Most of the agricultural lands located on the territory of St. Petersburg are abandoned and are not used for their intended purpose. Farming within the city may be accompanied by risk from the point of view of agriculture, since anthropogenic pressure will be exerted on agricultural crops. The forest biogeocenosis is more adapted to the urban habitat, as it is less demanding to the growing conditions. The transfer of these territories to the category of forest fund lands will allow the creation of additional recreational zones on the territory of St. Petersburg, and will also open up the possibility of implementing forest-climatic projects on them for the purpose of afforestation, which can contribute to the implementation of the state program to achieve carbon neutrality goals. This paper presents a map of the location of all agricultural lands in three categories of condition, as well as information about their areas. The purpose of this study was to develop an afforestation program for carbon deposition for two scenarios. The first one involves settlements only on abandoned agricultural lands, and the second one additionally includes agricultural lands that are currently being used for infrastructure facilities. Calculations were made on the example of a mixed stand with a predominance of spruce, since a mixed stand is more resistant to the effects of external factors, both natural and anthropogenic. The paper describes a method for calculating changes in carbon stocks during afforestation for pools of biomass, dead wood, litter and soil. The results of the calculations were the quantitative determination of additional carbon units, as well as carbon reserves and budget during the implementation of the project under two scenarios.

In the territory of the Sverdlovsk region increasing the number of plat fires in recent years is established. It has been experimentally proved that it is advisable to extinguish plat fires that are not extinguished in the summer autumn period in the winter period. The optimal extinguishing period is the end of February-March. With the development of peat fires, as a rule, multifocal forest fires are formed. The extinguishing of such fires should begin with aeroreconnaissance using unmanned aerial vehicles equipped with thermal imagers. Exploration work should be carried out in cloud weather and temperatures down to minus 10 degrees. It has been established that extinguishing should begin with uprooting trees in the fire center, if any, and moving them to the burned area. Uprooting of trees and subsequent pushing of burning plat is carried out by a 13-10 m bulldozer. When moving the bulldozer is pushing the burning plat with a layer up to 19 cm mixing it with snow and nonburning layers of plat. In reverse movement of the bulldozer, the smoldering plat is compacted in order to cool it better. In on shift, using a bulldozer it is possible to extinguish from 0.5 to 2.0 ha active forest plat fires. This method allowed to put out 28 plat fires in the winter of 2021–2022. Cases of re-ignition of plat in extinguished areas were not recorded.

In modern conditions, a new technology of tillage using excavators is being introduced. The purpose of this study is to evaluate the experience of using excavator tillage to create of forest crops in the taiga forests of the European North of Russia. The research was carried out at 14 clear-cuts in the Arkhangelsk region and the Komi Republic. At the clear-cuts, we laid accounting plots for assessing the quality of forest crops and tillage, and also took soil samples in the root layer. The samples were analysed for soil physical properties using conventional methods. To detect statistically significant differences between the studied samples, we used the t-criterion. Correlations between the studied parameters were analysed using the p Spearman coefficient. In the most of the studied areas, the bulk density of the root layer on the treated strips is somewhat higher, and differs significantly from the indicators in the root layer of the soil in cutting strips (t = 2.1, p = 0.036). Moisture of the root layer on the treated strips does not differ significantly from the indicators in the root layer of the soil in cutting strips (t = 1.9, p = 0.051). Average values of aeration porosity in the treated strips are comparable with the upper horizons in cutting strips (t = 0.02, p = 0.98). The density of planted seedlings as a whole corresponds to the normative indicators laid down in the projects of artificial reforestation. The survival rate of seedlings in the study areas varies from 61% to 98% (84% on average). The highest survival rate is observed in the first year of forest crops creation by containerized tree seedlings, in areas of 2- and 3-yearold crops, the survival rate is slightly lower, especially when planting bare-rooted seedlings. The results of the correlation analysis showed that the porosity of aeration had the greatest impact on survival seedlings (p = 0.564, p = 0.04). In 75% of cases there is a direct relationship. To increase the survival rate of planted seedlings, it is necessary to limit the use of strip excavator tillage on semi-hydromorphic soils.

