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Numerical simulation has shown that the effect of CO addition in small quantities to rich dimethyl ether mixtures is due only to the physical contribution to the normal flame speed. There is no chemical contribution. Therefore, extrapolation of linear regions of the dependences of rich flammability limits to zero concentrations of nitrogen, CO₂, and CO gives the same value of the dimethyl ether concentration. The relationship between the chemical and physical contributions of the effect of a fixed CO additive was obtained over the entire range of dimethyl ether concentration in the mixture with air. The addition of CO affects the occurrence of superadiabatic temperatures in the dimethyl ether flame in the same ways as the addition of inert CO₂ and N₂.

Experimental studies and kinetic analysis of ignition in air of stoichiometric mixtures of methane with carbon monoxide at temperatures below 1000 K and pressures of 1-15 atm showed the complex nature of the influence of mixture composition, temperature and pressure on the ignition delay. For mixtures with different carbon monoxide contents, pressure has different effects on ignition, and the values of the effective ignition delay energy of these mixtures are very different, indicating serious changes in the process mechanism when changing all the above parameters. The most obvious changes are associated with the influence of these parameters on the formation reactions and subsequent kinetics of hydroperoxide radicals HO₂^•, including the role of their interaction with carbon monoxide. It is also necessary to take into account the contribution of highly exothermic processes involving carbon monoxide to the heat balance of the ignition process of such mixtures. Information on the influence of the main parameters on the ignition of mixtures of methane with carbon monoxide at low temperatures is necessary to ensure the safety of technological processes for the production and use of synthesis gas and hydrogen, the operation of coal mines, as well as the optimization of detailed kinetic mechanisms of the oxidation of light hydrocarbons.

The article analyzes the viability and silvicultural and reclamation efficiency of stands of silver birch ( Betula pendula Roth), black poplar ( Populus nigra L.) and laurel poplar ( Populus laurifolia Ledeb.) at the age of 33 years, growing in forest belts of checkerboard and row planting methods. Using modern research methods, temporary trial plots were established. It has been established that on chestnut, poorly developed and sandy loam soil with deep groundwater, stands of the noted tree species are at the stage of degression. The best viability (1.8 points) with planting safety of 57.5 % is typical for birch stands created by the checkerboard planting method. The worst viability (4.5 points) and low (14.7 %) preservation are distinguished by stands of black poplar, created by the same checkerboard planting method. The surveyed forest stands are characterized by a weakened and severely weakened vital state. The total lifespan of silver birch in the Koibal steppe can reach 45 years, and black and laurel poplars - no more than 35 years. The protective and silvicultural and reclamation properties of birch forest belts are not sufficiently expressed, they have a satisfactory (3a points) silvicultural and reclamation assessment, they require partial reconstruction and the resumption of agrotechnical care at the edges of the forest belts. Poplar forest belts have completely lost their protective and silvicultural-reclamation functions, correspond to a low (1 point) silvicultural-reclamation assessment, and need to be uprooted and replaced.

Due to climate change, many species of coniferous trees, which are the main forest formers of the forests of Western and Eastern Siberia, have shifts in both latitudinal and altitudinal boundaries of the range. This study is devoted to determining the features of photosynthetic activity and pigment composition of Siberian pine needles growing in the area of the Ergaki ridge of the Western Sayan, during the period of recovery from the state of winter dormancy. Young Siberian pine trees ( Pinus sibirica Du Tour) growing at different heights above sea level were taken as objects of research. In the area of Lake Oyskoe on the territory of the Ergaki Nature Park in the spring of 2023, a transect with four test areas was laid, crossing the timberline during the transition from the mountain taiga to the rocky-tundra area. Single specimens of Siberian pine , spread above the timberline, have a number of ecophysiological features that allow them to survive in fairly harsh conditions. Such features include a greater depth of winter dormancy, when trees in the phase of forced dormancy react more slowly to temperature increases, compared with trees growing below the timberline. For them, apparently, winter-spring thaws will not pose a danger. Strong insolation at low temperatures, characteristic of open mountain slopes in late winter and spring, is also not critically dangerous for the advancement of Siberian pine above the timberline, due to the predominance of carotenoids in the pigment complex of their needles during this period.

