Variability of Siberian stone pine cones yield in conditions of introduction to the taiga zone of the East European Plain

The change in the carbon stock in the soil cover during the uplift of fallow areas on leached black soils is considered. The aim of the study is to compare dynamics of carbon stock on fallow lands of black soils. Two objects of the study are in the central part of the Russian Federation in Penza region, which belongs to forest and forest-steppe climatic zones. Studies were carried out on two sites typical for the study area, differing in mesorelief and water regime. Object one is a fallow land of floodplain 30-year-old deposits with meadow vegetation characteristic of the region on meadow-black soil and leached black soil humus heavy loamy hydromorphic soils. The second fallow land is located on the territory of 30-year-old deposits overgrown under birch tree plantation with leached medium-humus heavy loamy black soils. Four control sites were laid on each field, differing in the period of cultivation. The carbon stock in the soil in the thickness of the arable horizon was estimated in the course of the conducted studies. Greenhouse gas emissions were estimated using chambers that do not violate soil flows with further analysis of the selected gases on a chromatograph. The research results demonstrate the spatiotemporal dynamics of carbon dioxide emissions, the maximum values were tracked on a 30-year-old forest fallow site, and the minimum values on a meadow fallow ecosystem. The dependence of soil flows is associated with the warming of the soil cover, the density of soil horizons and the fallowness of the territory, since the amount of available carbon dioxide is elevating due to a large increase in vegetation biomass and litter. Carbon stocks in the arable horizon varied depending on the location of key sites in the relief, soil type, seasonality and mechanized intervention of agricultural machinery. Siberian stone pine is a valuable introduced species in the taiga zone of the East European Plain. In general, this type of pine is cultivated to produce pine nuts. Seed productivity is an important feature of breeding for Siberian stone pine. It also serves as an indicator of adaptive potential for introduced species. The research was conducted to assess the variability of the Siberian stone pine cones yield under conditions of introduction to the taiga zone of the East European Plain. Observations of seed-bearing Siberian stone pine were carried out in one of the oldest plantations of this tree species in the taiga zone of the East European Plain: Chagrino cedar grove, located in the Gryazovets municipal district of the Vologda region. In 2013-2024, the number of cones in the crowns of selected model trees was calculated in this cedar plantation, which made it possible to identify their individual variability on this basis, as well as the plantations overall reproductive capacity. The research results allow us to conclude that the seed production rate of Siberian stone pine in the new soil and climatic conditions corresponds to its biological characteristics, since no years with a complete lack of harvest were detected during the study period. On average, the yield of one tree is 131 ± 17 cones. In addition, correlative features have been identified that allow for the selection of high-yielding individuals. Research data indicate that relatively short individuals with a narrow but extended crown should be selected as maternal producers for further breeding.