The concentrations of 9 elements (N, Mg, Ca, K, Na, Mn, Fe, Al, S) were determined in the aboveground parts of two species (Pinus contorta Dougl and P. sylvestris L.) in the mixed plantation in the middle taiga of the Komi Republic. It was revealed that both species, as representatives of the genus Pinus, have much in common in their elemental composition. It has been established that the accumulative series of elements for the studied species is identical and the above-ground parts of the trees belong to the nitrogen-potassium-calcium or nitrogen-calcium-potassium type of chemistry. A high total content of elements is typical for needles, a low one for wood of both species, while about 50% of mineral nutrition elements are N, and 64-78% of ash elements are Ca and K. It is shown that lodgepole pine has a number of chemical features in composition, compared with Scots pine. The main difference is manifested in the higher content of mineral elements in perennial needles (excluding N and S), wood (excluding Mn and K) and bark (excluding Ca) of lodgepole pine. The species specificity of lodgepole pine is manifested in a higher accumulation of Al and Na in almost all above-ground parts of the tree. A feature of lodgepole pine is a lower consumption of nitrogen and potassium by assimilating organs and a higher level of accumulation of mineral elements in wood and stem bark compared to Scots pine.

The aim of the study was to determine the characteristics of the forest formation process under the influence of cattle grazing on abandoned agricultural lands in the conditions of Western Siberia. The study was conducted on former cropland used for grazing and at different stages of the reforestation process. A comprehensive assessment and analysis of the biometric indicators of the stand, ground cover, and soil was carried out, which allows us to determine the genesis of the emerging phytocenosis and predict the dynamics of their development in the Novosibirsk region. Based on the study the hypothesis of the endozoogenic nature of the distribution of Scots pine in pastures in the forest-steppe zone was formed.

The forest stands of urbanized areas play a huge role in human life and perform many environmental, sanitary, hygienic and health-improving functions. The purpose of the study is to study the dynamics of the species composition and stand indicators of pine in urban areas and assess their sustainability. The object of the study is mature Scots pine stands on permanent sample plots in the Forest Experimental Station of the Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. It was revealed that in mature pine stands there is a process of gradual change of pine to broad-leaved species mainly norway maple (Acer platanoides L.) and linden (Tilia cordata Mill.). A regular increase in the stock of deciduous tree species of the forest stand was revealed with a decrease in the stock of pine, and, accordingly, the density of the pine canopy. Therefore, as soon as gaps form in the pine canopy, broad-leaved species such as norway maple, linden, еnglish oak (Quercus robur L.) and white elm (Ulmus laevis Pall.) tend to occupy them. An analysis of changes in stand indicators over a 25-year period of time shows that, in terms of average height, forest stands are approaching their biological limits, and positive dynamics is observed in terms of average diameter, basal areas and stock. According to the ratio of the average height to the average diameter and the basal areas over a 25-year period of time, the stability of the pine stands of the Forest Experimental Station did not change. Mature pine stands show adaptation to a complex of ecological factors of the urban environment. The second tree layer, formed by broad-leaved species, shows the greatest sensitivity to uncontrolled recreational load.

Pine and spruce are one of the main forest-forming species of the Republic of Tatarstan. The success of the annual volumes of reforestation largely depends on the availability of high-quality planting material in the forestries. Annually, for the purpose of reforestation, standard planting material is grown in the amount of 25 million pieces. There are currently 50 nurseries operating on the territory of the region. To maintain their productivity, it is necessary not only to provide plants with all the important macro- and microelements during the period of growth and development, but also to apply various methods that increase the quality of seedlings and resistance to various diseases. One of such effective methods is the pre-sowing treatment of seeds in solutions of biological preparations. Studies to identify the effectiveness of drugs were carried out in laboratory conditions of the Faculty of Forestry and Ecology. Biological preparations produced by Bionovatic were used – Biodux, Organit-N and Organit-P. The treated seeds were germinated in Petri dishes and a hydroponic installation for 15 days in accordance with GOST. During the studies, the germination energy and germination of coniferous seeds were determined, and growth rates of seedlings were measured. The germination of seeds during germination in Petri dishes turned out to be on average 11% higher, the germination energy was 10% higher, and the mortality was 4% lower than in a hydroponic installation. However, in the hydroponic setup, the effect of preparations on growth parameters was 11% higher than in experiments with Petri dishes. According to the results of the experiments, the best result, both on the germination of seeds and on the growth characteristics of seedlings, was shown by the preparation Organit-N. The greatest efficiency of the use of biological preparations was achieved on the seeds of Scots pine.

