forest litter stock occur in the lowlands and on the northern slopes. Such distribution is the consequence of these landforms’ hydrothermal conditions: permafrost here lies closer to the surface and soils are permanently wet. These factors create favorable conditions for moss-lichen cover growth but retard decomposition of plant residues leading to forest litter accumulation. It is noted that mosses and subshrubs make the major contribution to the live ground cover biomass in the studied ecosystems. The main components of litter in forest phytocenoses of the Central Evenkia are fermented plant residues.

Amur maackia Maackia amurensis Rupr. (Leguminosae) is a valuable, relict and rare plant in the flora of Russian Far East, which has now acquired importance as a promising medicinal plant, based on which raw materials they develop new highly effective drugs, while it rarely used in urban greening. It belongs to shade-tolerant rocks, it is of little demanding to soil fertility, because of the superficial root system, and single-standing trees do not withstand wind loads. In connection with the increasing loads on the natural resources of this species when harvesting plant materials, there is a problem of developing the basics of laying the plantations and growing (cultivating) in nurseries or specialized farms. Amur maackia in places of natural growth multiplies mainly by seed, although it also forms root growth. However, in nature, it does not always form seeds, which makes it difficult to reproduce. Evaluation of the quality of seeds and methods of their germination is relevant for the development of reproduction methods and the laying of plantations, in order to create a resource base of a valuable resource type. Modern methods of microfocus radiography of reproductive diasporas allow to quickly determining the quality of seed. Amur maackia seeds remain viable for a long time (up to 3-5 years). Seeds for laying nurseries should be collected in places of natural growth, pre-selecting the largest, well-made, removing small and defective ones from the collected lots. With an increase in the shelf life of seeds for germination, various methods should be applied: scalding with hot water, treatment with concentrated acid, or soaking in a 3 % solution of hydrogen peroxide; for production purposes, it is best to carry out under the winter sowing.

It is possible to determine specific periods in plants during the vegetation period making phenological observations. When making phenological observations, one can be collect information about occurrence time of some events, such as sowing, germination and bud bursting. Particularly, this evidence will contribute s to the selection of species in site conditions, when making decisions about the species to be left in the field. Therefore, it is important to know blossoming time and lifespan of flowers during the seasons. If coloration of the plants to be used in the landscape design is known to depend on the season, much better compositions with the plants can be created. The aim of the paper is to reveal the differences in the beginning of vegetation of some native and exotic plant species found in the campus of Karadeniz Technical University. In this study, bud bursting times of 19 species of bud bursting dates, including 10 native trees, 5 exotic trees, 2 native shrubs and 2 exotic shrub species were investigated during the 4 phases. Thus, when observations were made for the times from swelling of the buds to the completion of the bud burst, it appeared that the bursting period for Acer platanoides L. was completed in the longest time and those for Carpinus betulus L. and Liquidambar orientalis Mill. - over the shortest time from the native species. The same period for Wisteria sinensis (Sims) DC. was completed in the longest time, while for Prunus serrulata Lindl. «Kandzan» it was completed in the shortest time for the exotic species.