No 1 (61) (2024)

Introduction. Sustainable forest management in any country is impossible without up-to-date and reliable forest data. At present, one of the methods of forest resource accounting is the state forest inventory (SFI) based on the point estimates of data collected from permanent sample plots (PSPs). The first cycle of SFI in Russia ended in 2020. The large amount of the growing stock data obtained by using the sample method requires in-depth analysis. The purpose of the work is to assess the variability and accuracy of the average values of the relative completeness of stands and the growing stock volume on the basis of PSP materials, as well as identify the causes of discrepancies between the relative completeness and growing stock estimates calculated on the basis of data provided by the State Forest Register (SFR) and the materials of the first cycle of SFI carried out in 69 constituent entities of the Russian Federation. Objects and methods. The object of the study was the forests of the Russian Federation. The research was based on the SFR materials as of January 1, 2023 and the results of measuring 57.5 thousand PSPs laid down in compliance with the SFI methodology. The sample data were analyzed using the Abbe criterion, the Thompson's rule, t-distribution, cumulative curves, and regression models. Results. Tests for homogeneity of the SFI PSP taxation indices were performed along with testing the hypothesis on the equality of the relative completeness averages computed on the basis of SFI and SFR materials using the t-test for statistical significance of the difference at a significance level of 0.05. The causes of discrepancies between the growing stock estimates based on the SFR and SFI data were explained. Conclusions. On the whole, for the generalized aggregates of the relative completeness area-weighted averages in 69 constituent entities of the Russian Federation, variability is 47.5 % (21.6-103.9 %) according to the SFI data and 27.1 % (2.4-30.9 %) according to the SFR data. For 30 Federal subjects of Russia, the relative completeness estimates based on the SFI and SFR data do not differ significantly at a significance level of α = 0.05, while for the remaining 39 Federal subjects, such differences have been statistically proven. The accuracy of the relative completeness estimation by constituent entity of the Russian Federation has been determined. It ranges from 0.2 to 3.6 % according to the SFI PSP data, and from 0.1 to 1.0 % according to the SFR data. For the Russian Federation in general, based on the SFI data, the accuracy of the growing stock volume estimates is 0.25 % and the accuracy of the relative completeness estimates is 0.20 %.

Introduction. The amount of stem wood of appropriate quality for industry is declining steadily, and there is a need for the effective use of tree branches in the production of technological chips, cellulose, and chipboards. Since the basic density of the branch bark is significantly lower than that of the branch wood, the share of the bark in the mass of branches affects the quality of products made from tree branches. On the other hand, the bark of trees, along with its protective functions, performs important physiological functions related, in particular, to the moisture conductivity of the inner part of the bark and the moisture capacity of its outer part, and recently there has been growing interest in these ecohydrological processes of the tree canopy. The purpose of the study. In this study, the first attempt was made to develop the models of the share of the bark in the phytomass of branches in natural pine forests and plantations. Objects and methods. The object of the study was pure pine forests of natural and artificial origin of the island forests in the steppe area of the Turgay Depression. The analysis involved a total of 482 model trees taken from 48 sample areas. Results. The analysis of the dependence of the bark share in the branch phytomass on the tree age and stem diameter at 1.3 m above ground (at breast height) revealed that these variables explain 71 and 91 % of its variability in natural pine forests and plantations, respectively. The variation in the percentage shares of the bark in natural pine forests and plantations was found to be associated with both the tree age and the stem diameter. Conclusion. The developed regression models of the relationship between the bark share in the branch phytomass and the dendrometric parameters of trees in natural pine forests and plantations showed differences in the share of the bark depending on the origin of stands and the dendrometric parameters of trees.

Introduction. Studies of natural forest regeneration in the burnt areas of 1921 and 1972 showed that pine regrowth appears not only due to the fall of seeds from the crowns of surviving living trees, but also from the cones of trees killed by fire. The quantitative and qualitative parameters of pine seeds after fire exposure were established experimentally and confirmed during a survey of pine forests in 2021. Combining the harvesting of pine wood in burnt forests with the use of the natural regeneration potential of pine requires a technological solution. The purpose of the study is to substantiate the technology for harvesting timber in commercial fire-damaged pine forests and evaluate it based on the time it takes to complete the technological elements. The objects are the processes of logging operations that promote the natural regeneration of pine in commercial fire-damaged forests. The research methods are analysis and synthesis of technologies for machine harvesting of timber materials in commercial fire-damaged pine forests, and statistical processing of the time study results. Results. The analysis made it possible to identify new technological methods for harvesting timber that use the primary post-pyrogenic regeneration potential of pine for its natural recovery. As a result of the synthesis, a new technical solution was obtained – a method for preparing assortments using manipulator-type machines in commercial fire-damaged pine stands, ensuring the natural regeneration of pine. Conclusion. The proposed method of logging ensures the harvesting of assortments in commercial fire-damaged pine forests while preserving the seed material in the logging area. The increase in the average cycle time for processing one tree using the proposed method is not significant and does not lead to a significant reduction in harvester productivity.

Introduction. The Mediterranean forests provide wide range of social and economic benefits for the local communities. This is especially true for Syrian forests, which are under influence of the crisis that the country suffered from. In this respect, there is need in more precise technologies for forest inventory and monitoring for sustainable forest management. The aim of the research is to determine the woody production and growth characteristics of Cilicican fir (Abies cilicica) trees that are found in the Lattakia Governorate's Fir and Cedars Reserve of Syria. The object of research. Shuh forest is located in the northern part of the Syrian coastal mountain range, on the western slope of the summit of Jabal Al-Nabi Matta. Research methods. Within the research, remote sensing technology and Sentinel image processing were employed to estimate some forest growth factors, where maps were produced expressing growth factors through multiple regression analyses between sample location variables and corresponding pixel values for all ratios and indicators used. Results and conclusions. All the studied variables showed a significant correlation R that exceeded 0.75 with the wood stock, while the response to the density was lower as it did not exceed the value of 0.33 despite it being significant. The maps of the variables were produced using the derived regression equation for each indicator. The highest accuracy for the wood stock was 77 and 72 % for the average height. As for the estimated accuracy of the model, the average value of the deviation of the values of the variables estimated by the formula from the field measured was 6.08; 9.1; 9.6 and 8–12 % for models estimating the average height, average diameter, wood stock, and base area, respectively.