The results of a one-time survey on 8 experimental plots of young pine of natural origin and forest crops on fellings, under the canopy of the mother tree stand, as well as on former agricultural lands are presented. The soil conditions of different objects are united by a sandy loam mineralogical composition. The average index of viability of pine undergrowth under the canopy of stands is 2.98-3.12, on former agricultural lands – 4.36–4.43. Under the canopy of the stands, there are practically no specimens of pine undergrowth without damage or growth defects, and here the pine is most damaged (up to 70%) by biatorella cancer (Biatorella difformis (Fries.)). The least damage to the snow schütte (Lopodermium seditiosum Mint.) was detected in undergrowth on postagrogenic lands (up to 7%). At the same time, the largest number of moose-damaged specimens, as well as defects such as stepchildren and multibranch whorl, were found on postagrogenic lands and fellings.

The condition of the green areas of preschool institutions located in the north-east of the Russian Plain was studied. The purpose of the research is to analyze the state of green spaces on the territory of preschool educational institutions in the city of Arkhangelsk for compliance with the requirements of regulatory documents. The object of the study is seven preschool educational institutions in the central part of the city of Arkhangelsk, selected at random. The area where the objects are located is characterized by a cold, long, snowy winter and a relatively short, cool and rainy summer. The severity of the climate affects the poverty of the assortment of local tree and shrub species. During the study of green spaces on the territory of kindergartens, the following types of assessment were carried out: dendrological, morphological, bioecological and landscape-architectural. Studies have shown that the green spaces available in the territories do not differ in species diversity. Among the tree and shrub species on the site of one institution, there are only 10-12 species, and some are presented in one copy and in poor aesthetic condition. It is noted that flower cultures do not differ in diversity and bright colors, and in some cases they are not enough at all. It has been established that poisonous species are present in the species composition of woody plants and flower crops, which is extremely unacceptable. The expansion of the range of introduced species of trees and shrubs on the territory of preschool institutions will allow to provide cognitive function, develop aesthetic taste in pupils and improve the architectural and artistic appearance of the territory of kindergartens.

The world is experiencing rapid climate change, and forest growth rates in different climatic zones react differently to it. Understanding the driving forces of these different reactions is crucial for predicting forest dynamics under climate shifts. A common method of assessing forest productivity is the development of the dependence of the stand height upon the age, as well as the assessment of the site index characterized by the stand height at the base age. The dependence of the stand height upon the age began to be supplemented by the introduction of climatic variables into the model, in particular, temperature and precipitation. However, these models did not answer the question of how climate affects the productivity of stands, negatively or positively, but simply showed that the inclusion of climatic and other biophysical variables increases the adequacy of the model. The purpose of our study was (a) to develop a model of changes of average stand height in gradients of geographically distributed temperatures and precipitation on the territory of Eurasia using the materials of 256 sample plots with measured taxation indicators of stands of the genus Populus L. and (b) to show possible changes in average height due to hypothetical shifts in temperatures and precipitation. It has been established that in regions with sufficient moisture, the limiting factor for growth is the lack of heat, and in arid regions, the limiting factor changes, and excess heat becomes it. With an expected increase in January temperature by 1 C, the average height of stands in conditions of sufficient moisture can increase by 3–8%, and in conditions of insufficient moisture – decrease by 4–11%. Accordingly, in the case of a decrease in average annual precipitation by 20 mm in areas of lack of heat, the average height may increase by 2– 10%, and in regions of sufficient heat supply – decrease by 3–15%.

The purpose of this research is to study soil fertility in lawn areas with different microclimatic environmental conditions. Soil sampling was carried out on the territory of six public green spaces in St. Petersburg: Obukhov Square, Ivan Fomin Garden, Murinsky Park, Udelny Park, Yuzhno-Primorskiy Park, Ivanovka River Square. The determination of the main agrochemical indicators was carried out in the laboratory according to generally accepted methods in several repetitions. These studies are carried out within the framework of the interdisciplinary project of the Russian Science Foundation with the support of the administration of St. Petersburg «Lawn as an indicator of a sustainable urban environment and adaptation to climate change». The study of the soil conditions of lawns is one of the important components in the planning of care and maintenance measures. The data obtained showed that the soils in the studied territories are poorly supplied with potassium and phosphorus; nitrogen supply differs, but most soils are poor ones. High positive correlation between the content of available potassium and the content of available phosphorus in the studied soils is revealed.