The features of individual variability of morphometric characteristics of the shoot of Siberian fir ( Abies sibirica Ledeb.), growing at different altitudes on the northern macroslope of the Eastern Sayan in the territory of the Krasnoyarskie Stolby National Park, were studied. Siberian fir on the northern macroslope of the Eastern Sayan is found over the entire range of absolute heights - from low mountains to middle mountains. However, it was found as part of a tree stand in various forest types and does not demonstrate a strict phytocenotic association. Apparently, in this area, Siberian fir is in conditions of its ecological and phytocenotic optimum. The annual growth and leaf cover of the shoot varies at an average level, the length of the needles - mainly at a low level, the width of the needles - at a very low level. The length and width of needles, characterized by low variability, can be recommended for diagnostic purposes. A comparative analysis of the average values of the studied characteristics showed that as the absolute height increases, there is a statistically significant decrease in the annual growth, length and width of Siberian fir needles, as well as an increase in the shoot cover. Fir shoots from the Krasnoyarskie Stolby National Park (Eastern Sayan) are distinguished by higher values of annual growth, shoot cover and needle length, while the width of the needles is greater in fir from the Western Sayan. The observed differences may be associated not only with climatic differences in the regions, but also with different phytocenotic confinement of the studied cenopopulations. The annual growth of shoots and their cover significantly depend on the meteorological conditions of the year. A close correlation of these characteristics with the July temperature and air humidity in May and July is shown. There was no significant influence of weather conditions of the year on the morphometric characteristics of fir needles.

The formation of sustainable tree stands during timber harvesting in mature and overmature stands is largely determined by logging methods used and the technological methods for their implementation. In clear-cutting, this, first of all, depends on the degree of preservation of undergrowth, small size trees and trees that are not subject to felling, ensuring accelerated reproduction of stands in cleared areas. Among logging technologies, this is facilitated by narrow felling technological schemes with logging widths of 15-30 m, which allow maintaining undergrowth and undergrowth of over 60 %. In selective felling, the main emphasis is on the formation of valuable stands of a certain density, age and structure due to the intensity and uniformity of the selection of tree species, the preservation of forest growing environment and the growing conditions of the main forest-forming species. Here technologies can be used that allow for a uniform selection of trees over an area while maintaining post-harvesting density of at least 0.5. The goal of the study was to identify optimal techniques and methods of felling during timber harvesting, ensuring the formation of sustainable post-logging tree stands for the main forest formations of the Russian Far East.

Behavioral reactions that weaken the limiting influence of abiotic factors play an important role in achieving compliance of plant functioning with the environment. One of such adaptive reactions is the compensation (substitution) of the action of one factor by the influence of an other. It is known that with the deterioration of growing conditions, the proportion of the assimilation apparatus in the total phytomass increases, thereby compensating for its reduced activity in these conditions. In general, an increase in the density of needles on shoots increases the absorption coefficient of photosynthetically active radiation (PhAR) and reflects an increased compensatory ability in unfavorable abiotic conditions. The purpose of our study was to confirm or refute the hypothesis of factor compensation by the example of changes in the share of needles in shoots of Scots pine ( Pinus sylvestris L.) in the gradient of the sum of effective temperatures geographically distributed in Northern Eurasia. Based on the author’s database, which includes 490 definitions of the percentage of needles in the mass of shoots, a regression model of the dependence of needle percentage upon the age, stem diameter and the sum of effective temperatures is constructed, explaining 40 % of the variability of the desired indicator. An inversely proportional dependence of the percentage of needles in shoot phytonass on the sum of effective temperatures has been established. Thus, the hypothesis of compensation of the reduced sum of effective temperatures (and the corresponding PhAR) by an increase in the percentage of needles and the corresponding absorption coefficient of PhAR is confirmed.

