Vestnik of Volga state university of technology. Ser.: Forest. Ecology. Nature management

In the context of the continuously increasing global role of the planet's forest cover, the study of qualimetric indicators of trees and stands is becoming one of the priorities. The dry matter content (DMC) in plant tissues is an important but insufficiently studied factor. Determination of DMC in the phytomass of trees as a measure of organic matter and carbon concentrations in it is an essential stage in studying biological productivity, phytomass and net primary production of trees and stands. Various fractions of tree phytomass differ in the DMC-moisture ratio, which affects the rate of natural decomposition and the return of carbon and nutrients to the environment. Since DMC in fractions of the aboveground phytomass of forest-forming species of Eurasia have not been previously studied at the transcontinental level, the aim of this study is to identify species-specific features of DMC in the aboveground phytomass fractions, as well as the DMC ratios in its various fractions, for which species-specific regression models of DMC in phytomass should be developed that will describe its dependence on dendrometric indicators of trees in Eurasia. Objects and methods. To achieve this aim,
7,068 indicators of DMC in different fractions of aboveground phytomass of 14 forest-forming species were selected from the author's database on the qualimetry of the main species of Eurasia. Based on them, mixed-type models were built, in which the contribution of dendrometric indicators and dummy variables encoding the belonging of DMC to certain species amounted to 8 and 92 %, respectively. Results. It was found that DMC in the stem wood varies from 72.5 % in Fraxinus excelsior to 42.7 % in Abies alba; DMC in the stem bark varies from 63.4 % in Robinia pseudoacacia to 44.3 % in Picea abies, respectively; DMC in (needle) foliage varies from 52.0 % in Pinus nigra to 28.4 % in Tilia cordata; DMC in branches varies from 69.4 % in Fraxinus to 46.1 % in Tilia, respectively. The difference between DMC in the stem bark and DMC in the stem wood varies from +11.6 % in Pinus nigra to -10.1 % in Fraxinus; the difference between DMC in the branches and DMC in the stem wood varies from +10.1 % in Abies to -10.3 % in Betula pubescens; the difference between DMC in the stem bark and DMC in the branches varies from +18.4 % in Betula pubescens to -6.0 % in Fraxinus. Finally, the difference between DMC in branches and DMC in foliage varies from +31.4 % in Fraxinus to -1.2 % in Pinus nigra. Conclusion. The developed regression models of DMC in phytomass fractions have demonstrated significant differences in DMC between fractions and species, which must be taken into account when assessing the carbon depositing capacity of the forest-forming species of Eurasia.

Logging activities significantly affect the most important functions of forest ecosystems. Forestry intensification implies not only an increase in timber harvest volumes, but also informed planning and control over the implemented activities aimed at forest restoration in felled areas. The basis for carrying out these measures rests on taking into account the landscape-ecological features of the territory where the economic activity takes place. Minimization of the negative impact of logging on ecosystems is taken into consideration in the Forest Code and in the standards of forest management of independent systems of voluntary forest certification. The purpose of the study is to develop and analyze the applicability of individual parameters for assessing the condition of exploited forest sites in the ranking of risks associated with timber harvesting. Materials and methods. The main attention is paid to the quantitative indicators that can be processed using methods of statistical analysis. The set of proposed values is based on the use of geoinformation methods, remote sensing data, and spatial analysis tools. On the example of analyzing the spatial data on the actively developed forest areas in the basins of the rivers Bol. Vizinga, Kobra, Lopyu, Nivshera, and Nizhma of the Komi Republic, additional criteria have been proposed for monitoring and assessing possible risks arising in the wood logging process. Results. In accordance with the purpose of the study, the following criteria for assessing the condition of exploited forest areas have been identified: (1) logging localization in the network of protected areas, (2) areas of clearcuts, (3) presence of intact forest areas in the vicinity of a planned logging area, (4) the mosaic of forest environment, and (5) the indicator of preservation of the water-regulating function of forests. All measured parameters are territorially linked not to administrative or forestry boundaries but to the natural landscape contours included in a single watershed. Conclusion. All of the above parameters can be used as an additional assessment of forest management sites, in land development monitoring, as well as in landscape-ecological planning. The criteria are closely related to the requirements of voluntary forest certification and allow minimizing the negative impact on the ecological functions of forest landscapes in the context of forest management intensification.

The expansion of the scope of safe mechanized logging requires adaptation of forestry equipment to operations in cutting areas with large inclination angles, which, in turn, necessitates the development of new design systems, machines, and mechanisms for solving this problem. However, there is a lack of research on designing and modeling work processes for logging machines in rugged hilly terrain with steep slopes. Known studies are mainly of experimental nature. The purpose of the study is to create a dynamic mathematical model of a rope anchor system, which is a crucial structural component for the safety of wheeled harvesters. Objects and methods. The object of this study is a rope anchor system. The Lagrange method of the second kind was used to construct a system of differential equations for the motion of the mass centers of the main structural components of the harvester and the anchor system. Results. In relation to a three-axle harvester with a 6K6 wheel formula, calculations have been performed to determine the oscillatory processes and dynamic parameters that affect the load on the anchor system and the safety of the harvester's operation during sorting. Conclusion. The dynamic model makes it possible to take into account and systematically analyze a large number of quantitative design and operational parameters of the harvester, as well as the physical and mechanical properties of the soil, which characterize the dynamic behavior and loading on both the structural elements of the anchor system and the harvester itself. One promising direction for further use of this model is the development of practical recommendations for designing efficient and reliable rope anchor systems.

The technogenic transformation and the natural potential of coal industry waste allow the latter to be used in the reclamation of disturbed lands. Technogenic soils are sources of chemical substances, which are included in natural processes and create a special kind of natural and technical systems. At the same time, the most sensitive indicator of the stress impact of anthropogenic factors in an urban environment are woody plants. The aim of the study was to investigate the ecological state of technogenic soils and the prospects of using coal washery rejects in land reclamation in the Arctic conditions. The objectives of the study were to determine the gross concentrations of heavy metals in Vorkuta technogenic soils formed by coal sludge, as well as to assess their impact on the growth and development of woody vegetation. Object and methods.
The object of the study was technogenic soils from flowerbeds installed in the central part of the city of Vorkuta. Microprobe X-ray spectral analysis was used to determine the gross concentrations of heavy metals in the samples. To assess the condition of tree seedlings, a visual inspection of the needle foliage (yellowing and defoliation) was performed, and the young shoot lengths were measured. Results. All of the studied soils are characterized by high total iron content. The zinc content in the soil samples taken from the flowerbeds located along Gagarina St. and near the City Administration building exceeds the approximate permissible concentration, APC (110 mg/kg). The soil from flowerbeds near the City Administration building contains increased copper and cadmium contents as compared to APCs (66 and 1.0 mg/kg, respectively). The concentration of lead in the soil samples does not exceed APC (65 mg/kg). The study of large-sized seedling showed that the best condition of large-sized seedlings of Norway spruce (Picea abies) with no signs of browning or defoliation was observed in the flowerbeds on Gagarina St. and near the City Administration building. Significant damage to needles was found in the sites opposite the ‘Olympus’ and in front of the ‘Vorkutaugol’ JSC building. Conclusion. The study revealed the possibility of using coal mining waste as a soil substrate for flowerbeds of the city. The gross concentrations of heavy metals in the technogenic soils of the flowerbeds located in the central part of Vorkuta were studied. The research of the impact of technogenic soils formed by coal mining waste on the condition of large-sized Noprway spruce seedlings did not reveal any unambiguous patterns.