Lesovedenie

The assessment of phytomass, as the most important characteristic of forest ecosystems, plays a key role in monitoring the global carbon cycle and assessing the state of forests. In order for the species to achieve optimal productivity at the plant level, some proportionality between the functions and phytomass of its components must be ensured. The theory of optimal phytomass partitioning suggests that plants adapt the size of their organs not only to the external environment, but also to the physiological activity of various tissues. According to this theory, it has been established that the share of the component in the total phytomass (i.e., the relative phytomass of the component) is not constant: if in mature trees the largest share of phytomass falls on the stem and the smallest on the assimilation apparatus, then in seedlings the largest share of phytomass falls not on the stem, but on the assimilation organs. In order to establish the age at which the aforementioned trends change, the author’s database on the phytomass of trees belonging to the forest-forming genera of Eurasia was used. Models of changes in relative phytomasses for four coniferous and four deciduous forest-forming genera have been developed in relation to the age and the aboveground phytomass. Their contributions to the explanation of the variability of relative phytomass components amounted to 57–60 and 40–43%, respectively. It is established that with age the positive dependence of the relative phytomass of the stem upon the aboveground phytomass is replaced by a negative one, and the negative dependence of the relative phytomass of the branches is replaced by a positive one. The negative dependence of the relative foliage mass upon the aboveground phytomass by the age of maturity is leveled. The ages of the change of the positive or negative dependence of the relative phytomass of the components upon the aboveground phytomass by the opposite dependence in the studied age range have been established. However, the ages of the change of these rankings vary greatly in different genera, and further research is needed both to clarify the ages of the named shift and to clarify the reasons for such a significant variation. The obtained results showed that the relative phytomasses of the components change with age and phytomass in their interaction, i.e. there is a synergy of factors.

The paper focuses on the dynamic processes occurring in indigenous spruce phytocenoses developing on the territory of one of the large reserves of spontaneous dark coniferous taiga in the European North – the Pechoro-Ilychsky Reserve. The aim of the study was to assess the size structure dynamics of the forest stands and the undergrowth, as well as changes in their vital status in naturally developing spruce stands of the green moss and long-stem moss groups of forest types in the foothills of the Northern Urals (the basin of the upper reaches of the Pechora River). The spruce stands, mixed in composition and complex in structure, form a cyclic uneven-aged type of structure. For the middle taiga indigenous spruce forests, based on the assessment of inequality in the woody plants’ sizes distribution, the results of the long-term structure monitoring of the forest stands and the undergrowth on four permanent sample plots were analysed. In forest stands of different types, a similar dynamics of tree differentiation by trunk volume and undergrowth by trunk height was observed. There is a significant accumulation of small woody plants individuals, with a smooth, evenly fading distribution of their numbers in the direction of size increase. Under the canopy of forest stands there is a continuous regrowth process. According to the data of stationary observations of the vitality and damage degree of trees and undergrowth of spruce forests, based on a visual assessment of a woody plant state according to the characteristics of the crown, a slightly weakened condition of both the upper tree layers of the phytocenosis and the lower – undergrowth was revealed. Spruce stands are at the stage of initial weakening or are already weakened, the undergrowth is predominantly healthy.

A study of the biological properties of the Siberian pine (Pinus sibirica Du Tour) seeds was carried out. Four seed categories were used in the work, differing in size: large (11–14 mm in length), medium (9–10 mm), small (7–8 mm) and very small seeds (<6 mm). The seeds quality study using the X-ray and the histochemical analyses showed that the size of the seeds can indicate their defectiveness. Fractions of small and very small seeds of Siberian pine turned out to be completely sterile, most of the seeds of large and medium fractions were viable. Cytoembryological studies have shown that in trees that form empty and underdeveloped seeds (fractions of medium and large seeds), disturbances in the embryological structures development can be observed. These disturbances take place at the stage of gametophytogenesis and the archegonia development. In trees with large seeds, gametogenesis proceeds without deviations, four archegonia are formed in the ovules, and polyembryonic seeds are formed (up to 16 embryos in the germinal canal). In Siberian pine trees with a one-year reproductive cycle, the seed size varies from very small to large. In these trees, the development of the female gametophyte is completed and archegonia are formed. However, in the ovules of trees with a one-year reproductive cycle, fertilization of eggs does not occur and seeds without an embryo are formed. During the period of stratification (four months), in most seeds of the medium and large fractions the intraseed, growth of the embryo was completely completed. In in vitro culture on MS medium with a low concentration of hormones, the growth of the germinal axis was carried out in seven days of cultivation. The embryos germinated successfully. Thus, based on experiments on the Siberian pine embryos cultivation, it can be concluded that the seeds of this species can enter organic (morphophysiological) dormancy. When creating optimal conditions for germination (nutrient substrat, temperature 24 ± 1°C), Siberian pine seeds are able to germinate.