A dynamic model of the «operator – feller-buncher machine – object of labor – tree» has been developed. The mathematical description is in the form of the Lagrange equation of the second kind. The system of equations is solved for the elastic deformation of the operator's seat back by the Runge-Kutta method, using the MathCAD programming environment. Approbation of the model was carried out on the example of commercially available feller-bunchers machines LP-19A.

Intensive forestry in the boreal forest zone, which occupies about a third of the area of all forest plantations in the world, makes it difficult to carry out high-quality reforestation work on these areas due to active logging. Due to increased atmospheric moisture and low evaporation, a certain part of the soil profiles of the boreal belt is occupied by wetland or temporarily waterlogged land, where reforestation is carried out using a special technology – planting material is planted in discrete or linear microhills, which can be mounds, platforms, ridges or surfaces created by forest plows. Therefore, the development of modern designs of forest plows for effective work on soils with a watering high degree is an important task for domestic forestry engineering. To determine the optimal design and technological parameters of the designed plow, it is advisable to use methods of mathematical modeling and subsequent optimization. The purpose of the work is to substantiate the basic relations of the formalized model of the process of moving soil along the working surfaces of a semidigger body and a spherical disk of a forest plow during the formation of linear microhill. The stages of the process of moving soil masses, according to the verbal model of the plow, are divided into blocks: cutting the soil surface with a bottom ploughshare, turning the surface with a plowshare and the transition of the soil volume to a spherical disk, followed by the descent of the soil from it for laying in microhill. For each block of the model, a formalized description of the processes is performed using the generally accepted physical and mechanical properties of the treated soil medium. The subsequent implementation of the model in the form of a software package for conducting simulation experiments makes it possible to assess compliance with the standards of the geometric dimensions of the transverse profile of the created microhill with various design and technological parameters of the forest plow, as well as the nominal tractor traction power expended, sufficient for cutting and moving over the surface of the semidigger body of waterlogged land.

For a theoretical study of the process of interaction between the working bodies of a combined tool with forest soil, a mathematical model has been developed. The aim of the study is to develop a mathematical model based on the method (DEM), which makes it possible to evaluate the influence of the parameters of the combined tool, the technological parameters of the process and the parameters of the forest soil on the power characteristics experienced by the tool. With the help of the developed model, the principle of combining working bodies was tested, that is, simultaneous tillage by working bodies of two or more types installed one after another. For this, computer experiments were carried out on the movement of the combined tool in the forest soil until the tool entered the steady-state processing mode. On the basis of a series of computer experiments with the model, the nature of the influence of the parameters of the combined tool, technological parameters of the process and forest soil parameters on the power characteristics experienced by the tool has been established. It was determined that the force of resistance to the movement of the combined tool for wet sticky soils is 0.886 times lower than the sum of the forces of resistance to the movement of individual working bodies. For dry sandy crumbly soils, this effect of 0.985 is practically not expressed. The particle dynamics method was used for modeling. The virtual soil channel had a length of 4 m and a width of 1.2 m. The horizontal speed of the working body was set equal to 1 m/s, and the total model simulation time was 3 s. To cover a wide range of forest soil parameters, experiments were carried out with soils of two types: wet chernozem with significant soil cohesion and dry crumbly sandy soil.

Numerous studies in various timber industry regions of the Russian Federation and climatic conditions have made it possible to formulate a scientific position, which states that when skidding a pack of wood in various soil-soil and climatic conditions, the engine load coefficients in terms of speed (Ks), torque (Kt) and power (KN) are quite stable. The stability of the values of the coefficients KЗ, Kn, KЗ when skidding a pack of wood in a specific gear in various production conditions is taken as the basis for predicting operational, load and design modes and in creating a theory of operational efficiency of skidders. A method for determining the coefficients of joint operation of the engine with a hydromechanical transmission is proposed, the values of which are the basis for predicting the operating conditions and operational efficiency of wheeled skidders. When developing new or improving serial skidders, it is necessary to have an idea of the influence of parameters and technical solutions used in mechanisms, systems and assemblies on the operating modes of the machine, which determine the load of structural elements, and, consequently, its reliability and technical and operational indicators, including those affecting the operational efficiency of work.

The article describes a new simulation model of wood harvesting processes developed by the author and implemented in the AnyLogic software package. The model allows to describe cutting areas of any configuration, vary the characteristics of the forest stand and simulate both clearcut and non-clear cuts, simulate the operation of logging and timber transport machines of various compositions (harvester + forwarder, feller bunchers + skidders, etc.), change the number of involved forwarders and skidders, take into account the restrictions on the safety of work and spatial technological limitations. Animation of the simulating processes greatly facilitates the work with the model.