The character of restorative forest successions after catastrophic disturbances is largely determined by their initial stage. The natural regeneration of tree and shrub species has been investigated, taking into account the influence of herbaceous vegetation on this process in two clear cut area at the site of the 2017 windfall in near Moscow Region. The type of clear cut area is mixed herbs with predominance of reed grass. The soil-forming rocks are sandy loam and light loam. Accounting for the natural renewal of tree and shrub species and soil vegetation cover was carried out on circular test plots with an area of 10 m², located at different distances from the edges. 102 species of herbs were found. Clearings differ in the species composition of herbaceous vegetation. The Jaccard similarity index was 37.3 %. This difference is due to the presence of rare species, the most represented species are found in both clear cut area. In clear cut area No. 1, 17 species of trees and shrubs were noted, and in clear cut area No. 2, 13 species. Scots pine ( Pinus sylvestris L.), silver ( Betula pendula Roth) and moor ( Betula pubescens Ehrh.) birch, and aspen ( Populus tremula L.) dominated in both clearings. Successful regeneration of pine trees was noted at a distance of no more than 50 m from the forest wall. Small-leaved species are found throughout in the clear cut area. The amount of natural reforestation of pine significantly exceeds the amount of birch and aspen, at the same time, pine is much inferior to these species in height. Among herbaceous plants, the renewal of pine is most hindered by the reed grass ( Calamagrostis arundinacea (L) Roth.), and among deciduous species - aspen. For the successful formation of pine stands, it is recommended to carry out thinning.

At the beginning of the 21^st century in St. Petersburg, the number of species of trees and shrubs that have entered a reproductive state has noticeably increased. A number of them produced seed offspring for the first time over a long period of introduction. In such conditions, when the levels of adaptation change so noticeably and the biological characteristics of different plant species manifest themselves differently, the role and importance of conducting and processing long-term series of continuous phenological observations undoubtedly increases. During the period of continuous phenological monitoring (1980-2022) in the Botanical Garden of Peter the Great Komarov Botanical Institute Russian Academy of Sciences established that against the backdrop of climate warming in St. Petersburg, which began in the late 1980s, biological cyclicity, according to N. E. Bulygin, manifests itself in the alternation of early warm periods (1989, 1990, 1992, 1995, 2007, 2008, 2014, 2015, 2016, 2019, 2020, 2022) and late cold years (1980, 1982, 1985, 1987, 1996, 1998, 2003, 2004, 2006, 2011, 2012, 2013), which is reflected on the reproductive activity of woody plants and their ability to survive winter conditions. For the period 2001-2022 238 species entered the reproductive state, many of which had previously been in a vegetative state for decades. The improvement in the reproductive sphere of plants is especially noticeable after the abnormally warm winter of 2006/07; it intensified in 2015. This year and 2020 became the warmest during the period of instrumental meteorological observations in St. Petersburg. 50.8 % of cases of the first flowering and fruiting occur in early warm years; and only 16.4 % of cases - in late cold years. When summing up the results of introduction and assessing the prospects for breeding woody plants for urban floristics, it is necessary to take into account the cyclical climate of the region, the seasonal rhythm of plant development and their rhythm-adaptive connections.

Forest governance around the globe has been making positive progress in the sense of resource management in the last decade. However, differences in legal systems and policies cause some difficulties in advancing towards the common goal of forest sustainability. This study is aimed to contribute resources sustainability by comparing forest laws in different legal systems so, as to get good governance and practice examples. The legal systems discussed have been determined as Romano-Germanic (Civilian), Anglo-Saxon, Islamic, and Socialist law. To represent these legal systems Germany, Canada, Nigeria, the People’s Republic of China, and Türkiye have been selected. Forest laws of those countries examined and discussed for definition of forest, ownership types, and protection. It has been concluded different legal systems has an important effect on forest perception and the spatial area of forests. The sustainability approach in the Chinese Forest Law has more positive effects on the forest when compared to other laws. That kind of perception of forest law may lead better forest governance and could be the best example for the rest of the world.