This paper presents the evaluation and digital mapping of forest growing stock volume (GSV) and carbon stocks of the natural park Kandry-Kul (Republic of Bashkortostan, Russia). The field observations were conducted in the process of forest surveys in 1994 and 2018. According to these materials, we identified the predominant tree species in each studied plot. Then, we produced the digital maps of GSV and carbon stocks for each study year and calculated the annual increment. The results showed that birch (Betula pendula) and pine (Pinus sylvestris) were the dominant species in the studied park. The comparison of the two maps showed that the maximum annual GSV between 1994 and 2018 occurred in areas with a fairly small GSV in 1994. These areas were characterized by young trees of different species and pines of different ages, which had not yet reached the age of maturity, when the growth of trees is significantly reduced. We found that young pine crops contributed the greatest potential of carbon sequestration, with an annual GSV of 4.2 m³/ha per year. The birch trees made a minor contribution to the sequestration potential, characterized by relatively average annual growth (1.2 m³/ha per year). The change in carbon stocks for pine stands was on average 2 t/ha per year. For birch stands, the change in carbon stocks was approximately 0.5 t/ha per year, which is 30% of the average values for the forest-steppe region. Our results provide quantitative information on the carbon accumulation rate in secondary forests under conditions of intensive recreational load.

The process of climate warming significantly affects agroclimatic resources and agricultural production. We study the agroclimatic resources and their variability on the territory of the Republic of Bashkortostan (Russia). The Bashkortostan has a high agricultural potential and holds a leading position in the country in the production of grain crops, potatoes, milk, and honey. Currently, no detailed studies have been conducted for this area to assess the effects of global climate change on agro-climatic resources. World experience shows such research becomes strategically important for regions with powerful agricultural production. We used the sums of average daily air temperatures above 0 and 10 °C, the G.T. Selyaninov hydrothermal coefficient, and the Ped aridity (humidification) index as agroclimatic indicators. We used data of long-term meteorological observations of 30 meteorological stations for the period of 1961–2020. We revealed the long-term dynamics of the agroclimatic indicators and the spatial and temporal regularities in their distribution on the territory of Bashkortostan. There is a steady increase in the sums of average daily air temperatures above 0 and 10 °C. Against this background, aridity increases, which is especially manifested in the southern parts of the Republic of Bashkortostan. We assessed the impact of agroclimatic indicators on the main types of agricultural crops in the republic. We revealed that the greatest positive impact on the yield of oilseeds, cereals, and industrial crops is made by precipitation at the beginning (r = 0.50, r = 0.44, and r = 0.52, respectively) and in the middle of the growing season (r = 0.55, r = 0.76, and r = 0.51, respectively). Temperature and precipitation during the growing season have a complex effect on cereals. This is proven by correlations with HCS and the Ped index (r = 0.45 and r = −0.56, respectively). Aridity at the beginning of the growing season affects the yield of oilseeds and potatoes. This is confirmed by correlations with the Ped index (r = −0.49 and r = −0.52, respectively). In general, the aridity of the growing season has a significant impact on the yield of cereals (r = −0.57). Negative relationships have been found between the air temperature growing season and the yield of potatoes (r = −0.50) and cereals (r = −0.53). The results of the study were compared with data from the Copernicus Climate Change Service database. We identified climate trends under RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5 scenarios. These scenarios should be taken into account when developing plans for the adaptation of agriculture in the Republic of Bashkortostan to changes in the regional climate. Maximum decrease in precipitation is established for the RCP 6.0 scenario. This can have an extremely negative impact on crop yields. This problem is especially relevant for the southern part of the Republic of Bashkortostan. The information presented in the study will allow for a more effective adaptation of the agricultural sector to current and future climate changes.

This study investigated carbon sequestration potential in reforesting agricultural lands with prevalence of Scots pine (Pinus sylvestris L.) in the “Nasibash” site of the Eurasian Carbon Polygon, located in the Republic of Bashkortostan, Russia. The research focused on analyzing carbon stocks in different ecosystem components (tree stand, herbaceous layer, litter, and soil) across various stages of succession, including fallow land, hayfield, and four stages of Scots pine reforestation. We found that needles during the first stage of succession were characterized by the highest carbon sequestration, while the lowest was in underground phytomass (roots). The tree stand exhibited a higher potential for carbon sequestration in stem wood, branches, and needles compared to other components. The highest carbon accumulation in the tree layer was observed in the stem phytomass at the fourth stage of reforestation, while the highest phytomass accumulation in the herbaceous layer was in the root mass at the fourth stage of succession. The study revealed that the highest organic carbon content in the topsoil layer was observed in areas dominated by herbaceous vegetation, with a decrease in carbon content as the stage of succession increased. The highest carbon content was found in tree pines at the first stage of succession. The research highlighted the importance of considering conversion factors for different stages of reforestation, as the average carbon content in vegetation was 20% higher than the approved conversion factors for young tree stands. Overall, the study demonstrates the significant potential of Scots pine reforestation on former agricultural lands for carbon. The findings suggest that these territories play a decisive role in future environmental and climate projects, contributing to the decarbonization efforts.

