Productivity and Carbon Sequestration of Pinus sylvestris L. Ribbon Forests in the Dry Steppe of Western Siberia According to Dendrochronology and MODIS Satellite Measurements

Changes in the productivity of Pinus sylvestris L. have been analyzed by remote sensing (gross and net primary production/photosynthesis) and dendrochronology (tree radial growth) methods on two forest plots of ribbon pine forests of different ages in the dry steppe of Western Siberia. For both plots (young reforestation plantings and natural forest), a significant positive trend of change in primary production volume over the period 2000–2023 is revealed. Differences in the set of climatic factors limiting stand primary production volume (spring and fall temperature and precipitation) and radial growth of pine are determined (last September, temperatures were significant for pine of different ages; the sum of annual precipitation and Selyaninov hydrothermal coefficient of the growing season were also significant for young stock, and the temperature in June was also significant for mature forest). Correlations between the width of annual growth of model trees and primary stand production in June and early July for natural forest and in the second half of June for plantations are established. Calculations of the annual volume of carbon sequestration by trees based on tree-ring and biometric data show that, on average over the last 5 years, pine in the table fraction deposited from 525 g C/year (young stock) to 565 g C/year (mature trees). The results of calculations of carbon sequestration volumes (for single-age pine plantations) are comparable in absolute terms and correlate with the values of primary stand production obtained remotely.