The article presents the species and structural diversity of coniferous-broadleaved forests of the Pshekha river – the largest tributary of the Kuban river. All in all, 7 main types of forest were identified and described: fir-beech fern-forb forest, fir-hornbeam blackberry-forb forest, aspen-hornbeam honeysuckle-small-herb forest, hornbeam-black alder nitrophilic-tall-herb forest, hornbeam-oak rhododendron-blackberry forest, hornbeam-beech blackberry-forb forest and hornbeam honeysuckle-blackberry forest. The composition of the forest flora of the Pshekha river includes 270 species, including 221 species of vascular plants and 49 species of mosses. Floristic diversity of coniferous-broadleaved forests of the Pshekha river is inversely related to the crown density of the stand and the proportion of oriental beech (Fagus orientalis). The highest species saturation was noted in the hornbeam-black alder nitrophilic-high-grass forest type, the lowest – in the fir-beech fern-forb type. Ecological and coenotic structure of coniferous-broadleaved forest types of the Pshekha river depends on the height above sea level, which determines the indicators of the average annual precipitation and average annual temperature – with a decrease in altitude above sea level. m. the proportion of boreal species in the composition of the flora decreases, while the proportion of nemoral and meadow-edge species increases. In the coniferous-broadleaved forests of the river. Pshekha, 11 species of earthworms were identified, belonging to four morpho-ecological groups: epigeic, epi-endogeic and endogeic, as well as anecic. In forests with a high quality of litter (hornbeam-dominated), the greatest contribution to the biomass is made by epigeic (up to 41%) and endogeic (up to 45%) groups of earthworms. In forests with low quality litter (fir- and beech-dominated), the share of endogeic earthworms is high (up to 66%). Anecic worms are mostly confined to forests on moist soils. In all types of forests, Crimean-Caucasian endemics make a large contribution to biomass and abundance: polymorphic species D. schmidti, anecic D. mariupolienis, as well as Mediterranean species: litter D. attemsi (often inhabiting oak and hornbeam deadwood) and proper soil A. jassyensis. Cosmopolitan species (D. r. tenuis, D. octaedra) are numerous among the epigeic worms and often inhabit deadwood of coniferous tree species.

Projects aimed at achieving carbon neutrality will increasingly determine the direction of the global economy. Their implementation will cause not only an increase in the cost of energy supply, but also lead to additional extraction of fossil fuel and an increase in demand for electricity. Under these conditions, the Russian Federation should adjust the vector of its development and use natural resources, taking into account the accumulated experience in solving complex problems based on a systematic approach. The transition from a fragmented approach to the integrated use of the afforestation and reforestation sequestration possibilities is the way to maintain the structural stability of the domestic economy. It is shown that the reforestation and afforestation on areas equivalent to those occupied by the Volga-Kama HPPs’ cascade’s reservoirs will result in an increase in carbon dioxide absorption comparative to a decrease in emissions when the energy from the gas-powered thermal power plants will be replaced by hydropower. Also presented are the numerical estimates of the increase in CO₂ sequestration resulting from the reforestation on the area of an ancient lake, which used to occupy a significant part of the Mologo-Sheksninskaya lowland at the end of the ice age, in case of a change in the level of the Rybinsk reservoir.

The relevance of the topic is due to the growth of urban agglomerations, resulting in the problem of preserving natural objects that perform important environmental, aesthetic, recreational functions. One of such objects is the “Severny Les” park, created in 2014, which has been chosen as the subject for the study. The park is located in the Kominternovsky district of Voronezh, its area is 51.57 hectares. The park has the status of a nature park, its territories (together with water areas) include natural complexes and objects of significant ecological and aesthetic value and intended for use in environmental protection, educational and recreational purposes. The main purpose of the study was to determine the recreational value of the park. In the work, recreational and sanitary-hygienic assessments were carried out, the stages of digression and the plantations’ stability classes were determined. The description of tree and shrub vegetation was given together with the identification of its condition. Based on the object’s complex assessment, functional zoning was developed, which made it possible to identify the problems of the territory, reveal its potential, and carry out basic transformations. A range of plants for the park’s landscaping was recommended, taking into account age and seasonal variability, decorativeness, resistance to the park’s conditions and anthropogenic stress.

Lichens and other terrestrial photosynthetic unicellular organisms of the planet consume nearly 14.3 billion tons of atmospheric CO₂. Due to climate change, such important components of the forest ground cover as lichens are very vulnerable. This study evaluates the photosynthetic activity in widespread lichens by measuring the indices of net photosynthesis, dark respiration, and prompt fluorescence. Hence, cryptogams of pine forests in Central Siberia near the Zotino tall tower observatory (ZOTTO) are characterized as highly active. Cladonia stellaris (Opiz.) Brodo and Cladonia rangiferina (L.) are the main representatives of ground cover species. The purpose of this study was to determine the photosynthetic activity in dominant species of ground cover lichens during a growing season. We found the seasonal dynamics of photosynthesis with the lowest values being observed in June, and the highest ones in August. Dark respiration peaks in June and is the lowest in September. Fluorescence values are within the range of 6.7 ± 0.3. The species under study that grow on podzol soils in pine forests show fast kinetic activation.