The article discusses various materials used for the production of power transmission poles. One of the promising materials for the manufacture of power transmission poles is modified wood obtained by uniaxial pressing. In terms of its performance, modified wood is significantly superior to natural wood. Depending on the type of raw materials and technologies, pressed wood can have different densities, which have a significant impact on the operational properties of power transmission poles. The achievement of the necessary strength indicators is achieved at the expense of an unjustified increase in the size of the cross-section of power transmission poles. Climatic factors influencing the service life of modified wood are considered. A constructive solution was adopted to connect the splice elements to a spike with fixing brackets, eliminating possible movements in all directions and preventing the possible rotation of the two constituent elements. As a result of the calculations carried out on the strength of the spliced elements of power transmission poles, it was found that the crosssectional dimensions of a beam made of modified birch and aspen wood, recommended by regulatory documents, are overestimated with the specified strength parameters. The optimal dimensions of the cross-section of the power line column have been determined, taking into account the harsh operating conditions during the cold season and a high degree of icing. The calculations performed make it possible to reduce the consumption of raw materials for the production of pressed wood is for birch and aspen wood. The production of power transmission poles from modified wood is a promising direction for the development of the production of power transmission poles.

The article discusses the effect of pre-sowing treatment of wheat seeds with a solution of wood vinegar on germination, root length and growth intensity. The wood vinegar used in the article is a product of separation of liquid pyrolysis products of wood waste. The pyrolysis liquid was obtained at the industrial fast ablative pyrolysis plant FPP02. The article presents the material balance of the yield of biomass pyrolysis products. The yield of liquid products was 56%. The extraction of wood vinegar took place in laboratory conditions using a rotary evaporator. Analysis of the chemical composition of the isolated wood vinegar by gas chromatography-mass spectrometry (GC-MS) showed a significant content of acetic acid (58.68%), furfural (10.63%), as well as some phenolic compounds (10.69%). To assess the effect of the acetic fraction on sowing, wheat seeds were pretreated with a solution of wood vinegar and water in the following ratios: 1:50, 1:100, 1:200, 1:400. Seeds pretreated in water were studied as a control sample. After treatment, seed germination and root length were evaluated. Then the germinated seeds were planted in the ground to assess the intensity of growth. To do this, measurements were made of the length of the green part of the shoots. The study established both the stimulating and toxic effects of soaking wheat seeds in solutions of wood vinegar. Pretreatment of seeds with wood vinegar led to an increase in seed germination by 10%, an increase in root length by 56%, and an increase in the length of sprouts by 24%. However, the nature of the effect depends on the concentration of wood vinegar in the soaked solution.

Samples of plastic without resins (PWR) based on wood filler in various ratios with hydrolyzed lignin were obtained. The PWR samples were pressed in a sealed mold at a pressure of 40 MPa and a temperature of 180 C, followed by its cooling without pressure relief to 40 C. The obtained samples were tested for bending strength, for water absorption in 24 hours and 30 days, and for biostability with respect to active soil in 21 days. Also, the acquired color characteristics of the front surface were determined in the samples in order to evaluate decorative indicators. Based on the obtained test results for the minimum necessary properties for finishing materials (strength, water and bio-resistance, decorative properties), a rational ratio of the press composition with the content of hydrolytic lignin in the range of 40-60% was established. With this ratio, the following indicators of the material are achieved: bending strength – 11.4–12.4 MPa; water absorption in 24 hours – 27%; water resistance of the material without the onset of destructive processes reaches up to 21 days; biostability in the presence of a constant moist and pathogenic environment is local without through erosion, the color coloration of the front surface by a sixteen– digit color coding corresponds to the colors from jade to spruce.

The stability of dilute (0.1 g/dm³) aqueous dispersions of sulfate lignin (SL) in a wide pH range (2–12) in the presence of 10^–4 M Al₂(SO₄)₃ was studied in the temperature range of 0–20 C. An extreme dependence of stability on temperature with a minimum in the region of 10 C was found. At all temperatures, the maximum deposition of SL is observed in the pH range of 4-6. It is suggested that in the studied temperature range, the observed effect is due to a change in the structure of the boundary layers of water surrounding the SL molecules and the morphology of the formed SL aggregates, which affect the rate of their sedimentation.