There is growing recognition that forest ecosystems are a key component in the global carbon cycle, and there is a clear demand for their study. This research is a comparative analysis of forest growing stock volume (GSV) and determination of annual growth in Bashkiriya Nature Reserve (Russia) for 1979 and 2015 using 8395 and 8405 observation plots, respectively. Also, we evaluated the spatial distribution and produced digital maps of the species and their GSV for each year. The results showed that pine and birch were the dominant species (60.5 and 24.8% of the area in 2015, respectively) and there were no significant changes in the area of stands during the 36-year period. We found that the GSV in the reserve had increased by an average of 23.2% over the 36-year period. Specifically, the total forest GSV increased from 7,678,960 in 1979 to 10,003,890 m³ in 2015, representing an annual gain of 0–1.5 m³/ha. The increase in GSV was mainly associated with an increase in birch and pine trees. The annual growth of GSV was determined as 1.8–2.1 and 1.4 m³/ha per year for pine and birch forests, respectively. However, these types of trees belong to the age categories of mature and overmature stands, i.e., with reduced intensity of GSV gain. Digital maps produced as part of this study provide a visual representation of the changes in forest spatial patterns and GSV over time, highlighting areas of the reserve where the stock has increased or decreased. This study leveraged a substantial dataset, which provided valuable retrospective insights into the dynamics of pristine forest ecosystems, allowing for the assessment of changes over a 36-year period. Overall, this study highlights the importance of the ongoing monitoring and assessment of GSV levels, especially in the context of rapidly changing environments and climates.

Цель – определение наиболее зависимых от изменения температурного режима типов растительности на участке «Геопарк Янган-Тау» (площадка «Насибаш») Евразийского карбонового полигона (Республика Башкортостан). Материалы и методы. Проведен анализ динамики показателя NDVI с мая по сентябрь с 1982 по 2022 годы с использованием 110 изображений Landsat, с объединением в группы по 5 лет. Определены среднее значение, мода и медиана показателя NDVI для каждой пятилетки. Для дистанционной оценки температурного режима использовались снимки программы Landsat 8-9. В программе SAGA GIS оценена связь температуры поверхности Земли и NDVI для каждого бесснежного месяца с использованием усредненных изображений температуры поверхности Земли и NDVI. Построены карты пространственного распределения коэффициента детерминации (r2). Результаты и обсуждение. Для июня месяца характерно увеличение значения NDVI. Май, июль и август месяц не демонстрируют значительных изменений, а среднее значение и медиана для сентября имеет тенденцию к снижению. Наибольшую связь между NDVI и температурой поверхности Земли показывают зарастающие сосной залежные земли (4 стадия зарастания), не заросшие залежные земли и сенокос. Выводы. Вегетационная активность растительности на участке карбонового полигона «Геопарк Янган-Тау» увеличилась с 1982 для июня месяца, что обусловлено влиянием температуры мая. Наибольшую устойчивость к изменениям температурного режима продемонстрировали участки, находящиеся в 1 и 3 стадии зарастания сосной.

The study was conducted on the territory of the "Nasibash" site of the Eurasian carbon polygon, where 9 vegetation communities were identified. The approach to estimation and construction of soil temperature distribution maps using Landsat 8-9 space images is presented. Evaluation of vegetation response to soil temperatures was carried out using vegetation indices: NDVI, GNDVI, EVI, CVI. The use of statistics of the obtained rasters made it possible to reveal the dependence of the values of vegetation indices on soil temperature. GNDVI demonstrated the greatest relationship: r = 0.82, R² = 0.65. Further, the effect of soil temperature on individual plant communities was evaluated. Plots with 4 (r=0.74, R² = 0.55) and 3 stages (r=0.47, R² = 0.23) of pine (Pinus sylvesrtis L.) overgrowth and hayfield (r=, 0.54, R² = 0.29) showed the highest correlations.