New compositions for the treatment of natural wood based on by-products of the production of polybutadiene and methyl methacrylate have been developed. Used for the preparation of the impregnating composition by-products of the production of polybutadiene had the following composition, wt %: 4-vinylcyclohexene – 36.4; toluene – 45.6; heavy residue (butadiene trimers and other products) – 18. Methyl methacrylate was obtained by destruction of polymethyl methacrylate, carried out at a temperature of 220 C. Pinane hydroperoxide was used as a radical initiator. The resulting oligomeric product in all cases had an increased content of methyl methacrylate units. The dosage of methyl methacrylate also affects the molecular weight of the obtained oligomers, which increased with an increase in the content of methyl methacrylate in the initial monomer mixture. The prepared oligomeric solutions after the introduction of the desiccant (4-6% per oligomer) were used for the manufacture of wood-polymer composites. The introduction of the resulting oligomers into samples of natural wood was carried out by immersing them in a toluene solution and kept at a given temperature (20, 60 and 100 C) for 10 hours. The impregnated wood samples were placed in a chamber for high-temperature treatment at a temperature of 160 ± 2 0С for 5 hours. The oligomer content in the prepared woodpolymer composite varied from 10 to 20% and depended on the temperature of the impregnating composition. The wood-polymer composites obtained with the content of methyl methacrylate in the initial monomer mixture of 30% wt and impregnating composition temperature of 100 C have the best performance. It is shown that the treatment of birch wood with an oligomer from by-products of polybutadiene production makes it possible to improve such properties of wood as water absorption, swelling in the tangential and radial directions.

Wood biomass is a source of energy and raw materials for the industrial production of biomaterials, biochemicals, biofuels and other processed products. In addition to the main chemical components (cellulose, hemicellulose, lignin), wood contains a wide range of low-molecular compounds, such as extractives. The content of extractive substances in wood coming to pulp cooking can vary widely depending on the type of wood, age of trees, harvesting season, time and place of storage, and many other factors. The influence of various factors has been well studied, but some nuances remain unclear. In this paper, the influence of the storage time of freshly cut deciduous wood in the open air on the resin content in wood and unbleached sulfate cellulose was investigated. At the same time, special conditions for storing wood were observed in order to minimize the influence of other factors on the resin content in the wood. Also in this study, data on the resin content in the wood coming for cooking for 2 years of observations are given. This made it possible to identify additional patterns associated with the peculiarities of local production, territorial and weather conditions, which may have a decisive influence on the resin content in the wood coming for cooking. When storing wood in production conditions, the lowest resin content in the wood coming for cooking is observed in the autumn period, the highest in winter. An increase in the storage time of wood leads to a decrease in the resin content in unbleached sulfate deciduous cellulose, at the same time, the breaking length of the cellulose decreases slightly.

The content of heavy metals: mercury, cadmium, iron, lead and arsenic was determined: in various parts of xylotrophic mushrooms fruit bodies: Pholiota squarrosa, Kuehneromyces mutabilis, Flammulina velutipes, Pleurotus pulmonarius. The content of heavy metals was determined by absorption spectroscopy before and after extraction with water an atomic absorption spectrometer with electrothermal atomization. Most of the studied mushrooms do not meet the requirements of sanitary rules for the content of arsenic and cadmium. The lead content was found to be high only in the P. pulmonarius and caps of K. mutabilis. Also, K. mutabilis is high in mercury. Iron and lead predominate in all studied mushrooms, arsenic is higher in K. mutabilis and F. velutipes, and cadmium is higher in P. squarrosa. The fruit bodies of K. mutabilis contain more heavy metals. The fruit bodies of F. velutipes contain less heavy metals except for cadmium. Elements, apparently, come from the wood substrate, accumulate in the mycelium and then enter the fruiting bodies. In most cases, there are more heavy metals in the caps than in the stems, which is explained by the similarity of the transport of contaminants with the transport of the necessary elements into the caps. The ability of elements to be extracted by water from the fruiting bodies of mushrooms depends on the element and on the fruiting body part. Mercury is poorly extracted with hot water from the fruiting bodies of mushrooms. Lead is not extracted by water from F. velutipes, but is well extracted from other mushrooms. Cadmium is not extracted from the caps of K. mutabilis and the stems of P. squarrosa; iron and arsenic are generally well extracted.